Eunavi VW PX5 H/W identification + Sound Mod Advice + improvements - MTCD Hardware Development

I have a eunavi PX5 4G/32G with an inbuilt VW Quadlock. The unit has following sound related issues (when in a Skoda Superb 2011);
- when no media is being played, significant background noise can be heard (white noise + clicks, etc). in particular, when downloading over wifi, the noise varies as the load on the CPU varies.
- visible engine noise in the rearview camera
- high level of background noise can be heard when media played from the USB, microsd and less noticeable with the radio.
when on the desk power supply,
- the is persistent low level white noise, but without the clicks, etc and no downloading induced noise.
- the low level white noise is persistent across radio, media, etc.
decided to bite the bullet, and open the unit up, hoping to install the DSP mod.
- Notably the amp chip is located next the power supply,
- the audio chip is on the rear side of the board from the powersupply / amp
- the clock does not have shielding around it, allow the board clearly was designed with that intention
can anyone identify the actual manufacturer of this board and help with the DSP mod
https://www.alibaba.com/product-det...ml?spm=a2700.icbuShop.41413.34.77eb1e36Nr5kPU
https://www.aliexpress.com/item/4000274050022.html?spm=2114.12010612.8148356.24.6030147dlf1vAh
I have updated the
- MCU to MTCE_HA_v3.40_1
- system to px5-userdebug 8.0.0.0 OPR5.170623.007 eng.hct.20190428.180147 test-keys
update went smoothly.
It would seem that the sound problems are a grounding and/or VW noise issue powered via the quadlock connector
(i note it is not possible to power via the quadlock connector on the bench - presumably because no canbus connected)
The big question is, can i install a DSP and will it reduce the white noise problem.

I have the same media player with DSP, and have the same problems with background noise. Contacted the seller, and he sent me a new main board - the problem still exist, after replacing the board. The player is mounted in Honda Accord. Tried changing the capacitors - same **** different day ...
Will be following the tread if any solution comes up.

As7i said:
I have the same media player with DSP, and have the same problems with background noise. Contacted the seller, and he sent me a new main board - the problem still exist, after replacing the board. The player is mounted in Honda Accord. Tried changing the capacitors - same **** different day ...
Will be following the tread if any solution comes up.
Click to expand...
Click to collapse
can you make a photo of the board and particularly identify where the DSP is.
thks

gwaitsi said:
can you make a photo of the board and particularly identify where the DSP is.
thks
Click to expand...
Click to collapse
No idea where the DSP is ... For me it is just a board with some elements and chips on it, no idea what is what. But there are the pictures of the board, if they could be in any help for you.
<<<https://imgur.com/a/l7XVbuz>>>
Copy and paste the link only without "<<<>>>" ... had to cheat the forum since new users are not allowed to attach or send links...

As7i said:
No idea where the DSP is ... For me it is just a board with some elements and chips on it, no idea what is what. But there are the pictures of the board, if they could be in any help for you.
<<<https://imgur.com/a/l7XVbuz>>>
Copy and paste the link only without "<<<>>>" ... had to cheat the forum since new users are not allowed to attach or send links...
Click to expand...
Click to collapse
It's not the same board. It is almost the same, but obviously a different revision. Turn the rear view so your thumb is on top. bottom left corner. You are missing the audio ZL3560 chip and the one below it. slightly to the right of the ZL3560 you have a square chip but i cant see the number on it with the quality of your pic.
Do you here varying background noise when downloads are occurring over wifi.
i uploaded your pics for the benefit of others

gwaitsi said:
It's not the same board. It is almost the same, but obviously a different revision. Turn the rear view so your thumb is on top. bottom left corner. You are missing the audio ZL3560 chip and the one below it. slightly to the right of the ZL3560 you have a square chip but i cant see the number on it with the quality of your pic.
Do you here varying background noise when downloads are occurring over wifi.
i uploaded your pics for the benefit of others
Click to expand...
Click to collapse
I have not used the WiFi yet. I had a varying background noise while I was browsing the menu, and every touch of the screen was reflected in the speakers. I gave the media to a repair shop and they changed all the capacitors. Now the noise from browsing the menu is gone, but still there is hell of a "turbo" noise. I can clearly hear my rpm in the speakers. And the problem is gone with other players. Tested the same player to a different car - same "turbo" noise. Tried a "hi-low" filter/converter - the idea was not to use the RCA out ... and the problem became even bigger.
Now the car is in a car audio service, the boys will try to fix the noise, or the medial will be replaced. If it comes to replacing the media unit, since the EUNAVI shop won't assist anymore, claiming that there is no way their media to have such a problem ... the defective unit will gladly be run over by my car ... several times - just to be sure it is dead ...

I've tried 3 different boards with and without DSP and the solution was to turn down the gain on the amplifier. I'm using RCA.
However, I noticed a significant improvement when I plugged the microphone into the back of the unit. Can you test this out and let me know? Both microphones broke on this unit, I'm not sure why, but the whining is gone until I turn the gain on my amp up. It sounds pretty good now, especially after tuning with the dsp board. I'll still be returning it though to try a Dasiata board.
Regarding USB audio: my eunavi board has terrible white noise pops clicks. My newest unit(CHS) has no issues over USB audio. It's flawless. Im thinking about using a HDMI to RCA converter for digital audio and hooking it up to a helix for auto digital /analog switching.
Sent from my LYA-L0C using Tapatalk

As7i said:
I have not used the WiFi yet. I had a varying background noise while I was browsing the menu, and every touch of the screen was reflected in the speakers. I gave the media to a repair shop and they changed all the capacitors. Now the noise from browsing the menu is gone, but still there is hell of a "turbo" noise. I can clearly hear my rpm in the speakers. And the problem is gone with other players. Tested the same player to a different car - same "turbo" noise. Tried a "hi-low" filter/converter - the idea was not to use the RCA out ... and the problem became even bigger.
Now the car is in a car audio service, the boys will try to fix the noise, or the medial will be replaced. If it comes to replacing the media unit, since the EUNAVI shop won't assist anymore, claiming that there is no way their media to have such a problem ... the defective unit will gladly be run over by my car ... several times - just to be sure it is dead ...
Click to expand...
Click to collapse
Interesting. From the menu, i also get basic touch screen noise. Downloading just makes it more prominent. I am use the ISO connector for Skoda.
I would say you probably have a ground problem if you are engine noise. You want to make sure, if using an ext amp, the two units are grounded together at the same point.
I will take a look at the caps as well.

lennylen said:
I've tried 3 different boards with and without DSP and the solution was to turn down the gain on the amplifier. I'm using RCA.
However, I noticed a significant improvement when I plugged the microphone into the back of the unit. Can you test this out and let me know? Both microphones broke on this unit, I'm not sure why, but the whining is gone until I turn the gain on my amp up. It sounds pretty good now, especially after tuning with the dsp board. I'll still be returning it though to try a Dasiata board.
Regarding USB audio: my eunavi board has terrible white noise pops clicks. My newest unit(CHS) has no issues over USB audio. It's flawless. Im thinking about using a HDMI to RCA converter for digital audio and hooking it up to a helix for auto digital /analog switching.
Sent from my LYA-L0C using Tapatalk
Click to expand...
Click to collapse
I have a factory fitted blaupunkt amp and connection via the ISO connector. The gain is currently set to -12dB and the amp mode is set to auto detect.
I might take the oscilloscope out when it warms up and have a look,.

As7i said:
I have not used the WiFi yet. I had a varying background noise while I was browsing the menu, and every touch of the screen was reflected in the speakers. I gave the media to a repair shop and they changed all the capacitors. Now the noise from browsing the menu is gone, but still there is hell of a "turbo" noise. I can clearly hear my rpm in the speakers. And the problem is gone with other players. Tested the same player to a different car - same "turbo" noise. Tried a "hi-low" filter/converter - the idea was not to use the RCA out ... and the problem became even bigger.
Now the car is in a car audio service, the boys will try to fix the noise, or the medial will be replaced. If it comes to replacing the media unit, since the EUNAVI shop won't assist anymore, claiming that there is no way their media to have such a problem ... the defective unit will gladly be run over by my car ... several times - just to be sure it is dead ...
Click to expand...
Click to collapse
lennylen said:
I've tried 3 different boards with and without DSP and the solution was to turn down the gain on the amplifier. I'm using RCA.
However, I noticed a significant improvement when I plugged the microphone into the back of the unit. Can you test this out and let me know? Both microphones broke on this unit, I'm not sure why, but the whining is gone until I turn the gain on my amp up. It sounds pretty good now, especially after tuning with the dsp board. I'll still be returning it though to try a Dasiata board.
Regarding USB audio: my eunavi board has terrible white noise pops clicks. My newest unit(CHS) has no issues over USB audio. It's flawless. Im thinking about using a HDMI to RCA converter for digital audio and hooking it up to a helix for auto digital /analog switching.
Sent from my LYA-L0C using Tapatalk
Click to expand...
Click to collapse
gwaitsi said:
I have a factory fitted blaupunkt amp and connection via the ISO connector. The gain is currently set to -12dB and the amp mode is set to auto detect.
I might take the oscilloscope out when it warms up and have a look,.
Click to expand...
Click to collapse
I've been following noise issue on PX5 for a while (they all have them) but no one on this forum found the right fix (better ground, change caps, install DSP,ground heatsink of PX5, solder RCA directly nothing really fix it)
Did you solve the problem?

ELCouz said:
I've been following noise issue on PX5 for a while (they all have them) but no one on this forum found the right fix (better ground, change caps, install DSP,ground heatsink of PX5, solder RCA directly nothing really fix it)
Did you solve the problem?
i didn't yet, but can say many of the problems are not there when the unit is on the test bench using PSU rather than in the car. I have a filter and will put that in the car when i have chance. There is definitely a difference in the unit power design. If i try to power via the quadlock connector on the work bench, it doesn't power up. i have to use the non-quad connector. so would be interesting to know if the same unit is working better in a car without the quadlock connector
Click to expand...
Click to collapse

Could it be that the hardware is fundamentally flawed.

marchnz said:
Could it be that the hardware is fundamentally flawed.
Click to expand...
Click to collapse
it's most likely a combination of cheap components e.g. capacitors, grounding issues and RF isolation/shielding and cheap design shortcuts. it is clear, if you disassemble the unit and move the screen away from the CPU & baseboard, there is less interference from the touch screen. Also supporting that, my unit has an onboard VW Quadlock so it direct plug/play. There is clearly engine noise which doesn't appear with the original blaupunkt unit. But you pay one tenth of the price...so what can you expect. the question is, if you can do enough e.g. add noise filters in line for the quadlock to reduce the problems to an acceptable level.
The bigger issue in my mind is the inbuilt malware. My unit tries to contact a tencent IP address, and also probes the ports on my firewall if i connect the wifi to my guest network ;-)

So finally, I bit the bullet and started to work on solving the issues.
First step is to reduce the engine noise on my 2011 Superb 3T5 Diesel,
which is also particularly amplifier when using USB DAB.
Two possible options
1) so-called camera Rectifier is a 1000uF/16v cap on the input side with a IN4001 rectifier diode and a small cap (probably 10uF not sure) on the output.
2) so-called car power Filter is an inductor with a 2200uF/25V cap on the output side of the inductor.
You can see on the 2nd photo there is an inductor and 4700uF capacitor. I didn't trace the circuit yet,
but I guess this is on the power input from the RCA connector strip and not the Quadlock/VW ISO connector.
I hooked up a scope to the Quadlock connector power and there was noise and a sine wave on it. Although the Quadlock diagram for the Superb shows
12 – Voltage supply, negative, terminal 31
15 – Voltage supply, positive, terminal 30
16 – Anti-theft coding control signal, SAFE, positive
I connected one box of 1) on pin 15 and one box of 1) on pin 16.
There is about a 1v drop on the power to the unit i.e. 14.1v to 13.1-2v but the solution solved the engine noise and significantly reduced the noise of the DAB.
There is still some screen noise, but I noise there is provision for RFI shields around the various components (which have not been installed). I will try to replace the PCB caps and add some shielding to see if i can cut the screen noise out.

gwaitsi said:
So finally, I bit the bullet and started to work on solving the issues.
First step is to reduce the engine noise on my 2011 Superb 3T5 Diesel,
which is also particularly amplifier when using USB DAB.
Two possible options
1) so-called camera Rectifier is a 1000uF/16v cap on the input side with a IN4001 rectifier diode and a small cap (probably 10uF not sure) on the output.
2) so-called car power Filter is an inductor with a 2200uF/25V cap on the output side of the inductor.
You can see on the 2nd photo there is an inductor and 4700uF capacitor. I didn't trace the circuit yet,
but I guess this is on the power input from the RCA connector strip and not the Quadlock/VW ISO connector.
I hooked up a scope to the Quadlock connector power and there was noise and a sine wave on it. Although the Quadlock diagram for the Superb shows
12 – Voltage supply, negative, terminal 31
15 – Voltage supply, positive, terminal 30
16 – Anti-theft coding control signal, SAFE, positive
I connected one box of 1) on pin 15 and one box of 1) on pin 16.
There is about a 1v drop on the power to the unit i.e. 14.1v to 13.1-2v but the solution solved the engine noise and significantly reduced the noise of the DAB.
There is still some screen noise, but I noise there is provision for RFI shields around the various components (which have not been installed). I will try to replace the PCB caps and add some shielding to see if i can cut the screen noise out.
Click to expand...
Click to collapse
What are the frequency(s)/period of the noise?
The inductor, what is the physical size?
Have you considered using a shottkey diode instead of the 1n4001?

marchnz said:
What are the frequency(s)/period of the noise? i didn't record it, i saw enough to convince i needed a filter.
The inductor, what is the physical size? I never used option 2. because option 1 worked.
Have you considered using a shottkey diode instead of the 1n4001? i wouldn't over analyse. In summary, this could have been fixed by adding capacitors to the motherboard for the CAN connector power rails. Obviously they tried to save a few cents on manufacturing costs, or was simply an oversight in the initial design
Click to expand...
Click to collapse

OK, so youre unsure not sure how to design filters, select the correct components, including filtering and reducing voltage drops.
Not over analyzing, just knowing what the right path is to reducing switching noise.

marchnz said:
OK, so youre unsure not sure how to design filters, select the correct components, including filtering and reducing voltage drops.
Not over analyzing, just knowing what the right path is to reducing switching noise.
Click to expand...
Click to collapse
I provided two links;
1) Half Wave Rectifier
2) Low Pass Filter
of course, you can do this with the raw components for a few cents.
But the two aliexpress links provide them in plastic packaging, which makes them convenient for installing in the car. The half-wave rectifier is a smaller package, so I installed that first. It solved the problem in a much smaller form (given I put in two - without having checked the onboard Quadlock connectors). On the design of my motherboard, it is evident there are no capacitors in the power rails connected to the Quadlock connector (which is the 68pin dual-in-line connector)
While the low pass filter will have less voltage reduction, in this case it makes no difference to the head unit as it is simply reducing the noisy 14v to a clean 13v which is still with range, so frankly, I consider that part of the problem solved.

Related

Car USB Charging Whining Noise

Hi All,
Per the discussion of this thread: http://forum.xda-developers.com/showthread.php?t=1367120&highlight=usb+amazon+charger&page=3
I bought this Car USB Outlet Charger: http://www.amazon.com/gp/product/B002F0200Q/ref=oh_o02_s00_i00_details
It charges under AC mode, but if I also connect the 3.5mm jack to my cars speakers there is a high pitched noise that increases as the RPM of my engine increases (for example if I put my car in neutral the sound is at the lowest frequency, and if i step on it the sound shoots up).
If I remove the charger from the phone the noise stops. If I begin playing music the noise also goes away. If I stop any playing music then the high pitch noise will return after a brief (~5sec) period.
It's not a terrible issue because it doesn't interfere with playing audio, but it is an issue if nothing is playing and the car speaker is turned on.
Would appreciate any insight.
Thanks,
DL
I have the same issue. It's not the phone, it's your car. You are hearing the alternator noise through the electrical. I have some friends who are car audio installers and what you have is a most likely a bad ground on the auxiliary port. I've tried with 3 or 4 phones with my car and they all do it while charging.
From what I understand there's 2 ways to fix it. Have an audio Installer open it up and ground it properly. This takes time and could be complicated depending where the fault is.
There's also a magnetic shielding thing tthat you can pass your auxiliary cable through which is supposed to be like $5. I've not tried the simple fix yet. I keep forgetting to ask what iit is exactly.
Sent from my ADR6425LVW using Tapatalk
Well I was thinking it was an issue with the actual charger, not my car...
I've used a blackberry, and itouch before while charging and going to the car audio without the problem (but this was not with the Belkin adapter I linked to).
Just to be clear when you say an issue with grounding of the auxillary port you are referring to the the 3.5mm input, not the cigarette lighter port?
Let me try switching the cigarette port.
Yeah, the 3.5mm port. I've also tried changing chargers and nothing has made a difference.
so what you are saying is the issue is with my 3.5mm jack even though the noise doesnt come through if the charger is disconnected?
I've never had any problems with other devices when charging and playing audio.
Only with this particular usb charger and my rezound.
happens to me sometimes too...I just act like I'm in some kind of spaceship as I zoom down the highway
I'm thinking to buy something like this to power my devices, probably a good investment...
goo DOT gl/s0wO7 (can't post links yet, redirect to amazon for a powerline 200W power inverter)
Had the problem with a Verizon charger, took it back and the new one worked fine.
You could try some snap chokes (ferrite cores) they snap around the outside of the cables you may have seen them on some of your usb cables, they reduce interference
radio shack search "snap choke" they have two sizes that fit around the outside of the cable, 5mm and 3.5mm ... they come two to a package, try using them on the power wire and if that doesn't work try it on your aux output wire, they just snap on. you can snap them off if you want to remove them, you can use more than one on a cable if that helps
This is not a fix all and may or may not work but this is what they are designed for, it at least may cut down the noise some but no guarantee's
Once you search on radio shack, read the reviews on them you will see what some people are using them for, they are about $3.00 for 2 chokes
craigsdocks said:
You could try some snap chokes (ferrite cores) they snap around the outside of the cables you may have seen them on some of your usb cables, they reduce interference
radio shack search "snap choke" they have two sizes that fit around the outside of the cable, 5mm and 3.5mm ... they come two to a package, try using them on the power wire and if that doesn't work try it on your aux output wire, they just snap on. you can snap them off if you want to remove them, you can use more than one on a cable if that helps
This is not a fix all and may or may not work but this is what they are designed for, it at least may cut down the noise some but no guarantee's
Once you search on radio shack, read the reviews on them you will see what some people are using them for, they are about $3.00 for 2 chokes
Click to expand...
Click to collapse
Thank you for the suggestion. I will certainly take this idea into consideration.
I do think the piece is defective, but the amazon seller only offers a return, and it was only 5$, not sure if its worth the hassle.
The charging circuit on your alternator has a bad filter. The whine you're hearing is the AC generated...the frequency corresponds with your RPM. Basically, the rectifier diodes are doing what they are supposed to and putting that AC into the electrical system as pulsed DC, but there are capacitors and chokes that are supposed to smooth the current out so it doesn't stress out your equipment. It's possible the charger you got doesn't have a filter either. Ensuring your equipment has a good ground should help, but it may not fix the sound...you'd have to replace your alternator.
Its ground feedback. Could be anywhere in your car. Could also be the charger but probably not.
I have a similar effect, but fortunately it does go away once I start playing music. I only hear the noise when nothing is playing. I don't engine noise, just static. I know its related to the changing connect since it goes away when I unplug it.
I was thinking about seeing if there is something to impede interference that I can put inline with the cable or on it.
My aux audio was an PAC Audio connection that I installed, and the dock/charger I have is kind of cheap-o, so I figure its just the price of being frugal.
yes thanks all for the advice and feedback.
@ssb13 yes the sound interestingly stops right before any music plays, and then has a short delay before coming back after the music finishes.
I suspect a ground loop isolator would solve your problems.
Here's one from Kensington on Amazon:
http://tinyurl.com/6m58v6s
But there are several other makes that probably would work equally well. Just do a search on Amazon for a ground loop isolator.
Check out the comments on the Kensington one and see if the problems sound familiar.
I have the exact same problem! It happens with both the AC cigarette charger and the usb cable I have connected through my headunit. I have a cheap radioshack stereo cable as the connection between my rezound and the headunit, but when I've used headphones I don't seem to notice it either because the music is too loud to notice it or there isn't any interference. So I'm assuming the interference is caused by a feedback loop since power comes in from the charger and then audio goes out through the headphone jack and back into the car.
car charger noise
I purchased and installed an EMI/RFI suppressor from Mouser. It is a 2-piece ferrite cylinder that fits around the USB cable coming from the car charger/power supply. Unfortunately, it made absolutely NO DIFFERENCE in the noise. It is the same type of suppressor that is sometimes installed by the manufacturer on power supply output cables, so I was hopeful that it would work. Guess I will try looking for a loose ground connection.
[
A ferrite ("snap choke," "RFI suppressor") won't do a thing at audio frequencies. You're hearing whine from the alternator. It's worse because you have a ground loop - the phone is grounded by both the charger and the audio jacks. It's probably worse when no music is playing because the phone then turns off the output amplifier, making the output a high impedance and letting the noise be heard due to the ground loop. A ground isolator in the audio line will probably help, but may not completely eliminate, the noise. Why not get a Bluetooth audio adapter for your car?
Ground loops suck, at home they can be fixed by breaking off the grounding pin on a power strip and using that. But you can't do that in your car.

High pitch noise when plugged into car's AUX

Full description of the problem:
I just got my EVO 4G LTE the other day, as a replacement to my original EVO 4G. However, I noticed when it was plugged into my car's AUX port, it puts out a high-pitch (like a teapot) noise. This noise happens as long as the headphone jack is powered up (something playing). Even if I turn the phone's volume down all the way, the high pitch is still heard. Otherwise, the audio from the phone can also be heard normally.
Things I've tried:
1. Different cables known to work. All act identically.
2. Headphones. They work fine.
3. Another car's AUX port. Worked fine.
4. Jiggling the jack on either end causes the pitch to change momentarily, but does not go away.
5. Slightly unplugging it from the car side (so one of the channels is not connected) makes it go away, leaving me to believe the high pitch noise is only coming from one channel (I believe the right channel, hard to tell).
Things I don't want to do:
1. Get a new car stereo.
2. Use a Bluetooth adapter. I already have the Stereoclip, and it doesn't do phone calls. Anything else sounds awful with music.
Does anyone have any solutions? I think its some sort of strange feedback/grounding issue, but I have no idea how I would fix this.
I don't have a solution, but I am experiencing the same issue with the phone plugged into my car's AUX. As long as music is playing I can't really hear the whine, but between songs it's pretty annoying.
I haven't tried playing around with the different EQ settings. By default it's been going to Beats. I may switch to a different setting or try a different player like Winamp. I'm currently using the HTC media player.
jasonkc25 said:
I don't have a solution, but I am experiencing the same issue with the phone plugged into my car's AUX. As long as music is playing I can't really hear the whine, but between songs it's pretty annoying.
I haven't tried playing around with the different EQ settings. By default it's been going to Beats. I may switch to a different setting or try a different player like Winamp. I'm currently using the HTC media player.
Click to expand...
Click to collapse
In my experience it has absolutely nothing to do with what app is being used, nor the EQ. It's nothing software as far as I can tell.
This fixes it:
http://www.amazon.com/Kensington-Reducing-SmartPhone-including-iPhone/dp/B0031U1ATQ
if your phone is plugged into the car charger and your audio jack is plugged in to listen to music. what our hearing is a ground loop from the cars alternator. try unplugging the power supply and see if that helps..
papadunit said:
if your phone is plugged into the car charger and your audio jack is plugged in to listen to music. what our hearing is a ground loop from the cars alternator. try unplugging the power supply and see if that helps..
Click to expand...
Click to collapse
The car charger makes no difference. I have tried using nothing but the audio cable in the phone and still had the static.
I was under the impression that a normal ground loop would require a charger, but...
Modplan: are you sure this will fix it if the noise occurs even without the charger plugged in? The noise is high-pitch, not really a hum, so I'm wary as to whether it will help here.
Its not a simple ground loop problem. I wired my power to the phone using a separate ground from the car's common ground and the issue still persisted.
Try cranking the volume up then when you hear the noise, start playing with the touchscreen. When i did this the noise started changing according to the movement of my fingers. I concluded that there is something going on with the grounding of the capacitive display thats causing another grounding issue, but its not an issue with the car, but an issue with the phone.
I didn't want to go through the vicious cycle of returning my phone over and over until i get one that didn't have this fault so i just went with a samsung hs3000 hardwired in to my car.
lacrossev said:
Its not a simple ground loop problem. I wired my power to the phone using a separate ground from the car's common ground and the issue still persisted.
Try cranking the volume up then when you hear the noise, start playing with the touchscreen. When i did this the noise started changing according to the movement of my fingers. I concluded that there is something going on with the grounding of the capacitive display thats causing another grounding issue, but its not an issue with the car, but an issue with the phone.
Click to expand...
Click to collapse
I wasn't able to replicate this.
I've had the same issue, but it's only when charging. I figured it had something to do with the aluminum body and, as papadunit said, a problem with grounding and your car's alternator and blah blah blah science.
modplan said:
This fixes it:
http://www.amazon.com/Kensington-Reducing-SmartPhone-including-iPhone/dp/B0031U1ATQ
Click to expand...
Click to collapse
I'm happy to report that this actually did solve the problem, amazingly. Thanks!
Actually had same issues this passed weekend but with my asus transformer. Was using it for navigation tethering from evo with both charging from my 400w inverter. Plugged transformer into aux and had same high pitching noise only when inverter was plugged in. Even tried different audio cables, same chit.
Sent from my EVO LTE
Headset Jack's other issues
I can confirm the same behavior with my EVO 4g LTE. My HTC Touch Pro 2 or Iphone 4s never had any of these issues with my vehicle's AUX jack. I also verified that if I turn the volume on the phone all the way down that the noise is audible on the vehicle's sound system. It also doesn't matter what player I use or if I add any equalizer settings to the audio. Finally, the noise is present whether the car is running or not.
Can you guys confirm: If you pause the audio on your player does the whine end about 4 seconds after and startup again if you press play? Or if you shut the player down does the noise go away shortly after?
I did some research and some said it has to do with the AUDIO DAC in the phone turning on and off as audio is played, paused, etc. If the output device has high sensitivity these sounds appear.
I had another issue with my Plantronics wired headset distoring when making phone calls. It did not present the whine but it distorted the callers voice as if the treble or bass was too high. I tried various audio settings but nothing changed. With other headsets the issue does not present itself. I think that the audio DAC is also sending higher/lower frequencies that are greater than some headsets can handle.
That Kensington thing that was posted can easily be made with common household parts. Basically all you need to do is take the big bulgy thing from any cable that would have it and attach it to your audio cable. It works best if you have one near each end of the cable. it's called a clamp-on ferrite bead and is just a clip with iron ferrite in the middle. Since i'm new I can't post a link buuuut what I can do is tell you the keywords to look up on google for the ehow link: cable magnets eliminate emi . enjoy!
lacrossev said:
Its not a simple ground loop problem. I wired my power to the phone using a separate ground from the car's common ground and the issue still persisted.
Try cranking the volume up then when you hear the noise, start playing with the touchscreen. When i did this the noise started changing according to the movement of my fingers. I concluded that there is something going on with the grounding of the capacitive display thats causing another grounding issue, but its not an issue with the car, but an issue with the phone.
I didn't want to go through the vicious cycle of returning my phone over and over until i get one that didn't have this fault so i just went with a samsung hs3000 hardwired in to my car.
Click to expand...
Click to collapse
Mine changes pitch according to my cars rpms
Sent from my EVO
I am getting this with headphones, i have used multiple brands and its hit or miss but more hit than miss :laugh:, anyone getting it in there headphone?
I was getting this issue until I installed a custom ROM. Running MeanROM right now with no background noise. Seems counterintuitive to me...but whatever.
J
Sent from my EVO using xda app-developers app
dankorzon said:
That Kensington thing that was posted can easily be made with common household parts. Basically all you need to do is take the big bulgy thing from any cable that would have it and attach it to your audio cable. It works best if you have one near each end of the cable. it's called a clamp-on ferrite bead and is just a clip with iron ferrite in the middle. Since i'm new I can't post a link buuuut what I can do is tell you the keywords to look up on google for the ehow link: cable magnets eliminate emi . enjoy!
Click to expand...
Click to collapse
http://www.radioshack.com/product/index.jsp?productId=3012599
Dankorzon, is this what you're talking about? If so I'm going to go get some tomorrow. I'm having this feedback issue too, but it is only when the car charger is plugged in. But I'd love to get rid of that sound. Drives me crazy.
SOLVED: I used a ground loop isolator
I posted earlier that I had the whining noise in my car even with the engine off. So it wasn't related to an alternator issue. I use a Blitzsafe (blitzsafe.com) device to add a line level input jack to my Honda Accord's stock radio interface. It works well with all my other devices except the Evo 4g LTE. This past weekend I did a little tinkering and noticed that if I pulled the RCA jack on one channel (left or right) every so slightly so the ground tabs weren't touching the noise disappeared. With only one channel connected the noise is not present. I'm not sure why the noise is present with both channels connected but it definitely pointed to a ground loop problem. I did some research in audio forums and some said that a wire could be jumpered so the RCA ground touches the receiver chassis and that would solve the problem. Unfortunately that did not do anything. I touched several different grounding points near the receiver but the sound was always present.
I went to Best Buy and purchased this: http://www.bestbuy.com/site/Fierce+...36.p?id=1218186610567&skuId=9855136&st=ground loop&cp=1&lp=1 It works great. For whatever reason the EVO 4g LTE's DAC must be sensitive or not have the right filter to block the ground signal. This explains why the Kensington product also works.
I also solved my headset issue. I can confirm that older corded Plantronic headsets will not work well with the EVO. The EVO distorts the speaker in the headset. I'm pretty sure it's because it sends lower bass frequencies than the speaker can handle. Only solution was to use a newer headset.
Thanks all for your help.
phiphiJR said:
http://www.radioshack.com/product/index.jsp?productId=3012599
Dankorzon, is this what you're talking about? If so I'm going to go get some tomorrow. I'm having this feedback issue too, but it is only when the car charger is plugged in. But I'd love to get rid of that sound. Drives me crazy.
Click to expand...
Click to collapse
That is what he is talking about, but that is NOT what the kennsington device is. Google "ground loop isolator" for info on what the kennsington is, it is NOT simply an aux cord with ferrite beads on it.
I've got the same problem in my car. This only happens when plugged into the charger. I'm going to try a ground loop isolation device which will arrive sometime next week.
I guess I don't understand why the phone would only do this when no music is playing though. It makes me think maybe a patch could solve the issue if HTC knew what the issue was.

Audio qulity from headphone jack

Just wanted to know if anyone else noticed faint buzzing/scratching/hissing noises coming out of their headphone jack...
(and yes I have tested several headphones/earbuds and tested with my MDRv6's all with the same results. Its definitely the phone not the headphones)
When I insert my headphones there is a quick beeping sound that plays for a second or so then goes quiet.
When music is playing, especially soft music (a particular song was Instant Crush; Daft Punk) there is a hiss in the background, specifically when certain tones play.
It was terribly noticeable right at the beginning of a few songs, especially the one I listed above.
I also have button sound effects enabled. So When I press one of the soft UI buttons it makes a tick noise. However for about 5 seconds after the tick there is a long hiss then silence until I press another button.
The volume of the hissing/scratching noises is directly related to the actual volume of the device and the note playing.
Im on stock build 11c w/root, and I havent found a lot of info about this problem.
Just wondering if anyone has noticed this, or if this is a known issue?
If your phone is warranteed, I would bring it in
The G3 boasts an AMPLIFIED 1 watt sound speaker, which means there is a powered sound processor.. Unless the jack needs to be cleaned, I would lean toward thinking there is a defect in your phones jack, or sound assembly. I think its more than likely a defective jack, especially if there are no sounds like you are describing when headphones are not in use
Yeah the phone is brand new. I think I'm going to RMA....
Sent from my VS985 4G using XDA Free mobile app
I've noticed it. Seems to be worse when charging.
Verizon remotely detected root, warranty voided.
Posted about it here.
http://forum.xda-developers.com/showthread.php?p=57355721
Word of warning before calling Verizon
Sent from my VS985 4G using XDA Free mobile app
nuke235 said:
Just wanted to know if anyone else noticed faint buzzing/scratching/hissing noises coming out of their headphone jack...
(and yes I have tested several headphones/earbuds and tested with my MDRv6's all with the same results. Its definitely the phone not the headphones)
When I insert my headphones there is a quick beeping sound that plays for a second or so then goes quiet.
When music is playing, especially soft music (a particular song was Instant Crush; Daft Punk) there is a hiss in the background, specifically when certain tones play.
It was terribly noticeable right at the beginning of a few songs, especially the one I listed above.
I also have button sound effects enabled. So When I press one of the soft UI buttons it makes a tick noise. However for about 5 seconds after the tick there is a long hiss then silence until I press another button.
The volume of the hissing/scratching noises is directly related to the actual volume of the device and the note playing.
Im on stock build 11c w/root, and I havent found a lot of info about this problem.
Just wondering if anyone has noticed this, or if this is a known issue?
Click to expand...
Click to collapse
Just got my G3 a week ago and didnt use headphones until I read your post, I tested many different songs with different players, stock player, google player, Iheart radio, pandora, etc, headphone sound is crystal clear on mine, I dont get any beeps either like you described, I did notice you need to make sure the jack is pushed in good and tight, I put it in and thought it was all the way in and sound was crappy, pushed a bit harder and it clicked in good and sound was great, do you have a case that may be preventing the jack from being pushed in all the way, I had a phone in the past that this happened to me with, had to cut away some rubber on the jack to make it fit snug, if none of those are the issue, I would look into a warranty claim. I am using the beats audio earbuds that came with my HTC M7 I had before this phone.
kchinth said:
I've noticed it. Seems to be worse when charging.
Click to expand...
Click to collapse
That could be the issue. I know on the 2012 Nexus 7, it's really bad. It's supposedly due to the microUSB port and the headphone jack sharing the same circuit, or some engineering thing like.
Wonder if it's the same or if they didn't shield the headphone jack very well and it's picking up interference from the microUSB port when charging?
I didn't want to leave this up in the air so I figured I would post an update.
I replaced my G3 through Verizon for a brand new unit. My first phone was of an earlier batch (came with the 10b update) the second one was of a later batch and had 11b pre-installed.
Both phones had the same issue. There is a hissing noise/distortion that comes from the headphone jack. Even when not playing music.
I noticed it on other phones too but not anywhere nearly as much. I understand that any audio source is going to have a little background interference but the G3 definitely has a more significant issue than others.
However it seems to be entirely dependant on what headphones you are using.
1st. I tested first with my Sony MDR-v6's which the problem is most noticeable on. Extreme hissing/background noise.
2nd. Then I used a pair of Audio Techina ATH-PRO500's and the problem was almost unnoticeable.
3rd. I also tried my Steel Series Siberia v2's and the problem was again almost completely gone.
4th. I also used my receiver at home. JVC 5.1 channel receiver with RCA speakers and a Kenwood sub, didn't notice the issue at all. However there where some occasional strange popping noises when no music was playing I didn't get on my GS3 or other MP3 player.
5th. Finally I tried the ear buds that came with my Galaxy S3 and the distortion was again totally noticeable with and without music playing.
This is most definitely an issue that totally depends on what headphones you are using not sure if it has to do with sensitivity or impedance (this is what most people think) however it is most definitely an issue. I saw a few threads saying that audio issues were a problem in Android 4.4.2 however LG/Verizon have yet to release a stock base on anything but.
I suppose I could flash AOSP 4.4.4 and see if the problem persists but I don't know if that would even be worth it.
2 phones and 4 headsets later this is starting to seem like either a software or a design issue.
However I have nothing but good to say about every other bit of this phone. Really besides the audio jack top notch all around.
Sent from my Stumped and Bumped Verizon LG G3
I might have found a workaround for this
I have tested 3 LG D855 and all of them have noise/static/high-freq leak from the processor out to the headphones. It might be a faulty design for the headphones amplification stage for headphones (when the headphones logo appears on the status bar). However, when using line level output (the jack appears on the status bar) the problem does not reproduce.
Therefore the workaround I've found is to trick the phone into line level output mode and then plug the headphones. To do this you need to plug in a 3.5mm jack extensor or a 2-to-1 3.5mm Y-adapter with no load, that's it, with nothing connected to it. At that moment, the phone will activate the line level output mode. Only after that you will connect the headphones, and you'll see there are no artifacts on the audio.
That being said, I'm not sure this will work with all kind of headphones as I have only tried with mines that are low-impedance ones, but on those it works perfectly. To be checked if the level of the signal in line mode is enough to drive other headphones.
In any case, it is a shame this happens with a high-end and expensive smartphone. I was hopping this will be fixed in a newer hardware revision but I got two replacements of mine and no luck. I have read somewhere this might be a flaw in Snapdragon 801, as it integrates completely the signal routings but isolates badly highfreq noise from processor stages, etc. etc. but I do not remember where I did read it unfortunately.
I hope this helps!
drondron said:
I have tested 3 LG D855 and all of them have noise/static/high-freq leak from the processor out to the headphones. It might be a faulty design for the headphones amplification stage for headphones (when the headphones logo appears on the status bar). However, when using line level output (the jack appears on the status bar) the problem does not reproduce.
Therefore the workaround I've found is to trick the phone into line level output mode and then plug the headphones. To do this you need to plug in a 3.5mm jack extensor or a 2-to-1 3.5mm Y-adapter with no load, that's it, with nothing connected to it. At that moment, the phone will activate the line level output mode. Only after that you will connect the headphones, and you'll see there are no artifacts on the audio.
That being said, I'm not sure this will work with all kind of headphones as I have only tried with mines that are low-impedance ones, but on those it works perfectly. To be checked if the level of the signal in line mode is enough to drive other headphones.
In any case, it is a shame this happens with a high-end and expensive smartphone. I was hopping this will be fixed in a newer hardware revision but I got two replacements of mine and no luck. I have read somewhere this might be a flaw in Snapdragon 801, as it integrates completely the signal routings but isolates badly highfreq noise from processor stages, etc. etc. but I do not remember where I did read it unfortunately.
I hope this helps!
Click to expand...
Click to collapse
Ive been having the same issue. I have a pair of Shure SE846 which are about 8ohms. I experience the poor audio, especially the noise in the left channel. I find that placing a call and then listening to music removes the left channel static but the sound is still kinda bad. Ill try your suggestion tonight and post back. Just wanted to let you know your not alone.
I despise my G3 because of this. Im looking to get a new phone unless I can fix this.
Nope, my sound is perfect on my high-end Sony over the ear phones. Crystal clear on pure stock G3 .
I haven't noticed any artifact issues on my phone when using headphones, however when I plug it into my vehicle and also plug in the charger that causes everything to go nuts. The USB interference causes a crazy amount of excess noise. I haven't ever actually tried listening to headphones while charging, so in the car is the only time I've ever noticed it. The same issue occurs when I plug in my Galaxy Tab Pro into the aux jack and charge it at the same time, so this is definitely not unique to the G3. I wish all phones had as good an amplifier as my HTC DNA does, I still use that thing for music because the sound is so good.
pitbull8265 said:
If your phone is warranteed, I would bring it in
The G3 boasts an AMPLIFIED 1 watt sound speaker, which means there is a powered sound processor.. Unless the jack needs to be cleaned, I would lean toward thinking there is a defect in your phones jack, or sound assembly. I think its more than likely a defective jack, especially if there are no sounds like you are describing when headphones are not in use
Click to expand...
Click to collapse
I'm having a different audio problem.
With headphones plugged in and listening to music using any player, the right side sound emits distortion/hissing noise at a certain frequencies. When I tested it with plugging a 3.5mm to 3.5mm to an external amp (JDS labs c5) the distortion/hissing noise is completely gone. So it's definitely not a faulty jack
The hissing is evident at the beginning of (first few seconds) Tina Area's Still Running and You set fire to my heart .
I'm testing it with sensitive iem (Westone Um3x).
So does this mean there is a problem with the internal amp of the g3 or more to do with the os bug that can be solved with a custom kernel or update.
Is this a common issue found on all g3s?
drondron said:
I have tested 3 LG D855 and all of them have noise/static/high-freq leak from the processor out to the headphones. It might be a faulty design for the headphones amplification stage for headphones (when the headphones logo appears on the status bar). However, when using line level output (the jack appears on the status bar) the problem does not reproduce.
Therefore the workaround I've found is to trick the phone into line level output mode and then plug the headphones. To do this you need to plug in a 3.5mm jack extensor or a 2-to-1 3.5mm Y-adapter with no load, that's it, with nothing connected to it. At that moment, the phone will activate the line level output mode. Only after that you will connect the headphones, and you'll see there are no artifacts on the audio.
That being said, I'm not sure this will work with all kind of headphones as I have only tried with mines that are low-impedance ones, but on those it works perfectly. To be checked if the level of the signal in line mode is enough to drive other headphones.
In any case, it is a shame this happens with a high-end and expensive smartphone. I was hopping this will be fixed in a newer hardware revision but I got two replacements of mine and no luck. I have read somewhere this might be a flaw in Snapdragon 801, as it integrates completely the signal routings but isolates badly highfreq noise from processor stages, etc. etc. but I do not remember where I did read it unfortunately.
I hope this helps!
Click to expand...
Click to collapse
Hi! This worked perfectly for me but for me instead of tricking the phone into line level output mode, I detaching one side of my headphones before plugging it into the headphone jack then reattached it afterwards. I'm using pair of sensitive iems (Westone um3x rc)
Everything is quit with no distortion, just how it should be!
One thing, is there an option within android or an app that can permanently enable line level mode ever time headphones are plugged in without having to trick it.
If so, I won't have to sent my phone for repair!
Also are there any disadvantages for using line level with headphones?
Fungus999 said:
Hi! This worked perfectly for me but for me instead of tricking the phone into line level output mode, I detaching one side of my headphones before plugging it into the headphone jack then reattached it afterwards. I'm using pair of sensitive iems (Westone um3x rc)
Everything is quit with no distortion, just how it should be!
One thing, is there an option within android or an app that can permanently enable line level mode ever time headphones are plugged in without having to trick it.
If so, I won't have to sent my phone for repair!
Also are there any disadvantages for using line level with headphones?
Click to expand...
Click to collapse
Using line out shouldn't make any difference on audio quality. It only disables the remote (buttons and microphone).
Would also really like a way to force the line-out mode. Btw, does this affect all G3s? Cause right now I'm not sure if it's worth the hassle of replacing it.
sulkie said:
Using line out shouldn't make any difference on audio quality. It only disables the remote (buttons and microphone).
Would also really like a way to force the line-out mode. Btw, does this affect all G3s? Cause right now I'm not sure if it's worth the hassle of replacing it.
Click to expand...
Click to collapse
I know but some how using line out causes the hissing from the right side to go away completely. Strange huh
Are you also having this problem?
I also don't want to return mine if it exists in all g3s and there's a easier work around.
Yea same thing. I have artifacts in the left channel except when I manage to force the phone to recognize the headphones as line-out. I did this with the adapter to test it and it's impractical if not impossible to use the same adapter all the time.
I'm gonna try doing this right this moment to see if it works: http://forum.xda-developers.com/lg-g3/help/hissing-noise-left-ear-playing-music-t2804065/page17
sulkie said:
Yea same thing. I have artifacts in the left channel except when I manage to force the phone to recognize the headphones as line-out. I did this with the adapter to test it and it's impractical if not impossible to use the same adapter all the time.
I'm gonna try doing this right this moment to see if it works: http://forum.xda-developers.com/lg-g3/help/hissing-noise-left-ear-playing-music-t2804065/page17
Click to expand...
Click to collapse
I don't use earphones with a volume remote or microphone so that's not a problem.
It could be more to do with the increase in output impedance but I might be wrong cos the volume level is identical to headphone out.
I'm also getting a lot of static background noise but it disappears after making and hanging up a call as mentioned in a thread.
But yeah a permanent fix by forcing it into line out or doing some changes in kernel would be much more convenient
Fungus999 said:
I don't use earphones with a volume remote or microphone so that's not a problem.
It could be more to do with the increase in output impedance but I might be wrong cos the volume level is identical to headphone out.
I'm also getting a lot of static background noise but it disappears after making and hanging up a call as mentioned in a thread.
But yeah a permanent fix by forcing it into line out or doing some changes in kernel would be much more convenient
Click to expand...
Click to collapse
Great news! I just tried the fix from that thread and it worked. Here's the post: http://forum.xda-developers.com/showpost.php?p=59601465&postcount=150
I'm using stock rom which had 3 mixer xml files and I edited 2 of them, mixer_paths.xml and mixer_paths_qcwcn.xml. Also, instead of changing the value to 0, I deleted the entire line as it was suggested later in the thread.
The artifacts/noise in the left channel are gone!
sulkie said:
Great news! I just tried the fix from that thread and it worked. Here's the post: http://forum.xda-developers.com/showpost.php?p=59601465&postcount=150
I'm using stock rom which had 3 mixer xml files and I edited 2 of them, mixer_paths.xml and mixer_paths_qcwcn.xml. Also, instead of changing the value to 0, I deleted the entire line as it was suggested later in the thread.
The artifacts/noise in the left channel are gone!
Click to expand...
Click to collapse
But mine is stock on stock Lollipop via official update and with the hiss coming from the right side.
Please excuses my ignorance but I know nothing about accessing and editing a ROM.
How do I get into the rom and into the file called system/etc"?

[Mod] Weak microphone quality: Split up BT and Sys; Add external microphone(s)

Specific to KGL
I've had the KGL variant for a couple of weeks. Since I've had my share of Chinese Android devices of all sorts - I kind of knew what to expect in terms of software.. so I wasn't really disappointed BUT... the hands free in this unit was simply unusable... After getting my wife totally upset and my friends pissed at me for calling them using the unit I knew something had to be done.
So I took it apart.
Being that I'm skilled in electronics and pretty much hands-on, I figured out the problem pretty fast. Or should I say "problems" in plural?
Let me start by saying that if you have the KGL variant and suffer from extreme noise bleeding into the mic - there is no software workaround. You either need to send it back and get something else or open and modify it like I did.
Second - the hardware in this thing is of such low quality, and the design is so bad, it makes me cry. I estimate the production cost of this unit is under $50. Pretty pretty low... even for Chinese stuff.
So.. what's the story with the mic noise, you ask? very simple. The mic signal from the front panel is routed unshielded from a small PCB attached to the panel, via 3 PCBs and 2 ribbon cables, for over 15" until it arrives at the Bluetooth module MIC input. On the way, it picks up so much electrical noise and interference it's almost a miracle that you hear anything but static noise. When an external mic is plugged it, the front panel mic is NOT disconnected. Both are electrically connected in parallel which is unheard of (very bad practice). The Bluetooth module is thus responsible for MIC bias and preamp. The BT module is of unknown source and it's hard to tell what quality to expect there (not much, as we all know). Noise cancellation? echo cancellation? forget it!
Now - we know android needs an audio input - we can have some voice activation on the unit, right? so how is it done? simple! the signal from the BT mic input line is run back to the front panel and into a Wolfson CODEC. Just like that... so that the Android audio in would also suffer from the above issues.
This also explains the exact nature of the unit's BT implementation - the handsfree is not done by the Android - it's completely handled by the BT module. BT module has MIC in, AUDIO out (that goes to the BD37534 audio mixer chip) and RS232 control signals that communicate with the Android BT application for User Interface (probably via AT commands).
When you run an Android app that uses audio input - it comes from the Wolfson CODEC but it's essentialy the same lousy MIC signal that the BT also gets.
BUT!!!
I've made some modifications and lo and behold - I can make a good quality phone conversation now! and the google apps have somewhat better performance too... but it did require me to completely mess up the internal wiring and obviously void the priceless warranty
So after I've figured it out - I decided I needed to do the following:
- Give up the option to work with two mics at the same time and opt for the external mic only for voice calls
- Cut and bypass the original traces since they pick up so much noise
- Add a separate input jack for the external microphone since it was not feasible to cut the lines going into the original one
I started by installing the extra jack on the rear panel. Then I removed a jumper 0ohm resistor at the MIC input to the BT module, disconnecting the MIC input from the circuit. I ran a piece of shielded wire from the new jack to the MIC input signal pin ON the BT board. That completed the hands-free modification.
In order for the Android to have some audio input, I then moved to the front panel, and first installed a 0Ohm jumper that was missing by the WM8731 CODEC. This resistor connects the MIC BIAS pin to the MIC input - it is required when using an electret microphone. I then made a cut in the trace from the front panel microphone to the small PCB connector, and ran a piece of shielded wire from the mic terminals to the WM8731 MIC input.
Now the front mic is only for Android (voice commands etc) and the external mic serves hands free.. I could have probably added some smarter electronics but I don't think it would have added anything to the usage experience.
Let me know if anyone is interested in some pictures I've taken and I will upload.
Crappy piece of equipment but at least now it works.
All the best,
Nir
...
Moderation note form dark alex:
these are pictures which belong to dnts' tutorial and research
harlequin69 said:
Great work and thank you for sharing. I can follow most of what you did there except for adding the jumper to the CODEC due to electret mic use, do you have any pics of this? also why did you choose to use both mics in the end? would it not be better to use the external mic for both BT and android?
Click to expand...
Click to collapse
Regarding external mic for both BT and Android - here is the catch - you need to add a buffer (amplifier circuit) to the mic signal before sending it to two destinations (BT and CODEC) otherwise you will get that awful noise back. The microphones have a high output impedance which makes them prone to electrical noise. Even if you run them using shielded wire to two locations - you will be picking up noise via the ground signal due to the high impedance.
So to keep things simple (for now) I opted for separate mics, with the higher quality one for calls.
As for the required jumper, I attached a pic. The red circle around the empty pads shows where you need to put a short. The green line shows where you would connect the internal mic. Either pad works (they are shorted on the PCB).
Nir
Specific for KGL
From the top of my head.. sorry for that.. Please use pics in my previous posts.
1. Remove unit. Remove screws holding front panel to the chassis (this varies from one car model to another - mine is KIA Sportage).
2. Carefully lay down front panel. Take notice of the two ribbon cables and don't pull them
3. Remove chassis top cover (2 side screws and one screw on the back).
4. Remove optical drive - 4 screws hold it in place. Carefully disconnect ribbon cable.
5. Install 3.5mm mono jack on the rear panel - 2 holes are available for that (those reserved for DTV antenna). Wire a piece of shielded conductor to the jack, shield going to the part touching the chassis (sleeve) and internal conductor going to the "tip" contact.
6. Locate BT module. It will be at the right side of the chassis (eyeing from front), close to the front end of the PCB.
7. Near the BT module, on the main PCB, locate the component marked "C32". It should be marked "0". Remove it. This is a jumper connecting the BT MIC input to the microphones.
8. Connect the other end of the shielded conductor to the BT module to the pin labeled "MIC+". Do if from the back size of the module. Secure the shielded wire in several places so it doesn't loose up over time.
At this point, the external mic will be the only source for BT audio in. It should (obviously) connected to the new jack we installed.
9. Locate the PCB holding the microphone to the front panel. Locate the PCB trace from the lower microphone terminal (the other terminal is connected to the ground plane of the PCB). make a cut to that trace.
10. Prepare another shielded conductor. connect shied to the mic terminal that is grounded (top one) and the internal conductor to the terminal connected to the trace we just cut. (please see picture titled "front mic").
11. Locate WM8731 CODEC chip. Identify missing "R45" pads (only vacant pads near the WM8731 chip). Make a jumper using some solder and a piece of wire. This calls for delicate soldering.
12. Connect other end of mic conductor to the pad of R42 and R45 further away from WM8731 (please see picture titled "CODEC connection")
13. Put everything back together - start with ribbon for the optical drive, 4 screws for the drive, top cover of chassis and front panel. Make sure, before securing the front panel, that the two ribbon cables are well connected and have not moved or shifted inside their connectors.
14. Cross fingers and connect back to power.
You're done.
Nir
Relax, don't do it!
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Specific for JY
tomc99 said:
I did find a capacitor linking the BT module on my JY unit, but removing it didn't give me the results I needed, so that's when I moved to cutting the leg on the BT module.
I seem to get some bias at the microphone socket - maybe a little low, from memory around 1.7 volts, but no audio whatsoever.
A little bit of a mystery to me is that after cutting the leg on the module the internal mic is now virtually clear of all buzzing that was evident beforehand.
I may spend a few hours this weekend and set it up on my bench power supply and have a better play with it.
Tom.
Sent from my GT-N5100 using XDA Free mobile app
Click to expand...
Click to collapse
I have a G2110 model( which is a Joyous JY) that suffered with bad buzzing and echoing when using hands free. In stock form testing internal MIC with sound recorder there was no issue. Recording was clear. When I made hand-free call buzzing and reverb sound occurred. I read over and over about the external mic modification and decided to try it. Opened up HU and located C32 which was actually located toward the front center of the unit. I removed it and tested and same issues occurred. I then reconnect C32 as it was apparent that this was not the correct one on this board. I then took advise of previous posts that the cap should be located somewhere near the Bluetooth module so did continuity checks from the + of internal MIC to the caps near the Bluetooth module. I found C102(located seemed to connect to internal MIC on one side and the Bluetooth Mic + on the other. I decided to remove that and test. After removal internal MIC still functioned but hands-free was dead. I am assuming that this was the correct cap that needed to be removed. I did not do anything to the legs of the actual module. I did add an external jack to the backside of the module per the previous posts on how to add external MIC. After I completed the task I tested and the two appear to be separated and the hand-free external seems to function. I still get a little reverb noise but nothing like it was. I am not an electrical guru so I'm not sure if what I did is correct but it seems to have helped somewhat. I took some pics.
Ok...I need to do this as got that horrible Mike thing going with Bluetooth..
I still need to get my head around the best way to do it..
Best way is going to have to print this thread and work out a plan of attack..
At the moment I have not plugged in the mike at back but been using the front Mike for Bluetooth calls..and of course no one can hear me..
As for Bluetooth coming out to speaks..that all works fine..
Sent from my SM-G900F using Tapatalk
dgcruzing said:
Ok...I need to do this as got that horrible Mike thing going with Bluetooth..
I still need to get my head around the best way to do it..
Best way is going to have to print this thread and work out a plan of attack..
At the moment I have not plugged in the mike at back but been using the front Mike for Bluetooth calls..and of course no one can hear me..
As for Bluetooth coming out to speaks..that all works fine..
Sent from my SM-G900F using Tapatalk
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Click to collapse
I'm with you pal. This is pretty confusing, especially when you take into account the different models of the head units. I want to improve my mic, but I don't want to mess up and make it worse.
If anyone with a joying unit wants to put together an idiots guide to this mod, I would send a huge thank you your way. [emoji106]
Sent from my iPhone using Tapatalk
tdopko said:
Specific for JY
I have a G2110 model( which is a Joyous JY) that suffered with bad buzzing and echoing when using hands free. In stock form testing internal MIC with sound recorder there was no issue. Recording was clear. When I made hand-free call buzzing and reverb sound occurred. I read over and over about the external mic modification and decided to try it. Opened up HU and located C32 which was actually located toward the front center of the unit. I removed it and tested and same issues occurred. I then reconnect C32 as it was apparent that this was not the correct one on this board. I then took advise of previous posts that the cap should be located somewhere near the Bluetooth module so did continuity checks from the + of internal MIC to the caps near the Bluetooth module. I found C102(located seemed to connect to internal MIC on one side and the Bluetooth Mic + on the other. I decided to remove that and test. After removal internal MIC still functioned but hands-free was dead. I am assuming that this was the correct cap that needed to be removed. I did not do anything to the legs of the actual module. I did add an external jack to the backside of the module per the previous posts on how to add external MIC. After I completed the task I tested and the two appear to be separated and the hand-free external seems to function. I still get a little reverb noise but nothing like it was. I am not an electrical guru so I'm not sure if what I did is correct but it seems to have helped somewhat. I took some pics.
Click to expand...
Click to collapse
Hi,
I did my soldering too. I found that my microphone is on pin connection infront of BT module and it is connected through c102 jumper. So i cut that microphone and solder it on back of BT module on mic+ and mic-. Problem is that when I call the internal mic is on and external is not working or is off. I am not sure if the external mic was ever on and I did talk thorough internal mic. Can you just tell me what did you solder to what?
Thank you
dsa8310 said:
I have followed the microphone recipe in post #3964, and here is my experience:
Separation between the Android internal mic and the hands-free external mic is definitely a great solution. With the external mic connected directly to the BT module (and capacitor C32 removed) people tell me that they cannot say that I am using hands-free - the call quality has become that good.
Connecting the internal mic directly to the CODEC chip - not a good idea, unless you have proper tools and you know what you are doing. In fact, Skype and Google Search, both work beautifully with no need for any further change.
Beware, the image in post #3971 , detailing where to connect the mic IS WRONG! The mic should be connected where the strap between the two empty pads is made (in order to have the mic powered with chip's bias voltage). Only the pad at the left end of the green line is OK for mic connection.
I had to redo the soldering, after looking up the chip's pin-out, and this was the end of my empty pads... (overheating with improper tools). With no bias voltage, I could no longer connect the mic directly.
And since I had already cut the mic trace on board, I couldn't reconnect my internal mic, other than using a shielded wire which went outside the unit and into the available external mic socket. Thanks Huifei for your thoughtful design!
And now, my internal mic, even wired through the external mic socket, works perfectly for Android. I got lucky...
So, my advice, stick to the first part of the recipe, it's a must for phone quality hands-free calls, but relax, don't do it - the second part calls for trouble and seems unnecessary, really.
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Click to collapse
Thank you all for the very useful information that you give us every day,
I am owner of a KLD. Specifically a Witson A7047.
I ask you please to be able to summarize in detail the operations to be done in order to make the modification of the microphone.
As I understand, I should find the capacitor C32 and remove it.
I miss, however, the passage for connecting external microphone.
Excuse my trivial question, but understand little of electronics and I have to carry the equipment by the technician. Obviously I will have to explain what to do.
Thanks for the answer
hello, i'm also using a joying head unit and i have the same problems with my mic. Until now i only used the unit internal mic and the external one is not even connected. Has any of you managed to do any mod (not requiring too much of electronics skills since i dont have any)
Aender84 said:
hello, i'm also using a joying head unit and i have the same problems with my mic. Until now i only used the unit internal mic and the external one is not even connected. Has any of you managed to do any mod (not requiring too much of electronics skills since i dont have any)
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Click to collapse
The external mic is better than the internal, but it is still not great. It makes a lot of electrical noise on the other end if the phone call. There are some instructions for mic mod here, but I have also read that the joying units are a little different than those details here. I haven't tried it yet, so I can't help any more than that.
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But is there any way to still use the car existing mic? My car already had a stock Bluetooth installed so I also heve the mic for it
Aender84 said:
But is there any way to still use the car existing mic? My car already had a stock Bluetooth installed so I also heve the mic for it
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Click to collapse
Not that I am aware of. It would have to be routed through the Android unit somehow. Otherwise it wouldn't switch automatically when you receive a call. That is if it can even be done at all. I suspect that the Bluetooth module was in the stock radio unit.
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I believe is a matter of wiring. The Bluetooth unit was not embedded in the original headunit, so probably there is a way to do it.
Aender84 said:
I believe is a matter of wiring. The Bluetooth unit was not embedded in the original headunit, so probably there is a way to do it.
Click to expand...
Click to collapse
Are you sure about that? Maybe yours is different than mine. I have the jbl, non-nav unit. I can't access anything to do with the Bluetooth now that I've removed the head unit.
If you're only saying that he can wire the original microphone into the Android unit, that may be possible. It's the same as wiring any external microphone I guess.
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I have not possibility to hardware mod.
No software mod can help me?if i buy a bt mic?or bt handfree kit?
Inviato dal mio SM-G920F utilizzando Tapatalk

Just got it - heaphone aux problem...again

I use an aux cable in my car to listen to music and podcasts.
when starting spotify i experienced incredible amounts of static, no matter what volume both the phone and car volume were set at.
Anybody else experience this?
Experiencing this in my work truck, will check my car after work
Sent from my LG-H830 using Tapatalk
Works fine in my car. Must be something else
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napafats said:
Works fine in my car. Must be something else
Sent from my LG-H830 using Tapatalk
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Might be the worst static and fuzz ive ever experienced through a phone. Dont know what to do.
Any updates on this?
Mine comes out with an incredibly small amount of movement. Anyone else have this issue?
Nvm I just was being too easy on it. Requires a lot of pressure relative to anything else I've had for it to lock in.
Also you guys should dip a q-tip in rubbing alcohol and clean out your cars and phones headphone jacks. Especially in a work truck I imagine there's significant dust build up in there.
....cable
I found this too, even the headphones supplied need a fair amount of force to connect - at least they won't be pulled out so easy!
1 Maybe RF from cell communication leaking into audio or power cable.
2 Try with phone Not plugged into car power (I assume you run this with charger cable connected).
3 Try with better quality aux cable, maybe one that is shielded.
No fix. so aggravating.
Mine are flawless.
I just got the g5. Same issue. Tried multiple cables. Headphones work fine but not the aux cable
Just got my G5 a few days ago and I noticed this too.
In the car using a downloaded playlist on spotify and got terrible static noises (haven't tried any local music files as I don't use any!)
Sent from my LG-H850 using Tapatalk
I tried it in another head unit and it works.
Aux cable works in my Alpine but not in the Kenwood.
Ok guys and gals. I've been dealing with this for a bit and I found a fix of sorts. First off, two G5s (a buddies and mine) both had static in my car, but no static in his car or my mother's car. The difference being is that I have an aftermarket JVC player (removable face plate, auxiliary jack in front). The other two cars had factory stereos. I was guessing it was an aftermarket thing. Weird, I know, but that was the only commonality. Even more odd was that out of four phones the G5 was the only one having the hissy fit.
On Reddit some people were fixing this problem with a "ground loop isolator". It's basically this little noise filter device that plugs in the audio jack. Maybe $15 on Amazon. Anyways, I was about to order one, but before that I decided to take the head unit out of my car to see if any wires were loose. No wires were loose, but what I did find was an alternative 3.5mm jack in the back of my stereo. I'm sure not all stereos have a second port, but there's a decent chance. My particular head unit isn't what you'd call fancy by any means and it has one. So I plugged it in the back 3.5mm port and wouldn't you know, crystal clear sound!! I was so happy when it worked! Now instead of putting my stereo to "auxiliary" for the front port. I have to put it on "bt audio" to access the rear one. (whatever bt audio means, who knows, but it works).
So that's basically it, find out if your car stereo has a secondary 3.5mm port in the back and give it a shot. I didn't realize it at first, but right next to the front auxiliary port it actually says dual auxiliary/audio port. It could be an easy way to find out. As for rerouting the cord. I have a little pocket directly under my radio. There was a tiny hole in the back of the pocket/tray that I put the wire through. It looks cleaner than having it stick out from the faceplate of the radio any way.
If your stereo doesn't have a second 3.5mm port in the back You may want to check out a "ground loop isolator" from Amazon.
Good luck folks. Peace.
Not sure if could post links to the isolator. I'll give it a try.
Kresk - Here is the part that will boggle your mind with this issue. Go and play the stock LG sound file on the phone (The "High Quality" audio track). Once that plays, the static stops. Then switch to your regular music app - I use Spotify - and the music plays static free until the built in music app closes in the background. Then all the static comes back. If there was some way to force the phone to stay in whatever mode it uses for the High Quality audio track, it could be a great fix.
I've also found that there are three different "modes" of static I get on my phone too
1) Static Free
2) Low level of background static, volume independent (volume stays the same low background noise)
3) High level of static, volume dependent (Higher the volume, more static)
Typically when I do the thing where I get it into High Quality audio mode or whatever its using, I get 2 when immediately switching to Spotify. If I lock and unlock my screen, it goes to 3.
I'm going to go and try to plug into the "BT Audio" port on the back of my JVC head unit and see if it works. Will report back on it. I also have a ground loop isolator coming in the mail tomorrow, so I can give an update on that as well.
~PubstarHero
You might need a Ground Loop Noise Isolator, such as this: https://www.amazon.com/Mpow-Ground-Isolator-System-Stereo/dp/B019393MV2
I am thinking of getting one for an issue similar, but not the same as yours.
Same issues, in general. Static on most aux cables, and in my case some headphones don't work at all. My higher-end earbuds work flawlessly though, so go figure. Not sure what to do about it other than the ground fault isolator, though I was about to start looking into a Bluetooth-to-aux module.

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