Low pass and high pass frequency - How to setup cut off? - MTCB Android Head Units Q&A

Hello,
I have just bought and connected in my car radio with android. At this moment I have only one BIG problem. Front speakers (mid-range and tweeters) are connected to radio with ISO and subwoffer with amplifier through RCA. The problem is that I would like to cut off low frequency on the front speakers connected with ISO. Is there a possibility to do that with software and if yes then what software it is?
Regards,
Adrian

Not with any software known to me, however why do you not just use a high / low converter?

I guess that I will just buy another amplifier for the front speakers.

Related

Bluetooth headphone speaker switch?

My insignia(cheapo!) bluetooth headset has broken. I was wondering if anyone had any experience of switching out the speaker or switching out the bluetooth chipset into a new headphone form factor. It seems as if it wouldnt be too hard to do. I am not sure how the driver would work out since the speaker inside the insignia set says it is 32 ohm and 0.5 mW. This seems kinda tough to match. I would love to get some real quality audio out of this thing. Thanks!

Review: Hizpo 7.1.2 for GM Vehicles, PX3, MTCE_XRC_V2.75_1

I just received a Hizpo 7.1.2 unit made for GM Vehicles 2007-2012(depending on model). I Installed it in a 2007 GMC Yukon XL Denali w/ Bose, XM, factory rear camera, Onstar, and factory rear entertainment. The goal was to retain all vehicle functionality except Onstar and XM.
The Unit: https://www.amazon.com/gp/product/B077SBX8CG/ref=oh_aui_detailpage_o00_s01?ie=UTF8&psc=1
Android 7.1.2, CPU: Rockchip PX3 Cortex A9 Quad Core 1.6GHz, Memory: 16GB, RAM: 2GB
MCU: MTCE_XRC_V2.75_1
I attached pics of the specifics.
The Good:
1. Very fast. The unit seems quite responsive so far. I have only installed the Youtube app and Car Launcher.
2. Screen Quality is fantastic. No issues so far but I need to attempt to watch some HD files from an SD card
3. WiFi download speeds are fairly quick, no complaints
4. Bluetooth Audio quality is great.
5. Radio Quality is great, no excess noise and range seems to be on par with stock system
6. BT internal Mic seems to work OK. My wife said I sounded like I am in a car so pretty much normal.
The Bad:
1. Instructions for install are non existent. It is supposed to be plug and play but initially I couldn't figure out why I couldn't get any audio. Turns out I had to plug two random blue "amp-con" wires together.
2. The dB output is set to "0" from the factory. This makes volume level 1 waaaay to loud with the Bose system. Thanks to a few posts on these forums, I was able to get in to the factory settings(code 126) and lower the output to a reasonable level and this worked perfectly. Sound quality is still fantastic after the change.
3. There is a very light static noise from all speakers. Some have suggested this is just common because of junk internals or poor wiring.
4. Every click of the Volume knob gives a light audible thumb noise. I am not sure if this is due to something internal or maybe I need to tape up every connection in the back to ensure nothing is touching.
5. Wifi antenna is bulky and cannot be used on my model unless I cut the plastic behind the dash. I left the antenna off and I can hit my phones hotspot without any issues.
6. CANBUS settings at the factory were at none. I had to change it to GM before it would recognize the volume buttons on the steering wheel but those do work.
Things left to test/figure out:
1. Factory Rear Entertainment. Now working after playing with the RCA's to find which ones did what. No adapter needed but still trying to figure out how to force the rear screen to show anything playing on the main LCD and not just DVD.
If anyone has any ideas on the static, I am all ears. I will update this with my findings as I personally scoured this forum for info on Hizpo units and found nothing. I know Hizpo is just a seller but still without the right info its almost impossible to know what MCU your unit will be. I hope this will help others in the future.
Where should I look for ROMS to put on if I can get the static fixed? Thanks!
Krmnnghia said:
I just received a Hizpo 7.1.2 unit made for GM Vehicles 2007-2012(depending on model). I Installed it in a 2007 GMC Yukon XL Denali w/ Bose, XM, factory rear camera, Onstar, and factory rear entertainment. The goal was to retain all vehicle functionality except Onstar and XM.
The Unit: https://www.amazon.com/gp/product/B077SBX8CG/ref=oh_aui_detailpage_o00_s01?ie=UTF8&psc=1
Android 7.1.2, CPU: Rockchip PX3 Cortex A9 Quad Core 1.6GHz, Memory: 16GB, RAM: 2GB
MCU: MTCE_XRC_V2.75_1
I attached pics of the specifics.
The Good:
1. Very fast. The unit seems quite responsive so far. I have only installed the Youtube app and Car Launcher.
2. Screen Quality is fantastic. No issues so far but I need to attempt to watch some HD files from an SD card
3. WiFi download speeds are fairly quick, no complaints
4. Bluetooth Audio quality is great.
5. Radio Quality is great, no excess noise and range seems to be on par with stock system
6. BT internal Mic seems to work OK. My wife said I sounded like I am in a car so pretty much normal.
The Bad:
1. Instructions for install are non existent. It is supposed to be plug and play but initially I couldn't figure out why I couldn't get any audio. Turns out I had to plug two random blue "amp-con" wires together.
2. The dB output is set to "0" from the factory. This makes volume level 1 waaaay to loud with the Bose system. Thanks to a few posts on these forums, I was able to get in to the factory settings(code 126) and lower the output to a reasonable level and this worked perfectly. Sound quality is still fantastic after the change.
3. There is a very light static noise from all speakers. Some have suggested this is just common because of junk internals or poor wiring.
4. Every click of the Volume knob gives a light audible thumb noise. I am not sure if this is due to something internal or maybe I need to tape up every connection in the back to ensure nothing is touching.
5. Wifi antenna is bulky and cannot be used on my model unless I cut the plastic behind the dash. I left the antenna off and I can hit my phones hotspot without any issues.
6. CANBUS settings at the factory were at none. I had to change it to GM before it would recognize the volume buttons on the steering wheel but those do work.
Things left to test/figure out:
1. GPS. I have't wired up the antenna but will do so this week.
2. Rear Camera. It turns on when I go into Reverse but I have not figured out how to use the factory camera with it. I have the Metra BACKUPCAM adapter on order but given what my plugs were used behind the factory radio, I cant tell where the original plug is on the vehicle
3. Factory Rear Entertainment. Rear ceiling monitor turns on when car is on but I have no video back there which I knew would happen. I have the GMRSAV adaper on order to solve this but again, given what my plugs were used behind the factory radio, I cant tell where the original plug is on the vehicle
If anyone has any ideas on the static, I am all ears. I will update this with my findings as I personally scoured this forum for info on Hizpo units and found nothing. I know Hizpo is just a seller but still without the right info its almost impossible to know what MCU your unit will be. I hope this will help others in the future.
Where should I look for ROMS to put on if I can get the static fixed? Thanks!
Click to expand...
Click to collapse
I have read over and over that some head units have horrible grounding paths. If you are using RCA jacks, watch youtube videos on grounding the RCA jacks.
If not using RCA jacks, placing a ground wire on the chassis, or even don't use the factory ground.
Another thing is keep reducing the factory radio volume settings as you started doing. You may be picking up noice from the radio IC.
LET ME KNOW
yellaboyla said:
I have read over and over that some head units have horrible grounding paths. If you are using RCA jacks, watch youtube videos on grounding the RCA jacks.
If not using RCA jacks, placing a ground wire on the chassis, or even don't use the factory ground.
Another thing is keep reducing the factory radio volume settings as you started doing. You may be picking up noice from the radio IC.
LET ME KNOW
Click to expand...
Click to collapse
Thanks for the suggestions! I took the wiring out and am going to tape up and cap anything that is exposed metal to ensure nothing is touching anything it shouldn't. Fitting all this stuff back in is tough. I will first try to ground the chassis. I can't ground the rca's as there are no female jacks on the radio itself. The cables come out and connect outside the unit.
UPDATE:
1. Rear Camera works flawlessly with the Metra BACKUPCAM adapter.
2. Factory Rear Entertainment works WITHOUT the GMRSAV adapter. Because there aren't really any instructions, I just started up a DVD and started plugging in Video feed lines until I found the combo that works. Unfortunately this is still only when I select DVD on the unit.
Someone please tell me the ROM geniuses have figured out a way to mirror everything to the rear monitors? I would love to play Youtube videos for my son in the back.
Next up is cutting some plastic behind the dash to be able to use the Wifi antenna and GPS antenna. I wanted to avoid this but the GPS antenna output is just in the wrong location so we cut!
UPDATE:
Cut the plastic out behind the deck.
Was still very tight fit but the wifi antenna and gps plug in fine now.
Wifi range is very good. Picking up signal from peoples houses as I drive by. GPS is very good. The stock iGO app seems to be worthless or I don't fully understand it. It can't seem to locate POI. I ditched it and went with Sygic which runs smooth and works with the factory GPS antenna without issue.
I have tried several suggestions to fix the static issue like grounding the head unit case, adjusting the brightness(apparently some folks get feedback from the LCD), adjusting all factory volume levels as low as they go. Nothing has fixed it.
I have same static click on volume knob. I have tried to adjust any volume seetimgs, but doesn't seem to help.
My rear screens worked on initial install, but now, I get no display out of them. I also want the IR headsets to work as they are not.
I agree about the screen mirroring option. But I habe tried youtubeTV and it was not compatible. Netflix wouldnt download (figured non compatible) so not sure screen mirroring to rear deop downs really matters.
are you having any trouble with bluetooth streaming on a2dp sounding awful?
How did you get Sygic to run off SD card . Are there instructions in a forum somewhere? Get Sygic to run on your Android and then copy to SD card?? and help would be appreciated. My Hizpo is using IGO PRIME , it ok , but could be better.
Hi, I cannot get signal in the radio, I have bought a antenna adapter and no different, do I need to connect the wire labelled amp up to anything?? This is just unconnected at the moment as didn’t know where to connect it too?
Thanks
Hi
Can please share the canbus option selected in factory settings.
Thanks.

Speakers Noise on Erisin android PX5 HU

Hello,
I have an other problem, i have noise in the speakers like when i accelerate, the sound of the engine speed appears on the speakers !
All is ok between the HU, just i have 5/6 RCA that is not connected... Is it possible that is this RCA the problem ? What can i do please ?
Someone can tell me what can i do ?
Thank you !!
If it’s like a wining noise that changes with the revs, that’s usually caused by poor earth connection.
Sent from my iPhone using Tapatalk
Earthing issue, alternator whine, or just bad insulation on your speaker wires. Look at some isolators and noise filters.
it may be an issue with the am/fm antenna, try disconnecting and see if you have speaker wine then. If theres no speaker wine when the antenna is disconnected, get an antenna noise filter
skezza said:
Earthing issue, alternator whine, or just bad insulation on your speaker wires. Look at some isolators and noise filters.
Click to expand...
Click to collapse
Getting isolators, noise filters or suppressors is just papering over the cracks so to speak. They do get rid of the noise but they also reduce your sound quality. It’s better to find the problem and fix it rather than just buying noise filters etc.
Id tape up all the connections behind the unit, check all the ground connections, or if your car has a factory amp it could be that the amp isn’t getting any power so this is one of the side effects that you see. I have an Audi A3 with Bose amp and this is one of the problems you get with these units if there is no blue amp cable supplied with the speaker cables to be able to turn the amp on.
ab1702 said:
Getting isolators, noise filters or suppressors is just papering over the cracks so to speak. They do get rid of the noise but they also reduce your sound quality. It’s better to find the problem and fix it rather than just buying noise filters etc.
Id tape up all the connections behind the unit, check all the ground connections, or if your car has a factory amp it could be that the amp isn’t getting any power so this is one of the side effects that you see. I have an Audi A3 with Bose amp and this is one of the problems you get with these units if there is no blue amp cable supplied with the speaker cables to be able to turn the amp on.
Click to expand...
Click to collapse
I agree. Papering over the cracks is a perfect description. Another decent saying is needle in a haystack.
Come back in 12 months when you still haven't got rid of it. These things can be a nightmare to solve.

Noise from my brand new Dasaita PK5 whenever wifi data is flowing...

I installed this unit in wife's 2018 Highlander today. It sounds great if wifi is switched off, or if it's on and no data is flowing. I am using Network Mini to monitor data, and as soon as data is going up/down, the crackling starts.
I've reached out to Dasaita and am awaiting a reply
I have grounded the black wire with the ringlet directly to the frame but it makes no difference. I have NOT grounded the radio chassis yet. Also the noise goes away when the unit isn't crammed into the dash. When all the wires are in close proximity to radio is when it picks up
Anyone seen this issue. Love the radio otherwise...
Video:.
https://youtu.be/NhSzLh7CD_0
Wow - that's REALLY bad... I'm starting to get a little fed up with the interference noises from my Eonon MTCE-WWW unit as well. I don't have any issues when using the internal amp, but if I connect to an external amp with the line-out RCAs, I get interference from USB devices, the LED backlighting on the unit, etc. It's shame becuase I love the idea of an Android unit, but not sure I can deal with the subpar quality issues....
Going to try connecting to my amp via speaker-level outputs next and see if that helps at all.
Do you have a stock or aftermarket amp in your vehicle?
Cracks and noises for me as well with my Belsee BP3 PX5 unit.
For me too the noises seem to fade away when I turn off WiFi.
I upgraded the firmware of the unit with a Cs-x sound mod one (there's an recente one for Dasaita too) and it seem to have reduced the issue
https://forum.xda-developers.com/an...ent/mod-cs-x-mod-mtcd-e-mcu-firmware-t3816042
Maybe you can check this out ?
TheDiB said:
Cracks and noises for me as well with my Belsee BP3 PX5 unit.
For me too the noises seem to fade away when I turn off WiFi.
I upgraded the firmware of the unit with a Cs-x sound mod one (there's an recente one for Dasaita too) and it seem to have reduced the issue
https://forum.xda-developers.com/an...ent/mod-cs-x-mod-mtcd-e-mcu-firmware-t3816042
Maybe you can check this out ?
Click to expand...
Click to collapse
I suppose I could try updates, but I don't hold out much hope given that the problem seems to be related to proximity to the wifi antenna. It did this on the stock rom, as well as the Hal9k variant.
I'll update this thread if I manage to find an improvement.
The alternate sound-patched MCU's didn't make any difference whatsoever on my Eonon MTCE-WWW unit. I tried both the cs-x version and the wazdio verion. Same noise-related issues. You may help "hide" them a little by turning down the pre-amp value, but you can also do that with the stock MCUs, under the Factory Settings "Voice" tab.
To put it simply, I think they just use low-quality components with limited R&D - which is why these units are so inexpensive compared to more premium brands of plug-and-play units like Rosen, Dynavin, etc (they run WinCE though).
If using speaker-level outputs on the Eonon doesn't help in my case, I'll probably be going back to a WInCE unit, just becuase they seem to have much higher-quality audio components (better DAC's, 4V pre-outs, BBE processor, real 9-band EQ, time-delay, etc). I was really looking forward to an Android head-unit, but I'm just not willing to sacrifice sound quality to get the Android interface. Viper4Android helps a LOT in terms of sound-quality, but it can't help with the noise-related issues, which are more of a hardware thing...
Maybe some day they'll get there. I really wish they made low- and high-end versions of these radios - that way people had a choice between low-cost and high-quality.
That's a shame, as there is so much potential. I have a Hizpo PK5 in my (JBL-equipped) Sequoia, and it's completely noise-free. But this Dasaita for the Highlander is just very loud. It seems like it's a shielding issue. As stated previously, if I keep the head unit out with all the cables extended, the sound stops. I'm halfway tempted to buy an SMA wifi antenna with a cable long enough to get the RF signal away from the wires. The sound is exclusive to the left channel (both front and rear).
@TheDiB, missed your prior question. It's a JBL-equipped vehicle.
Yeah, your particular noise is REALLY bad (mine is more of something that you only hear if the music is muted or during really quiet parts of the music - and only in certain cases (but it still bothers me knowing that it's there).
Being that you can stop the noise by pulling the radio out, you may be able to figure out what is causing it. Maybe try disconnecting the AM/FM antenna to see if that has anytihng to do with it - I've read some cases where hte antenna was causing interference. Or just re-routing some of the wiring - or something along those lines.
In my case, the noises are present no matter what - but only if I use the RCA line-level outputs and an extrnal amp. If I use the stock built-in amp, there is no noise whatsoever. So mine seems to be related to the RCA line-level output hardware (shielding related, I'm guessing).
I would experiment some more if you are happy with the radio and sound-quality otherwise.
I'm hoping I hear something helpful back from Dasaita in the coming days. On this particular unit, the wifi antenna comes out about 1/2" above the main ISO plug for the radio. I suppose I could relocate the antenna by running the existing bulkhead SMA fitting through a screw hole elsewhere on the case to provide more distance. I'm not giving up yet The other issue is that it's the wife's car, so my access to it is limited.
I'm not using line-level outputs. The four pairs for the speaker output comes out of that ISO plug, and goes straight to the Toyota harness. Fader control (as well as a bunch of other controls/data) goes through the can bus adapter. But ultimately, those four speaker pair end up at the factory JBL amplifier.
Aside from the noise, the audio quality is equivalent to the stock radio. But, I'm not an audiophile, and I have the opposite of OCD...
So your stock JBL amp actually accepts speaker-level inputs? Usually, amps take line-level inputs. With the Eonon MTCE-WWW units for GM's, if your car has a stock Bose amp, there is a special "Bose adpater" that connects to the same port where you would connect the line-level RCA jacks for aftermarket amps, which is line-level - but instead of having RCA jacks at the other end, it just connects into the main wiring harness, so I guess it sends line-level signals through the speaker wires, to the Bose amp - and then the Bose amp amplifies them (that is just a guess though, based on the fact that the audio is coming from the same port that is used for an external aftermarket amp, which is line-level).
So the wiring harness you use for yours is exactly the same regardless of whether the car has a stock amplifier or not? Or maybe it's not an option on your car and they ALL come with JBL amps? Just trying to understand your setup a little better. Do you have a link to the unit you purcahsed?
jtrosky said:
So your stock JBL amp actually accepts speaker-level inputs? Usually, amps take line-level inputs. With the Eonon MTCE-WWW units for GM's, if your car has a stock Bose amp, there is a special "Bose adpater" that connects to the same port where you would connect the line-level RCA jacks for aftermarket amps, which is line-level - but instead of having RCA jacks at the other end, it just connects into the main wiring harness, so I guess it sends line-level signals through the speaker wires, to the Bose amp - and then the Bose amp amplifies them (that is just a guess though, based on the fact that the audio is coming from the same port that is used for an external aftermarket amp, which is line-level).
So the wiring harness you use for yours is exactly the same regardless of whether the car has a stock amplifier or not? Or maybe it's not an option on your car and they ALL come with JBL amps? Just trying to understand your setup a little better. Do you have a link to the unit you purcahsed?
Click to expand...
Click to collapse
It must, because I'm not using any coax/low-level outputs. In fact, I haven't hooked up most of the pigtail connectors. The ISO harness has about 5 or 6 connectors that are used, and about as many that aren't (presumably for the non-JBL vehicles). I think the Toyota JBL set up is much like the Bose you described. In a previous Tundra, I had to buy an adapter that would convert the two-pair per speaker wires to RCA plugs which I could then use to connect my aftermarket radio (to use the low level outputs). That converter (made by Metra or Scoche, IIRC) also somehow tied into the canbus to power the amp and control the fader.
Ultimately with this PX5, I'm using the purple/green/gray/white speaker level outputs to go directly to the factory harness. No adapter in between. I can only assume the JBL amp is designed to accept this somehow. Both my Sequoia and now this Highlander are set up the same way.
Well, I am happy to report that I was able to resolve the noise by replacing the Dasaita wifi antenna with a full-sized SMA-equipped antenna from an old Asus router. The antenna was a female SMA, so I had to slip a small copper conductor into it so it would interface with the female SMA bulkhead on the radio - but once I did that, ALL the noise disappeared! So either something is wrong with the antenna they provided, or it's simply dumping too much RF right on top of the ISO connector with all the speaker outputs. Whew!
Very cool! Glad to hear that you got it resolved. So is the antenna now further away from the ISO connector - or is it just becuase it's a different antenna? You may to get an adapter or an antenna with the right connecter for long-term use (instead of using the wrong gender anteanna with a piece of copper wire installed).
Regardless, glad to hear that you figure it out! I wish my noise-related issues were so easy to solve.
Although, I did some brief testing this morning and it seems that using the speaker-level outputs is better than using the line-level outputs on mine (for connecting external amp). The noises are still there, but they aren't as loud when using speaker-level outputs for my external amp (usually, it's the other way around with higher-quality head-units).
These units are so close to being really good - it's a shame they have these noise-relasted issues...
jtrosky said:
Very cool! Glad to hear that you got it resolved. So is the antenna now further away from the ISO connector - or is it just becuase it's a different antenna? You may to get an adapter or an antenna with the right connecter for long-term use (instead of using the wrong gender anteanna with a piece of copper wire installed).
Regardless, glad to hear that you figure it out! I wish my noise-related issues were so easy to solve.
Although, I did some brief testing this morning and it seems that using the speaker-level outputs is better than using the line-level outputs on mine (for connecting external amp). The noises are still there, but they aren't as loud when using speaker-level outputs for my external amp (usually, it's the other way around with higher-quality head-units).
These units are so close to being really good - it's a shame they have these noise-relasted issues...
Click to expand...
Click to collapse
I didn't move the bulkhead SMA fitting. I would have had to break the factory seal, and I didn't want to jeopardize warranty just yet. The antenna I added is about 4x longer than the stubby they provided, so I suppose it is spreading the RF over a larger area. It has a hinge on it and if I aim it straight back the noise is still present. Bending it 90° away from the harness makes it totally silent - and there is no depreciation in the signal strength.
I have ordered a gender changer and a 3" SMA extension cable from Amazon, but I probably won't install it unless the problem returns. I figure why rock the boat.
Is the noise you're experiencing related to data transmission? Does it stop if you disable the wifi? I'm wondering if wrapping the first few inches of the wiring bundle with copper tape wouldn't provide shielding against induced RF noise.
Ah - I see. Interesting - so just a different antenna resolved your issue. Like you said, I guess it's spreading out the signal enough to avoid causing the interference. I'm sure someone else will find that info very useful in the future!
My noise issues are not realted to wifi. I have interference noises in the following situations:
1. If car is not running and radio LED backlighting is on (cuases a hum through the speakers). Mainly only noticeable when no music is playing (between songs, for example) or when there are very quiet parts of the music.
2. When using my headrest monitors.
3. Anytime the system accesses USB devices. The interference is pretty noticeable when reading/writing USB thumb drives - especially if they have LEDs on them.
4. If I my Eonon USB dashcam is active, it makes a strange intference noise from the speakers. Again, really only noticeable when no music is playing, but...
None of these are huge issues in of themselves, but at the same time, it just bothers me knowing that the interference exists. I've also noticed that the overall sound quality just isn't as good as my previous WinCE-based head-units - (much more expensive units - they have 4v preouts, higher-quality DAC's, etc) - even when using an external amplifier. Never had interference noises with them, so the Android unit is really a downgrade in terms of sound-quality, which is more important to me than having Android, I guess. I was hoping that there woulnd't be much difference in sound quality when using an external amp, but there still is...
At first, I thought the Android head-unit was awesome while testng "on the bench" - until I connected it in-car and used it for a few days, then I started noticing all of the "cons" (warning chimes and turn-signal sounds are horrible, button backlighting doesn't dim with the rest of the interior lights when dimmed, screen isn't as nice or as bright as previous units, super-reflecitive screen, the noise issues mentioned above, no true dual-zone for my headrest monitors, no XM tuner, having to jump through all kind of hoops just to get music to continue playing where it left off when restarting the car, etc). When I add up all of these "cons", I'm just not sure the Android unit is worth it for me. I'll probably be going back to my WinCE head-unit very soon (Dynavin N7 or Rosen GM1010/1210). The WinCE units are not as flexible as the Android units, but the sound quality is more important to me.
I'd *gladly* pay more for a higher-quality Android head-unit, but right now, they just don't seem to exist - which is unfortunate...
jtrosky said:
Ah - I see. Interesting - so just a different antenna resolved your issue. Like you said, I guess it's spreading out the signal enough to avoid causing the interference. I'm sure someone else will find that info very useful in the future!
My noise issues are not realted to wifi. I have interference noises in the following situations:
1. If car is not running and radio LED backlighting is on (cuases a hum through the speakers). Mainly only noticeable when no music is playing (between songs, for example) or when there are very quiet parts of the music.
2. When using my headrest monitors.
3. Anytime the system accesses USB devices. The interference is pretty noticeable when reading/writing USB thumb drives - especially if they have LEDs on them.
4. If I my Eonon USB dashcam is active, it makes a strange intference noise from the speakers. Again, really only noticeable when no music is playing, but...
None of these are huge issues in of themselves, but at the same time, it just bothers me knowing that the interference exists. I've also noticed that the overall sound quality just isn't as good as my previous WinCE-based head-units - (much more expensive units - they have 4v preouts, higher-quality DAC's, etc) - even when using an external amplifier. Never had interference noises with them, so the Android unit is really a downgrade in terms of sound-quality, which is more important to me than having Android, I guess. I was hoping that there woulnd't be much difference in sound quality when using an external amp, but there still is...
At first, I thought the Android head-unit was awesome while testng "on the bench" - until I connected it in-car and used it for a few days, then I started noticing all of the "cons" (warning chimes and turn-signal sounds are horrible, button backlighting doesn't dim with the rest of the interior lights when dimmed, screen isn't as nice or as bright as previous units, super-reflecitive screen, the noise issues mentioned above, no true dual-zone for my headrest monitors, no XM tuner, having to jump through all kind of hoops just to get music to continue playing where it left off when restarting the car, etc). When I add up all of these "cons", I'm just not sure the Android unit is worth it for me. I'll probably be going back to my WinCE head-unit very soon (Dynavin N7 or Rosen GM1010/1210). The WinCE units are not as flexible as the Android units, but the sound quality is more important to me.
I'd *gladly* pay more for a higher-quality Android head-unit, but right now, they just don't seem to exist - which is unfortunate...
Click to expand...
Click to collapse
Hello, have you found a solution, how you fix noise ?
jtrosky said:
Ah - I see. Interesting - so just a different antenna resolved your issue. Like you said, I guess it's spreading out the signal enough to avoid causing the interference. I'm sure someone else will find that info very useful in the future!
My noise issues are not realted to wifi. I have interference noises in the following situations:
1. If car is not running and radio LED backlighting is on (cuases a hum through the speakers). Mainly only noticeable when no music is playing (between songs, for example) or when there are very quiet parts of the music.
2. When using my headrest monitors.
3. Anytime the system accesses USB devices. The interference is pretty noticeable when reading/writing USB thumb drives - especially if they have LEDs on them.
4. If I my Eonon USB dashcam is active, it makes a strange intference noise from the speakers. Again, really only noticeable when no music is playing, but...
None of these are huge issues in of themselves, but at the same time, it just bothers me knowing that the interference exists. I've also noticed that the overall sound quality just isn't as good as my previous WinCE-based head-units - (much more expensive units - they have 4v preouts, higher-quality DAC's, etc) - even when using an external amplifier. Never had interference noises with them, so the Android unit is really a downgrade in terms of sound-quality, which is more important to me than having Android, I guess. I was hoping that there woulnd't be much difference in sound quality when using an external amp, but there still is...
At first, I thought the Android head-unit was awesome while testng "on the bench" - until I connected it in-car and used it for a few days, then I started noticing all of the "cons" (warning chimes and turn-signal sounds are horrible, button backlighting doesn't dim with the rest of the interior lights when dimmed, screen isn't as nice or as bright as previous units, super-reflecitive screen, the noise issues mentioned above, no true dual-zone for my headrest monitors, no XM tuner, having to jump through all kind of hoops just to get music to continue playing where it left off when restarting the car, etc). When I add up all of these "cons", I'm just not sure the Android unit is worth it for me. I'll probably be going back to my WinCE head-unit very soon (Dynavin N7 or Rosen GM1010/1210). The WinCE units are not as flexible as the Android units, but the sound quality is more important to me.
I'd *gladly* pay more for a higher-quality Android head-unit, but right now, they just don't seem to exist - which is unfortunate...
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I also wanted to hear if you found out the problem .. since I myself have the same...

rear speakers output opposite polarity

hello. I recently changed my car's 4 speakers and I measured the polarity of them while wiring and it turned out that rear speakers output is the opposite. I confirmed it by removing the head unit and measured it with a multimeter and both rear left and right + is - fronts are ok. did they do it on purpose or it is a factory fault? I'm planning to crosswire the extension cable. did you notice something like this?
Huh? How did you measure with a multimeter?
Did you play a low frequency tone and check the voltage between the FL+ and RL+ on the AC range?
Renate said:
Huh? How did you measure with a multimeter?
Did you play a low frequency tone and check the voltage between the FL+ and RL+ on the AC range?
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I turned up the volume and checked the dc voltage between RL + RL - and RR+ RR- multimeter showed - signal. for fronts it didn't show - .
esmeraldo18 said:
I turned up the volume and checked the dc voltage between RL + RL - and RR+ RR- multimeter showed - signal. for fronts it didn't show - .
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No, that's not really a test. There might always be a little residual DC (at least as measured by a DC multimeter on a complex signal).
There are a zillion ways to check stuff, some just the electrical out of the HU, some the acoustic polarity out of the speaker.
If you put a signal into your HU you can compare the phase of the input signal vs that of a microphone sequentially in front of each speaker.
A low frequency assymetric wave can allow you to visually see which way the speaker cone is moving.
So that I wouldn't be caught out, I just checked my computer setup.
Channel ID came first, making sure that left is left.
Then I put 440 Hz tone out the computer.
Instead of locking to the PC output, I used a precision test oscillator which was certainly close enough to stay locked for a minute.
I used a microphone and compared the phase of the two signals.
I switched the microphone from in front of the two speakers alternately.
I could see that they both had the same phase.
The top trace is the microphone, the bottom the reference.
Ok, back to reality. You can check for electrical phase out of the HU by adjusting the channels evenly and connecting a speaker temporarily between FL+ and RL+. You should hear practically nothing out of the speaker.
so if I connect a speaker between FL+ and RL+ and hear nothing, does this mean polarity is correct. because I always measure the same polarity with multimeter for rears and same for fronts. I was completely sure that something is weird.
I tested this because when I turn up the volume for fronts only it has deep bass and good sound but when I start to turn up rears at balanced stage I hear no bass and when I turn up rears completely with turning down fronts I hear also deep bass. when the volume is balanced rear and front speakers cancel each other, that's why I tried to measure them, because I thought I connected speakers wrong but they were right so I removed the head unit and measured it also.
I used this video as a guide;
esmeraldo18 said:
I tested this because when I turn up the volume for fronts only it has deep bass and good sound but when I start to turn up rears at balanced stage I hear no bass and when I turn up rears completely with turning down fronts I hear also deep bass. when the volume is balanced rear and front speakers cancel each other...
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Well, it does sound like a phase problem.
If it is, then switching things anywhere will fix it.
But if you want to treat this as a research problem you can look into exactly where this problem is.
Are the front and read speakers the exact same model?
It could be the HU, the wiring, the speakers.
esmeraldo18 said:
I used this video as a guide;
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Yow! That's just wrong!
You cannot tune in your radio station and measure DC on speaker cables!
It's like a blind man measuring the size of an elephant by touching somewhere.
Your multimeter is taking a signal that changes thousands of times a second and trying to represent it with a number!
Yes, what he did with the little battery and the speaker is fine.
If you have a spare little speaker, hook it up between the FL+ and the RL+ with the F/R balance at zero.
It should get loud at all front or all rear and be quiet in the middle.
You can also check FR+ and RR+.
Then FL+ and FR+ (using normal L/R balance).
This just tells you that the HU is correct.
Renate said:
Your multimeter is taking a signal that changes thousands of times a second and trying to represent it with a number.
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I got you. All I'm saying is I'm not trying to read some values or catch something with multimeter, it does not show a static number though. But it always shows same polarity no matter what radio plays. Isn't it something worth relying? And I'm pretty sure that hu is faulty because I'm measuring directly over the pins inside sockets and at the top there is a diagram that shows which pin is positive and multimeter gives negative results for rears. Fronts are ok. These units are mass production so I'm afraid many users have phase problems they don't aware yet.
Renate said:
If you have a spare little speaker, hook it up between the FL+ and the RL+ with the F/R balance at zero.
It should get loud at all front or all rear and be quiet in the middle.
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I tested this, speaker was very quite when balanced at zero and loud all front or all rear. So what does it mean? Both cable is + and it shouldn't play anything right? But it plays when I change the balance?
esmeraldo18 said:
But it always shows same polarity no matter what radio plays.
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It's showing nothing.
Moreover, since this is switch mode (class D) amplifier the signal is actually switching at 200-400 kHz.
esmeraldo18 said:
I tested this, speaker was very quite when balanced at zero and loud all front or all rear. So does it mean the unit is ok?
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This means that the phase out of the HU is correct.
It's what I'd expect. It's pretty easy to get the design correct once.
Then they can make a million units and the phase will always be correct.
As I asked, are the rear speakers and the front speakers the exact same model, wired the same?
You can shrug your shoulders if you like and just switch the wiring so that the base is reinforced.
Renate said:
It's showing nothing.
Moreover, since this is switch mode (class D) amplifier the signal is actually switching at 200-400 kHz.
This means that the phase out of the HU is correct.
It's what I'd expect. It's pretty easy to get the design correct once.
Then they can make a million units and the phase will always be correct.
As I asked, are the rear speakers and the front speakers the exact same model, wired the same?
You can shrug your shoulders if you like and just switch the wiring so that the base is reinforced.
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No, front and rear are different, because the diameter is different but I double checked the polarity before changing them and I'm pretty sure they were ok.
Update: Renate you were right, changing polarity made things worse, I believe lack of bass is related to another problem, probably different type of speakers causing this. Fronts are 16cm jbl stage 3 627f and rears 13cm sony xs-fb131e. I understand that using multimeter is wrong, thank you.

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