One Quiet Speaker - Need Help

[waterskiguy_24]

Im hopeing someone has seen this before and can give me some advice. I have one speaker thats quieter then the rest. I replaced all my speakers with aftermarket ones coming up on a year ago. Sounded great. Everything worked perfectly. I noticed recently that the front passenger speaker is all of a sudden quieter the the drivers side. Its not a balance issue. Its not a speaker issue. I pulled the two front speakers out today and swapped them side to side. The quiet side remained on the passenger side. That tells me the speakers works fine. I then pulled the stock head unit out and checked the impedance along the wire, from where it plugs into the head unit to where is plugs into the speaker. Im getting the same impedance across all 4 wires (2 positives and 2 negatives) so that tells me the wires are fine. This all leads me to believe that its a head unit issue. Anyone seen this before? Any idea what could cause this? Ideally id like to keep the stock head unit, and im hoping I dont have to replace the unit all together. Thanks.

[sas]

Any chance you have a crossovers? Had disconnected the battery?
What does it mean the same resistance? It has to be 0 Ohm.
So far you did all tests correctly. You missed to check if wires and speaker are isolated relatively to the ground. You can download HERE (http://ampguts.com/cmps_index.php?pageid=audio_downloads) the sine signal for 50 Hertz to compare a real voltage from head unit. The sound can be quiet in right channel but the sine have to be smooth, without distortions.
Also, you can check if you have a dry electrolytic capacitor inside of the head unit, the difference in voltage at high frequencies will be much smaller.
There are no sine signals for high frequencies, you can use the pink noise for 6.4kHz.
Or you can download the IASCA disk, there are tracks for stage positions filtered by low and high pass filters.

[waterskiguy_24]

stock head unit... no crossover. mono amp wired to rear speakers. rear speakers and sub work fine. The front speakers both read 4 ohms resistance because they're 4 ohm speakers. The wires from the head unit to the speakers read 0.5 ohms of resistance over their length. The battery has been disconnected a few times, like when i installed the speakers. Everything worked perfectly and sounded great all summer and through the fall. All of a sudden, last week, the one speaker dropped in volume. How do i check if the speaker is isolated from the ground? I can imagine it wouldnt be. All i did was hooked up the after market speakers to the stock wiring. Like i said. everything worker perfectly for 6 months. Dave wood wont cover the head unit under warranty because of the aftermarket speakers, so if theres no way to fix it, I have to decide whether to buy a new stock head unit, or put in my alpine unit and lose the integration with the screen above it that shows fuel economy, etc.

[McGuyver_3]

why dont you put stock speakers back in and go back for warranty? as long as the problem is happening with stock speakers installed theoretically it should be covered.

[sas]

You have a sub. If this sub is connected to the front I’d had double checked wiring and LOC.

You can measure the resistance between one of the speaker’s wires (on the removed from HU connector ) and ground (chassis). The second wire will be checked automatically because it remaining connected by speaker. The nearest ground in the cabin is the metal ring of the cig lighter. There shall be no connectivity between harness and ground.

If problem will be narrowed to the HU. As I see, the power amp (TA8263BH) for HU can be ordered for 13CAD, the repair shouldn’t be very expensive.

[waterskiguy_24]

McGuyver, I cant just put the stock speakers back in because the wiring for the sub/amp is spliced in behind the head unit. It would be obvious that its been tampered with. That thought had crossed my mind though.

Sas, the sub is definetely wired to the rear speakers because when I checked the resistance in the front wires, I was touching the ones that didnt have the amp spliced in. No LOC. The Alpine mono amp I have has a speaker level input built in.

[dj_adamix]

It sound like your IC/amp is out for one channel. you can buy a new head unit off ebay for around 40 bucks. or you can just buy this (TA8263BH) and solder it in. now im not sure if its smd or just regular solder techinque. but either way its duable. now that amp (TA8263BH) is a IC that has 4 channels in it, It could be that or it could be something else burnt thats on the path of your channel. its hard to tell without looking inside and testing all the components. im not sure how the controller is hooked up to the amp in there. if its 1 signal controlled by the controller and passed to the amp and then it gets spliced in 4 channels or if its already spliced in 4 different channels in the controller. if thats the case it could be your controller IC that its not regulating the volume on that channel.

[sas]

You can disconnect the input from amplifier, just to check. The HU’s amp is made in one chip, and theoretically there is a possibility that the leak in one channel might to cause a problem for others.
McGuyver’s idea sounds most attractively and realistically. In other hand, in my opinion, I don’t think that the absence of trip computer is a big deal. There always more then 10 liters per 100km, lol.

As for how it is connected. There is the audio processor TDA7437. Volume, balance ,etc
are changed by 8 bit digital commands. Four processor outputs are connected to the four amp inputs via chain with capacitor and 1.5-2kOhm resistor ,connected in series . Also every input has a small grounding capacitor to kill high frequency noises. It’s all.

[dj_adamix]

You can disconnect the input from amplifier, just to check. The HU’s amp is made in one chip, and theoretically there is a possibility that the leak in one channel might to cause a problem for others.
McGuyver’s idea sounds most attractively and realistically. In other hand, in my opinion, I don’t think that the absence of trip computer is a big deal. There always more then 10 liters per 100km, lol.

As for how it is connected. There is the audio processor TDA7437. Volume, balance ,etc
are changed by 8 bit digital commands. Four processor outputs are connected to the four amp inputs via chain with capacitor and 1.5-2kOhm resistor ,connected in series . Also every input has a small grounding capacitor to kill high frequency noises. It’s all.


Yeah so it might be your controller IC thats faulty and its not controlling the volume on one channel. Or it might be the amp. Either way i think it woulf be cheaper to just get a used head unit or dig one out from a scrap yard somewhere.

if you decide to fix it you might spend more on parts and more time consuming trying to de solder and solder it back in.

[McGuyver_3]

If it really is a headunit then you will have to remove those items tape them up. Dealers theory usually is if its happening stock no add ons even though the wiring has been tampered with they will do something about it. They claim oo you screwed around with the wiring......SOOOOOOO WHHHAAAAATTTTT? prove to me that the tampered wires did anything. Dealer: you had bla bla bla installed last time and took it out. YOU: ok and the problem is still happening 100% stock so fix it
of course stay in a cool mood dont get fussy


McGuyver, I cant just put the stock speakers back in because the wiring for the sub/amp is spliced in behind the head unit. It would be obvious that its been tampered with. That thought had crossed my mind though.

Sas, the sub is definetely wired to the rear speakers because when I checked the resistance in the front wires, I was touching the ones that didnt have the amp spliced in. No LOC. The Alpine mono amp I have has a speaker level input built in.