[Amp came alive again] Subwoofers, bass not working

[jvictormp]

Hi guys.

My audio system is not reproducing bass anymore.

I disassembled it to check the wires and they look fine.





I measured the resistance and read 3.20 ohms. Both sides give the same reading. The cable for the multimeter has 0.5 ohm resistance, I don't know if that means that the subs are having 2.70 ohms or not. They are Logic7, so I guess it should 4 ohms or more, right? Anyway, wouldn't that be a good measure of condutivity and should be working fine?



The driver side actually works for half a second each 30 seconds or more.

The voltimeter reads 0.1V in the connector when disconnected from the sub, and 0.0V when connected.

Checked if amplifier got any water, but it's full dry.

I've read in the forum that most of time when that problem happens the subs are gone, and I actually have plans of upgrading to Bavsound, but this is not a good moment to do that move because I have some other priorities.

Maybe, if I drink something between 2 and 20 beers these days, I can make the move, but I'm really afraid the problem could be something else.

I did make a coding recently, and can't remember if I listened music since then, but the only thing I did was removing cornering lights ($524) and EDC ($223) because of a coilover install. No problems related, I don't think that could be related also.

Let me know what your thoughts are. TIA.

[RocketyMan]

Have you actually tried testing the subs functionally? Testing resistance is a good first step. Your value of 3.20 ohms makes sense for "4 ohm subs" since resistance isn't totally an accurate number for measuring sinusoidal wave forms, hence impedance would be used here.

Try taking a little 9 volt battery across the terminals and see if the speaker responds with a small load. I think you'll find that they still function. If this is the case, I would suspect your amp.

Have you tried accessing your amp connector? Try disconnecting it and determine if there is any corrosion on the connector. Sometimes pin fretting can accumulate and reseating the terminals can help with re-establishing connection.

You're on the right path.

As an FYI, the bav subs are way overpriced for what they're worth IMO.

[jvictormp]

Originally Posted by RocketyMan

Have you actually tried testing the subs functionally? Testing resistance is a good first step. Your value of 3.20 ohms makes sense for "4 ohm subs" since resistance isn't totally an accurate number for measuring sinusoidal wave forms, hence impedance would be used here.

Try taking a little 9 volt battery across the terminals and see if the speaker responds with a small load. I think you'll find that they still function. If this is the case, I would suspect your amp.

Have you tried accessing your amp connector? Try disconnecting it and determine if there is any corrosion on the connector. Sometimes pin fretting can accumulate and reseating the terminals can help with re-establishing connection.

You're on the right path.

As an FYI, the bav subs are way overpriced for what they're worth IMO.

Thanks for responding.

I'm at work offshore right now, will be home only in 3 weeks.

I didn't test the speaker itself, but I will. There's a stereo system at home that I can connect the speaker to and see if it works. Or just do the test with the 9 volt batt.

I was prone to blame the amp because of the ohmmeter reading, but after researching a little, I thought other problems could cause the speaker to stop working even with resistance reading fine, and one could have been gone much time before the other and I don't notice, and it would be very strange to have the amp losing 2 channels simultaneously.

Just can't buy new speakers before having 100% certainty. And no, I didn't access the amp yet. Just inspected for water flood with a boroscopic camera.

Anyway, would you suggest a better brand than Bavsound for that price range (or even cheaper)?

[RocketyMan]

Originally Posted by jvictormp

Thanks for responding.

I'm at work offshore right now, will be home only in 3 weeks.

I didn't test the speaker itself, but I will. There's a stereo system at home that I can connect the speaker to and see if it works. Or just do the test with the 9 volt batt.

I was prone to blame the amp because of the ohmmeter reading, but after researching a little, I thought other problems could cause the speaker to stop working even with resistance reading fine, and one could have been gone much time before the other and I don't notice, and it would be very strange to have the amp losing 2 channels simultaneously.

Just can't buy new speakers before having 100% certainty. And no, I didn't access the amp yet. Just inspected for water flood with a boroscopic camera.

Anyway, would you suggest a better brand than Bavsound for that price range (or even cheaper)?

100% agree that we want to confirm the problem before swapping in very expensive speakers.

In my experience, I like having fuller bass in the car and I have experience installing a designated sub and joining amp. I was able to do this well under $500. Bav is overpriced hype IMO.

Anyway, once you get back to shore, report back your findings and we'll then figure out the issue.

[jvictormp]

Out of nowhere, the bass is working fine.

I said I've checked for water because the day of the problem I went through a tough rain. But I didn't quite check, just looked for with a boroscope.

Anyway, would only bass suffer from water flood in the amp allocation?

I guess I'll have to wait for the next rain.

[RocketyMan]

Could very well be a connection issue, and you checking the sub-could've re-established that connection. There has also been reports that the MOSFETs get "lazy" from time to time in the AMP. To fix this, you have to play a song with volume up that has "thumping" bass to turn the FETs on.

I don't think you clarified, do you have individual audio or the HiFi one? What color are the cones on your door speakers?

[jvictormp]

Originally Posted by RocketyMan

Could very well be a connection issue, and you checking the sub-could've re-established that connection. There has also been reports that the MOSTFETs get "lazy" from time to time in the AMP. To fix this, you have to play a song with volume up that has "thumping" bass to turn the FETs on.

I don't think you clarified, do you have individual audio or the HiFi one? What color are the cones on your door speakers?

My equipment list says S677A - HIFI SYSTEM PROFESSIONAL DSP.

My car is 2008, and there's no yellow cones on door speakers.

[RocketyMan]

Originally Posted by jvictormp

My equipment list says S677A - HIFI SYSTEM PROFESSIONAL DSP.

My car is 2008, and there's no yellow cones on door speakers.

Oh nice! Thanks for reporting that.

In this case, yeah, I've heard of the HiFi amps needing to be "turned up" to activate the lazy FETs for the subs. Not much more explanation I can give other than it's typical.

[jvictormp]

Well, car's been out during an entire day rain, and now amp's out.

I don't know why the water didn't drain, but I removed the rubber "drain plug" for now.

My laziness cost me this defeat. Signs were there and I didn't pay the attention needed.

I don't know if it's really dead or repairable, but I'm thinking on upgrading to Audison Forza M8.14.

What you guys think about it?

https://www.ebay.com/itm/27725836793...BoCV68QAvD_BwE

[RocketyMan]

I would def look at where the ingress of water is coming from. Otherwise, the new amp you install would suffer the same demise. For this case, I would suspect the trunk gasket is not sealing correctly, and/or the rear tail light. The rear tail light is supposed to have a foam gasket to help seal it.

Did you notice any of the insulation wet around in that area that might point you towards where water is getting in?

You could try using some DeOxit to spray the PCB of the amp to see if you could get some functionality back.
https://caig.com/product/deoxit-d5s-6-lmh/

As for your Audison, I think is rather high priced and overall not worth it. A replacement is much more affordable.

P/N: 65129218086

https://www.ebay.com/itm/25718351952...3ABFBMgp-qi89m

[jvictormp]

Thanks the reply. Fortunately my amp came back to life after IPA cleaning.

I followed this video instructions:

And by the pictures you can see it wasn't too bad, except for one single chip.

After cleaning, I reapplied the thermal paste.

Then I connected the amp again, and man, I can't say how glad I was to hear the BMW chime!

Next move, I checked the drain plug that was supposed to let water flow to the outside. For my surprise it was a blind plug, no orifice, almost a perfect seal. I think it wasn't meant to be there, maybe some previous owner did some sh*t. Well, for now it turned out into a real drain plug, cause I drilled an orifice on it.

Drain test was fine:

Then I searched for the leakage source, throwing some water on the top of the rear windshield, and found out it was coming inside through the tailight seal.

All good to go, problem solved.

[RocketyMan]

Nice report back.

Did you find out how the water was getting in? Otherwise you might suffer the same demise again.

[spammysammich]

Drain plugs are designed to be waterproof and removed as needed to drain an area. They are not passive draining devices like a one way check valve. You NEED to fix the point of ingress. The plugs are working as intended. If you made a through hole in an area subject to water splashing, now you have created another problem. Hopefully your solution will be enough for your problem until you can properly diagnose the issue and fix it permanently

[jvictormp]

Originally Posted by RocketyMan

Nice report back.

Did you find out how the water was getting in? Otherwise you might suffer the same demise again.

It's going through the tail light seal. One of the videos shows that.

Originally Posted by spammysammich

Drain plugs are designed to be waterproof and removed as needed to drain an area. They are not passive draining devices like a one way check valve. You NEED to fix the point of ingress. The plugs are working as intended. If you made a through hole in an area subject to water splashing, now you have created another problem. Hopefully your solution will be enough for your problem until you can properly diagnose the issue and fix it permanently

Well, you've got a point, I didn't think of it that way.

I'll have to re-think of the problem because now I can't imagine having that drain plug sealed again

Even if I change the tail light seal, maybe I should remove the CD changer, etc above and reposition the amplifier a little higher.

[RocketyMan]

Originally Posted by jvictormp

It's going through the tail light seal. One of the videos shows that.




Well, you've got a point, I didn't think of it that way.

I'll have to re-think of the problem because now I can't imagine having that drain plug sealed again

Even if I change the tail light seal, maybe I should remove the CD changer, etc above and reposition the amplifier a little higher.

Okay good. I didn't catch one of your videos showing the water ingress location you found. I now just watched it. Did you try taking out the tail light to reposition the foam gasket? Perhaps it just needed to be properly tightened up?


Spammy is correct. Those plugs are really only there for emergency situations.