Bad audio after accidental full volume blast

You blew your speakers. You are going to have to replace them to fix it. Speakers are actually quite nicer now than the old ones.

 

Hmm... I used to be in the car stereo installation biz in my younger years and that's a new one to me. Usually your symptoms can be explained by one of the speakers blowing out, but never heard of all of them blowing at once? I guess that's possible?

The basic concept is the smaller in power & quality your amplifiers the more likely you can damage your speakers. And while you can have a huge amplifier and blow out your speakers from too much power that's much more rare. Kinda like how a healthy 12v battery runs almost forever in a Prius, but soon as it's charge goes down all kinds of anomalous error codes can get thrown.

But in general, it would make sense that your problem exists prior to amplification, like somewhere in the pre-amp circuit, but that doesn't make sense because it's not where things go bad when the volume is turned up too loud.

To completely discount that all speakers didn't blow at the same time, pick whichever speaker is easiest to remove and plug in a different speaker, most any kind of speaker, to confirm the noise is still there.

If it is still there, the next step would be to pull out the deck and tap into pre-amp outputs with headphones to see if the problem can still be heard. If that's not where the problem is, then the problem is in the amplifier. If it is where the problem is, you'll need to replace the car stereo or have it taken apart and repaired. Of course, I've never looked at my '07 stereo, so it's possible that the amp and stereo system are all inside the same box, but most likely the box will have pre-amp outputs on the back for upgrades. They almost always do. Usually there's a wiring diagram on the deck, but again I've never seen my car's deck, so not sure.

If I had to guess... I'd think that is was time to start shopping for a new stereo for your car. But try above steps to be sure....

 

Most OEM stereo components are well matched and incredibly difficult to damage at full volume... But certain types of music, especially really solid sound wave synth music like dub step, or anything with sub-harmonic effects can blow speakers out regardless of design. What kind of music was on when the damage occurred?

 

I would agree normally but the speakers are 11 years old. That’s a long time for the foam surrounds to rot

 

Yes, but it's also likely that the deck and the amplifier are inside the same box... Of course, if it is only the amplifier, you can use the pre-amp outputs to bypass the bad amp and put a new amp under the seat or somewhere else. Probably a good idea to upgrade your speakers with ones that are higher quality better match to the new amp too. Also running new wires was always a standard back in my car stereo days, because OEM wiring harnesses are designed to keep costs to a minimum, not provide high quality