Car Audio help

[BassBomb]

Hello,

I've been having on and off car audio issues for years with my car, finally got around to ripping it all apart to diagnose

I have the following:
Alpine CDA-9886 (deck)
Alpine PDX5M (amp)
Infinity 60.9cs (6.5" fronts)
Infinity 692.9i (6x9" rears)
Infinity Kappa 124.7w (12" sub)

Symptoms I was trying to correct:
1. Intermittent subwoofer performance/activation. Sometimes it would be working fine (mostly worked well in winter) other times it was barely there (it would pump/push air but not make sound). Occasionally if you cranked the system or fiddled with controls it would come alive, but then die out again if you turned the volume down. SUSPECT: Subwoofer or Deck

2. Insane speaker sounds coming from front right. It would make violent sounds like it was going full extension, irregular and not predictable. I swapped RCA to rear and the same issue traveled to the rear. Consequence I used the rears only and disconnected fronts. Even if I sent the rear RCA to the front, the same front right speaker would act up. SUSPECT: Deck

Findings so far:
1. Pulled speakers, two rears have rips in the foam due to the stock speaker grill crushing them
2. Front right speaker had rip, probably due to its crazy endeavors
3. Corrosion noted on both front right and left speakers, my MDF spacer was turned to mush due to water, some rust on the speaker terminal too
4. Loose wiring or damaged wiring on 1 rear and 1 front speaker
5. Impedance check on all speakers reads 2.8 ohm, all should read near 2.0 ohm, I am guessing my Amazon multi meter is no good
6. Hooked up two front speakers in series to home audio receiver (set to 4-6ohm) and sound played without issue, noted the intermittent wiring if I moved around. Speakers sounded muddy but otherwise OK. It was played by full range so that might explain the muddiness? Did not sound blown
7. Did same as step 6 for rear speakers, barely got play through. Only one speaker really playing, shook it around and second speaker started to activate but was choppy. Intermittent wiring issue if moving around, suspect one of them is blown. <-- Confirmed!! Wire was disconnected from voice coil on one rear speaker
8. The main speakers are rated at 2 ohm and my amp is designed for 4 ohm, this could explain why they were acting up. I thought when I selected this amp it was designed for dual ohm, but that was only true for the subwoofer. Maybe the speakers were sapping power preventing the sub from activating.
9. Did continuity check on all RCA's no issues there

Next Steps:
1. Get better multimeter with smaller range for measuring the true impedance
2. Get DC power supply to test the amp at home
3. Build little clip to test output voltage of RCA pre-outs from deck

Any suggestions?

Thanks

 

[NutBucket]

First, a normal multimeter won't measure speaker impedance correctly. It's a highly inductive load so you need an impedance meter. Not worth it for what you're doing.

To me the problem (aside from wiring) is you may have damaged the amp by having it drive those speakers. Is the amp 2 ohm rated? Some are but many are not. I'd check that first.

 

[BassBomb]

Amp is not designed for 2 ohm on the speakers its 75w RMS x 4ohm. When I picked them amp years ago I thought it could also do 75w RMS x 2 ohm, but the duality was only for the mono channel in fact

Also, what I read online for this brand of speakers too is they're actually 3 ohm with some marketing BS to make it 4ohm after wiring lol

 

[Riverhound777]

All speaker issues i've had were due to wiring. Loose connections, bad contact, bad ground. Ground needs to be on bare metal, not paint. I recommend soldering if possible. That's how I had to fix an issue with my old deck. I had wire nuts connecting the speakers to the deck, but after pushing the deck back in it would pull out of the nut. Had to solder, then cover.

I haven't touched the stereo in my new car sadly, it's just such a headache.

 

[NutBucket]

Also, what I read online for this brand of speakers too is they're actually 3 ohm with some marketing BS to make it 4ohm after wiring lol

There is no speaker on earth that will measure nominal impedance with a simple multimeter. Speaker wire doesn't add measureable (with a multimeter) impedance either.

 

[BassBomb]

I understand what you are saying, I read that also. There is lots of conflicting information which shows people using it to get a basis of the impedance by roughly measuring the resistance at rest and upright.

I want to bench test my amp before going forward, to rule out speakers or amp. Hoping amp is good and speakers are the only thing needing changing. All connections will be verified and checked. My wiring up to front speakers could be suspect or the wiring behind the deck. I didn't notice ever any drop outs with respect to the deck itself (like power dropping out or steering wheel buttons stopping)

Thanks all, agreed it is a headache

 

[MongGrel]

People still worry about car audio these days ?

Most cars have more than enough options from the factory for these days. I thought that went out of date long ago, my old Mazda 3 even has a nice sound system.

Unless it is a hobbyist type thing got me, driving around with a sound system that will basically fry your ears so bad you can't even hear the music half the time went out in the 70's/early 80's.

 

[NutBucket]

Meh, still haven't heard a good system in a sub $40k car.

 

[BassBomb]

Even though my car is 2007 it had a measly audio system, something I wanted back in 2009 when I built it the first time (2007 Honda Accord)

Any modern car I wouldn't bother