Speakers Dropping Out! - I'm Chasing My Tail Here

[cowie165]

Guys I'd love to hear your thoughts on what may cause the problem I'm having with a stereo. It's on our Mazda, not the Nissan, but SAU is where I've always found guys willing to lend a hand.

When we bought the car a year ago, RL and RR did not work. We didn't care, it is a spare car. When FR dropped out (as in, the output volume dropped to negligible, but audible) we assumed the speakers were slowly dying (its a 1993 car).

I removed FR and suddenly the rears were working again!? At the same time, FL was MUCH louder the the rears combined.

I thought the lack of FR may be causing an overvoltage to FL so I removed that one too. Now the RL is louder than RR?

Anyway, I'm stuffed to work it out. If it matters, the fronts are splits and I only removed the bass driver from the door. I was hoping someone here could shed some light on the cause before I ask someone to come out to my place. I'd rather avoid rewiring the whole car if i can help it.

Thanks guys, any assistance would be appreciated. Cheers

Mark

[Chris Rogers]

car type(model) pls and I'll attempt to help. a pic of the radio would be nice as well.

[cowie165]

Hey thanks Chris. It is a 1993 Mazda 626. I'll take a pic this morning. Its a Phillips two single DIN setup. One has CD only other has cassette and radio.

I'll come back with pics.

[RANDY]

Did the stock HU use a common ground for fronts and another for rears? Or are you simply reusing all the original wiring?

Sounds like you might be using the negative of one speaker on another speaker or something like that?

[cowie165]

Hi Randy, thanks for the post. The wiring was ambiguous so I had to test both ways (both wires had a trace colour). To be honest, I couldn't tell the difference either way. I guess I'll go back and swap them over and check again.

Now that both fronts are gone, RL is still much louder than RR and both lack the bass you'd expect from a 6x9 - they sound more lie 4's

Chris here's those pics. Thanks for taking a look.

For what it's worth, the new speakers are 45W RMS. Could I be asking too much of the headunit? I wouldn't think so, but thought it worth mentioning as it's an old car.

Cheers guys

[jasont82]

i know its probably not this but if it was you would look a bit silly. its not something simple like the balance knob from left to right is it? cant see from the picture but some stock radios have that little knob around the volume knob that balances it, or sometimes is the bass control.

[jasont82]

might have something to do with the crossover thingy for the splits too. Might be wired backward on that.

[cowie165]

Cheers Jason but yeah I've played around with the fade/balance/bass/treble. That was how I've been diagnosing the differing output. Hey there are no things that are silly, always helps to start from the start rather than assume

I haven't touched the splits, although I have removed the bass drivers from the door. The tweeters still have some poor quality noise (won't call it sound ) coming out of them.

Could that be related?

[Chris Rogers]

Hey thanks Chris. It is a 1993 Mazda 626. I'll take a pic this morning. Its a Phillips two single DIN setup. One has CD only other has cassette and radio.

I'll come back with pics.

ok if its a sedan check the rear wiring ont he speakers. if you shove a lot of stuff in the boot there is a good chance that you have knocekd the terminals off the speaker and they are shorting.

this will do a few strange things to the radio- one of which you have already described.

[Chris Rogers]

Hi Randy, thanks for the post. The wiring was ambiguous so I had to test both ways (both wires had a trace colour). To be honest, I couldn't tell the difference either way. I guess I'll go back and swap them over and check again.

Now that both fronts are gone, RL is still much louder than RR and both lack the bass you'd expect from a 6x9 - they sound more lie 4's

Chris here's those pics. Thanks for taking a look.

For what it's worth, the new speakers are 45W RMS. Could I be asking too much of the headunit? I wouldn't think so, but thought it worth mentioning as it's an old car.

Cheers guys

one thing to also look at (now that I have mroe info) is the crossover network. depending on how lound you have it most amplifiers will go into protection at 3/4 volume so that may be a thing as well.

first thing I would do would be to eliminate te crossover on the offending side and see. as for power - nope. you will kill them with too little power but that isn't your current problem.

[cowie165]

Thanks Chris. Based on your info, I suspect the FR crossover isn't working properly.

I'll take the dash out and see how the terminals look.

Cheers!

[RANDY]

Maybe for fun, use the RL (loudest) wiring from the HU, and just hold them to the wiring for each other speaker and compare? If all the speakers are just as loud, then it'd be a HU problem I'd assume.

If they still act up, then yeah.. you could have a few shorting somewhere, or a dodgy crossover.

Hmm.. still.. the whole thing screams wiring... like common ground. You have the stock speakers, right? My lady's Honda was crazy like that too.

It was almost like the commonly-grounded speakers were doubling the resistance back to the HU. (halving the ohm value) and therefore upping the HU's wattage output. I doubt this is the actual case, because 8ohm stuff is generally reserved for HiFi stuff, and cars use 4ohm and sometimes 2ohm for subs.

Anyway, definately troubleshoot it down. Unplug all from HU. Grab the loudest output pair from the HU, then test them to each speaker. Shouldn't need to power the HU off for this test.

[Chris Rogers]

randy,

if it was earlier than 85 I would agree with you. anything mazda after that wasn't common wiring.

[cowie165]

Thanks Steve, that helps too. Cheers mate. I'll have a play and let you know what I can work out.

[RANDY]

Chris: Ah yeah! Fair call. My lady's car is an '84 Honda Civic, so that makes sense!

Mark: No problems! I hope you get it sorted!