Contour Enthusiasts Group Archives Forums Modifications Audio This SUCKS! :P

Anyone ever heard of Safe & Sound in Elyria, OH? No? These are the people who installed my 4-ch amplifier and all four door speakers. This is the current setup and the problem that this setup entails...

Amplifiers;
1 4-ch Alpine MRV-F340 (click for specs)
1 2-ch Alpine MRV-T407 (old, no Alpine site, so...)

Speakers;
1 pr. Alpine SPR-136A 5.25 Component Set
1 pr. Alpine SPR-176A 6.50 Component Set
1 pr. Alpine SPR-694A 6x9" 2-way Coaxial

The 4-ch is tied to the four doors (components) and the 2-ch is tied to the 6x9s in the package tray.

When this system is going full force, you'd swear there was a subwoofer hiding somewhere in the car.

Problem is, it WON'T go full force, or at least, not for very much longer than five seconds. You crank up the bass/volume and all four doors (again, these are the components) go numb/die/stop making noises. >:(

The T407 (2ch/6x9s) keep pounding no matter WHAT I do to 'em, but crank the bass on the components/4-ch and they fall flat on their collective ***es.

Any in-depth discussion on this topic would be GREATLY appreciated as I've heard numerous suggestions as to what the problem could be and I've gotten nowhere so far trying to either fix it myself or explain it all to Safe & Sound / Rolling Sounds (they go by two names, imagine that.)

Thanks everyone,
.RMk..

I should mention what solutuions have already been attempted by my local so-called professionals.

1. 5.25 comp set "out of phase", assumed to be "shorting" amp.

2. 4-ch amp said to be getting "too hot to touch" and "shorting" because of it. I cranked the bass/volume to the point where it cuts out and it's not hot at all. It's not even warm. All I've accomplished is that the guy at S&S is either an idiot, lazy, or (worst of all) a liar.

I've also personally tried five thousand different settings with the amps and the only way to get the volume up to max is to lower the gains, increase the crossover frequencies and basically eliminate all bass and attempt to live with a tin-can effect. No thanks. This is ALPINE we're talking about here, there shouldn't be any problems. The 2-ch that was hooked up by Diamond (a different installation shop that recently closed) works flawlessly. >:(

.RMk..

Sounds like the amp is going into thermal shutdown to me. Whenever there is any high current draw the internal thermistor will shut it down. It gets hot inside where the transistors are mounted to the heatsinks which is where the sensor is much sooner than the outside of the amp will.
This means it can still shut down and feel cool/warm to the touch. Generall this is due to a short, but it can happen when the impedance of the woofers is not matched to the amp. Too low impedance will draw lots of current rather quickly when low-frequencies are present and essentially the amp sees a short.
Look at the amps and verify the operational nominal impedance: i.e. 2 ohms bridged or 4 ohms stereo
whatever it is.
Then verify the nominal impedance of the speakers, 4 ohm or 8 ohm or whatever.
Then add up all the draw on the amp that is shutting down and see if its within specs. It might be a bad amp or a bad speaker coil. Check each speaker coils resistance with the meter. It should not be too far away from the listed impedance. 4 ohm speakers are any where from 2.6 ohms to 4.5 ohms though usually less than 4. In general the resistance of the speaker is generally less than the rated impedance by around 20%. Anyway as long as it isn't close to 1 ohm or something like that unless they are special woofers.

OOH! I almost forgot. Bad connections to the amps(high resistance) will not allow enough current under high draw to supply power and the amps can cut out. Turning down the volume allows the amps to operate again.
Low Battery of course, and low charging system voltage can also cause it.
Check battery voltage with every thing off in the car using a digital voltmeter. Then check voltage at the amp using the same ground point that the amp has. If it differs significantly (lower than the battery) you have a problem.
While the engine is running but everything else off, check the battery voltage at the terminals again with the meter. You should see a minimum of 13.1 volts, as much as 14.5 depending on the state of the battery's charge.
With everything on, headlights on high, ac on with fan on full blast, stereo as loud as it will go and still play, you should see at least 13.1-13.5 volts. Otherwise look at the alternator as well.

Hope this helps, check it all step by step because there is a lot of information here.