2G Audio/sound gurus come on in

[crimsondragon]

Currently have an annoying issue with my audio that I can't figure out. I run the bare minimum and usually as long as it sounds decent I'll roll with it. However, the sound keeps cutting out. I'm running a Kenwood KDC-X492. I've eliminated the front door speakers and the factory amp so no tweeters either. The only thing this head is driving is the stock Infinity rear speakers. I've checked the rear speaker wiring, and the wiring behind the deck. I only had the head go into Protect mode once while driving. The rest of the times it just cuts in and out randomly. I've had only the left and the right play individually to see if it's a single speaker issue and they both still cut out. One of my coworkers who dabbles in sound told me it might be the head unit not driving the speakers correctly and told me to put the stock amp back in, so I did. I used a MITAH adapter and had the blue wire hook up to the P. Cont. behind the deck. As soon as I turn the system on, I get 2 pops in the back and the head goes into Protect mode. This actually seems familiar and may be why I actually took the stock amp out in the first place.

Anyway, thoughts and opinions? So far I got a few theories. Either the Kenwood has an internal short, or the unit itself is overdriving the speakers. From what I read they're 2 ohms. The amp sending the head to Protect makes me believe that there's too much power but I have no idea. Maybe the amp is dead too? I don't suppose missing two front speakers will help either. Or maybe the rear speakers are both dying? Can a head unit send too much power to 2 speakers because there are no other speakers hooked up? Can I eliminate the overpower by disconnecting the speakers from the head and just going thru the stock amp?

 

[DJ Raydiate]

I would start by checking the ground on the HU. Also how bad off are the 20year old speakers? I know that when I did my system, all 4 stock speakers were dry rotted and no rubber/foam around the edges. They were literally floating cones. If you have another set of speakers, I would check the HU out by taking it out of the car and hooking it up to a battery. If it still goes into protect mode, then you know that something is wrong with the HU. If it doesn't, triple check the wiring. Make sure that there are no cracks/brakes in the wiring to cause a short.

I hope this helps a little.

 

[crimsondragon]

So I checked the ground to the HU and it checks out. My speakers are still decent. They sound really good when they do play. I disconnected the speaker wires completely from the head so now it only drives the sound through the amp instead and it works great. I'm guessing the internal amp of the head is dead or dying. I still don't think this is fully the solution however. In fact, even if the internal amp is dying, I want to make use of it. Since the head goes into protect mode when it sees the signal from the amp, I'm wondering if I wire in some diodes, would I be able to still boost the sound even further.

I still think it's odd Mitsu wired the sound system this way. From what I read, conventional way to wire in an amp is in series with the head. I can't see the reasoning for it and it would probably fry most head units. I bet the stock head had internal diodes.