So i'm posting a question about a Mustang...

Sorry about doing this but Mustang forums SUCK!

My girlfriend has a 2004 GT convertable with the Mach 460 sound system which consists of 2 front door tweeters, 2 front door mids, and 2 rear deck mids. One of the front door mids was obviously blown so i replaced both front door speakers with cheap(ish) Sony speakers. They're rated at 35 watts RMS and 190 peak and have 4 ohm impedenced.

The system has an amp for the rear mids and a seperate amp for the front mids.

Now since i replaced the speakers the front mids are fading in and out under heavy bass and occassionally make a cracking or popping noise.

Here's my thoughts on the problem and any additional input is appreciated:
1. My wiring is just backwards or loose or something else is causing an issue with the wiring (ie the window is hitting it and causing it to come loose).
2. The amp for the front speaker is fried.
3. The resistance on the Sony speakers isn't the same as the factory ones and causing the amp to become unstable

Any thoughts? Her car isn't near me to check any of this stuff myself otherwise i would so i wanna have some good ideas about what to do next time i see her.
4.

 

Option 3 most likely.

Usually when repairing/replacing the MACH system, you either need to replace the entire thing with something aftermarket or purchase OEM parts.

 

Yeah i was worried about that. One of my buddies is a ford mechanic and he just told me the same thing cuz the factory speakers are either 6 or 8 ohm

 

Yup. I had a 01 mustang with the same MACH system and when i was looking into changing out 1 speaker because it was blown, Everybody told me i would have to either get some sort of an adapter/harness or change out the entire system. Their suggestion was to just change out the system.

 

Yeah i've figured out the OEM speakers were 6 ohm and replacing them with 4 ohm puts more of a load on the amp somehow and makes it unstable.

It's my gf's car and she doesn't want to put much money in to it so i'm just gonna get some OEM speakers again and hope i didn't damage the amp otherwise i'll be replacing that too.

Thanks for your input guys!! I got more of a useful response on here then i did on some mustang forums. Just another reason tacomaworld is the best forum EVER!