lgd

I had future shop put in a mtx amp and ifinity speakers for the rear, the guy warned me there could be engine noise, but i got it installed anyways, well there is engine noise and when i turned the car off there is a loud thump... anybody have any advice for me

Young Audi Jedi

...they didn't do a good job on the install. Had you not shared the thump, I would have predicted it.

lgd

Why does it make a thump?
Oh and another thing I thought since you can only hear the engine noise at low levels that i could just turn off the stereo when not in use but i tried and the amp stays on... Its really pissing me off every time I hit the gas theres a whining sound.....

formerly dennisA4

And did you only upgrade the rear speakers? Just curious.

518 Jersey03_T

you should get a switch mounted up front to turn the amp on and off, most my friends do that.

Skibum the Original

Does it thump when you turn the stereo off or just the car off? try shuttin the stereo before you shut the car off.

TTnavA

hmm..i had an amp installed and a woofer, no problems at all or whining noise when driving...need crossover maybe...

ErikNYC

tell this shop to get a clue.

This reason for the engine noise is a ground diffrence between the amp and the head-unit. Tell them to reground the amp better and make sure the RCA lines are not picking up noise from the amp wire. If worse comes to worse they need to ground the head unit at the same place as the amp. Although I dont think its as easy with the Audi head-unit (not like an aftermarket head-unit).

The thump is probably due to the amps design picking up turn on/off noise from the head unit. Some better amps have a "mute/delay" circuit for this.

Crs-KWaf

the whining is alternator whine.. it happens when the amp isnt grounded properly.. also, they should have ran the remote lead (the wire to turn on/off) and hooked it onto your factory stereo power wire.. thats a ****ty install.. I would ask them to fix it or goto another shop..

Young Audi Jedi

You're right on Erik. lgd, he's right.