JL 300/4 Speaker Distortion

This is ridiculous.   Before I go on a tirade and start throwing out more advice, I have a couple of questions for you:

1)  Did you buy the amp new?

2)  Did you buy the amp from an authorized dealer?

3)  Was the amp installed by the dealer you bought it from?

4)  If the amp was not installed by the dealer you bought it from, was it installed by an individual, a retail chain, or an independent shop?

1 - USED

2- Bought it from the guy who works at the shop.  It was his own personal equipment.

3- Yes they installed it at the shop.

First of all u shouldn't have left the workshop until the sound was right. 50W RMS is plenty of power for your ears. I don't think the distortions have anything to do with the amp being too powerful for the speakers. The problems could be :

- Bad wiring of the speakers (wich can be seen on the pictures)

- Bad settings of the crossovers > Theoretically u should set the crossover point at double the Fs of the speaker. U can set it lower but with a steep slope but don't go beyond the Fs.

- Bad/No acoustical treatment of the front door > people often blame it on speakers that can't handle the power !

You sound like me back in the day when I was the consumate nice guy, always making excuses for people who screwed me over.

TCSS is right.  C'mon on, man.   He knew EXACTLY what he was doing.  Do you want to know where your engine noise most likely comes from?  It most likely comes from running a crappy set of RCAs on the same side of the car as the power wire running from the battery to the amp.  With a good set of RCAs, this probably wouldn't be an issue, but from what I can see in your pictures, you've got a crappy set of RCAs.

Everything this guy did from top to bottom is probably crap.   I'd be shocked if you have the right guage of power wire, the right fuse near your battery, and a good ground near the applifier.

Personally, I don't think you want him (or anyone else from his shop) touching your car.   Here's what I would do:

1.)  Fine a GOOD, REPUTABLE shop.

2.)  Have them bench test your amp.

3.)  If the amp is good, have them completely reinstall it for you with a brand new wiring kit.

4.)  If the amp is bad, either buy a new amp from the shop or just have the old amp removed and go back to running your speakers off deck power for awhile.

5.) Have the shop do a write up of exactly what's wrong with the amp and everything that was done incorrectly on the original install.

6.) Bring the old amp and all the wiring back to the guy that sold it to you, show him the write up from the shop,  and tell him in a calm and professional manner that you want your money back.  If he refuses, tell him that you are ready to take legal action.  If he still refuses, then leave quietly and file a claim.  If he threatens you, then tack that onto the complaint as well.

I dont' know how much you paid for the amp and the installation, but if you decide that it's not worth the aggravation and want to skip step No. 6,  that's your call, but do yourself a favor and at least take steps 1 to 5.  If you have issues with your power wire and fuse, you could end up having much bigger problems than an amp with a lame channel.