[zapata12]

Any help is greatly appreciated.
I went to car toys to get a new amp and converter installed with the 12" sub woofers I have in my trunk.. Afterwards the 8" subs in the car underneath the front seats started to play a scratching noise at certain frequencies or loud volume.
The installer told me the 8" subs were probably old soo I bought new speakers and subs and installed them but the problem is there.
I am not sure if the installer messed up the wires or tapped into the wrong wiring or if the subs in the trunk cant be played with the subs in the car.
I also had to go back after the installation because the 12" subs in the trunk started smoking.

I have a Alpine R-A75M Amplifier..
https://www.alpine.co.uk/p/Products/...lifiers/r-a75m
two 12" kicker subwoofers
https://www.kicker.com/comp-r-12-2-ohm-subwoofer
LC2i PRO - AudioControl
https://www.audiocontrol.com/car-aud...rade/lc2i-pro/
finally Bavsound ghost subs and speakers for a HI-FI system.

[ctuna]

There aren't a lot of shops that are good at doing BMW stereo.
Have you tried to get him to correct.

The Hi Fi stereo system is not very good in the first place.
Amp is weak and speakers are sub par.

A big sub just means you have a Hi Fi system with overwhelming bass.

It would have been better to get good sound out of the Hi Fi system first
then add a sub if you wanted one.

Not fond of the LCI I don't know why you would use that.
Sounds like he is tapping of the Speaker outs rather than the
Input signals to the amp .

[zapata12]

So yes I did try to get them to correct the issue but they recommended disconnecting the 8"subs underneath the seats. The reason I did not try upgrading the HI-FI system was because I already had the 12" sub woofers and I moved those over to my new BMW. Also I had a simple not great convertor prior to the LCI and they recommended upgrading it, I agreed because they are SUPPOSED to know more then me.
Also could you please let me know where I am supposed to be tapping, I am gonna get inside the trunk to take a look at the connections then I could let you know what he did and if he did it wrong I'd appreciate if you would let me know.

[ctuna]

When they tell you to disconnect the under seats it sure sign they are idiots.
Because in a system where you have 4 inch doors and going to a sub there is
no mid range.

https://www.e90post.com/forums/showthread.php?t=138949

https://www.e90post.com/forums/showthread.php?t=641323

One of the big problems with your setup is factory amp is crap.
The one that powers all the OEM built in speakers and those are not
very good either.

subwoofer threads
http://www.e90post.com/forums/showpo...2&postcount=66
http://www.e90post.com/forums/showth...t=Ultimate+Sub
http://www.e90post.com/forums/showth...ight=subwoofer

[zapata12]

Yea that is what I was thinking; they were just telling me bullshit because they do not want to fix their poor work.
I should have known when getting new speakers and subs for my car I may as well have gotten an upgrade from the factory amp to power the new things. After replacing the factory amp, do you think the problem with speakers within the car will be fixed?

[ctuna]

The factory amps in these cars will never give you decent audio.
The Logic 7 might be OK for a lot of people that are not critical
about audio but it's not anything that anybody that is serious about
music would put in .

[zapata12]

Thank for the help; I fixed what the jackass did wrong..
He spliced the negative wires from the left and right subs underneath the seats to form one wire to go into the convertor and the same thing with the positive wires. Cannot believe I paid money to these fools for a "professional job".
However I did start looking at bimmertechs' amplifier and although it is expensive it looks promising and will be the next thing I upgrade.

Also Ill attach pics from the car so you can see also.
https://drive.google.com/drive/folde...-A?usp=sharing

[ctuna]

Both Bavsound and Bimmertech use rebranded Audiotech Fisher
BMW 7 and 86dsp amp/dsp respectively . They add a tune .
The tune in the Bavsound is locked down the Bimmertech isn't .

Did the rewiring clear up your sound?
Or at least take the part out you where complaining about.

[zapata12]

Yes after I rewired and ran everything the way its supposed to be, the bad sound from the subs went away. Problem was paying other people money to do what I could apparently do better haha.
Thank you for the help and advice, clutch!