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      11-11-2012, 04:06 PM   #1
mistryn's Avatar

Drives: BMW 335D
Join Date: Oct 2011
Location: Mids

iTrader: (8)

Installed amp but hissing noise comign through one speaker?

I have upgraded the following but need some help from you car audio peeople

I have the base streo which I have coded to hifi.
I have changed the front mids to Logic 7 mids and added Logic 7 tweeters
Rear speakers are still OEM

I have used a Techincs harness on the back of my HU, ran all the relavant wires down the passenger side and into the boot.

I am using a JL audio XD400.4 amp which has been mounted where the CD changer goes.

I have used 4AWG wiring - the earth cable comes off the amo and onto the chassis (wire is 15cm long)

The power cable is connected onto the main battery terminal, runs alongside the arch and acorss where my DAB/bluetooth is and then along the left arch and into the amp.

The wiring loom from the harness runs down the passenger side, up the rear passenger side pillar/cusion over the arch and into the amp (I have tried to keep the maximum distance between that and the power cable and where it does cross have kept wires at right angles)

The 4 channel amp
Channel 1 & 2 = front right and left speaker
Channel 3 & 4 = front left and right under seat subs

I have only one pair of RCA going into the amp (running it in 2 channel mode) - Red RCA = Front right speaker / Black RCA Front left speaker

From the HU harness I have connected the left rear speaker back up to the loom going back to the HU and likewise for the left right rear speaker using block connectors.

Now when I switch the ignition on I get a loudi'ish hissing/buzzing noise coming from the passenger front speaker/ The right side is fine no hissing/buzzing noise. The buzzing noise is still there when switching engine on.

I do get a bit of alternator whine coming through as I rev the car but cannot hear it while the volume is loud.

the buzzing noie gets worse as I turn the gain up so at the moment the gain for the front speakers is on 1/4 and subs just over 1/4

The buzzing noise has stumped me as I plan to re check all my wiring tommorow/RCA connections. I plan to connect a spare speaker and connect it to each channel to see if I can eliminate the noise

But anyone suggest what this buzzing noise could be and what i can do to take a look?