marine install, engine (everything)noise

  • I have 1998 Mariah bowrider, 20 footer. When I bought this boat, it had a pretty decent JVC head unit in it. I began to build a system by adding a Kenwood Marine amp + 10" sub combo from Crutchfield. I installed these components plus 4 5 1/4 Polk DB speakers from Crutchfield. I noticed that the sub & amp would cut out at @ 1/4 volume. So...I ncreased the size of the power lead and  purchased a JBL Marine amp (4 channel 320 watt) just for my 5 1/4's. Had this installed by a "professional" installer, and the first thing I noticed was a loud pop when the power was turned on, then you could actually hear the CD player running through the speakers. Then the first time on the water, the engine noise was so loud it drowned out the music, and all other components, even the depth finder, turning on the lights, operating the hatch lift, EVERYTHING, interfered with the sound. I have purchased the PAC SNI-1 RCA Ground Loop Noise Isolator (2 sets). My installer is going to add these to the system and install a heavy ground wire to the battery from the amp. I will also be adding a pair of Polk DB 6 1/2's midship in the system and moving the 5 1/4's from midship to the front of the boat, leaving a pair of 5 1/4's at he rear, 6 1/2's midship and the other 5 1/4's at the front with the JVC head unit and the kenwood 10" sub and mono amp under the rear seat. So my question is; Do I need to do more to reduce engine (everything) noise and,... how can I power all 6 speakers from a 4 channel amp??? Please Help!!
  • The heavy ground wire from the battery to the amp should have been done first!!!

    The Ground Loop Isolators should help.

    The turn-on pop usually means the amp remote wire is not correctly connected to the head unit, or if it is, you might need to add a time-delay relay.

    You might need a different noise filter for the engine noise, but having a decent ground connection should help.

    You can probably run a pair of speakers in parallel off one channel of the JBL amp (so 2 speakers on CH 1, 2 speakers on CH 2, 1 speaker on CH 3, and 1 speaker on CH 4).

    Hope This Helps!!!

    2002 Ford Focus JVC KD-A815 Sony CDX-GT410u Sony XT-100HD HD Tuner Stock speakers, no amp, no subs