07heat

I need a little help!

I just installed a new HU (JVC KW-NT3HDT) on my 2007 mustang. I love it and everything works/sounds great except for the shaker 500 door subs. I used the PAC C2R-FRD1 wire harness and I expected everything to wire up and work correctly from all the reviews i've read regarding that harness. I did the radio shack Diode install also.

Well now i have a horrible whine/hum in the Shaker 500 door subs only. I have two 12 in subs/amp in the trunk and those sound fine.

The Pac harness has 2 sub RCA cables however ONLY the GREEN one is the input to the door subs. My JVC headunit has a mono sub output. Now when i connect the Green Pac sub RCA to the headunit i have NO WHINE/HUM. But inorder for my door subs and trunk subs to get bass i had to buy a cheap Y RCA adapter.

Here's my dilemma:
When i connect Green Pac RCA sub cable to the Y adapter this is when i get the whine/hum in door subs only.
If i connect directly to headunit no whine.

WHAT DO I DO? I'm thinking of a RCA Ground Loop Isolator from the Y RCA adapter to the shaker 500 input and trunk input. Would that work? Any help is appreciate. Thanks

wayne613

Uhm..


According to the instruction manual here for your unit(Page 102), it has standard pre-amp RCA outs, can you not just run the 2 front ones to the front factory sub RCA's and the rear left and right to the after-market sub/amp you have? Or if everything is otay so long as the factory ones(in this case "one") aren't hooked up, then just use the front RCA's to the factory ones?

07heat

So are you saying to not even use the JVC sub RCA out and only use the Front/Rear R/L RCA outs?

Also on the pac unit the Purple Sub RCA input wire does nothing. Only the Green one is inputting sound to Both Front factory subs. I've tested this and also googled it and i've seen the same results (http://www.kenwoodforums.com/viewtopic.php?f=4&t=269).

Won't using the Front/Rear RCA output jacks from the JVC unit cause High frequencies in my subwoofers? And then i wouldn't have subwoofer control from my HU?

Yesterday i went and bought a Ground Loop Isolator from radio shack and installed it. I have the JVC HU Subwoofer output jack connected to a Y RCA adapter then into the Ground Loop Isolator which has 2 RCA jacks; one RCA into trunk subwoofers; one into door subs. The Whine/hum is gone however it seemed to strip away alot of bass. I've adjusted my Gains/Boost etc and it sounds munch better.

I'm just still a little confused on how to get my trunk subs and my door subs to work without the ground loop isolator. Any more input is appreciate. Thanks!!!!

AudioNutz

Where is each of the followin grounded:
1. Head unit.
2. PAC device.
3. Amplifier.

If there is more than one answer, there's your problem.
If these devices don't share the EXACT same ground, you've got a classic problem, the ground loop.

07heat

HU/pac is grounded through the wire harness connection.

I connected headunit ground to pac ground wire; then plugged into car wire harness. I have no idea where the Shaker 500 sub amps are grounded. I really don't want to mess with those amps cause i'm unfamiliar with them.

wayne613

I could be wrong on that count. I was under the impression there were 2 single channel amps, not just 1 powering the front subs. I'll have to go through a schematic or service manual sometime, as that's gunna bug me.
But yes, I was wrong, top and bottom (relative) on the 8pin harness seems to split the shaker 500 and 1000 sub connections as described here.

As audionutz states I'd check the ground points. I would also however just try the standard pre-outs. Just because there's a mono-sub out doesn't necessarily mean they've been bandpass filtered. You have 0 to loose, and it costs 2mins of time.

AudioNutz

Classic example of a ground loop.

Run a 10ga cable from the head unit to wherever the amplifiers are grounded, and ground it there. Then use that cable as the head unit ground, as well as the PAC device. No need to mess with the amplifiers, just ground to their ground point.

Just do this without running the cable neatly, to confirm that it solves the problem before you run the cable neatly behind all of your panels and other junk. Then when you prove that this indeed does solve it, you can run it neatly.

AudioNutz

Oh, I almost forgot.

DO NOT ground the head unit and the PAC device to ANY other ground in the dash.

07heat

I'll try all of the above.


But any idea why when i plug ONLY the RCA from PAC into HU there is NO whine/hum noise and shaker 500 subs work fine.

But when I connect to the Y rca adapter that is when there is noise.

AudioNutz

Because they are grounded together, no ground loop potential.