Jump to content

Welcome to TheMalibuCrew!

As a guest, you are welcome to poke around and view the majority of the content that we have to offer, but in order to post, search, contact members, and get full use out of the website you will need to Register for an Account. It's free and it's easy, so don't hesitate to join the TheMalibuCrew Family today!

Static Noise in Speakers?


Cory

Recommended Posts

We'll I just about finished my stereo installation on my boat this weekend, but am having one issue...

My system description: I have the RCE front & rear out from the HU fed into a HD600/4, which drive 8 cabin speakers. I've run an RCA cable from the front channel pre-amp out on the HD600/4 to an XD400/4 to drive the tower speakers. The XD400/4 is setup in bridge mode to drive just two tower speakers so I had to use RCA splitters to retain L-R stereo on the tower (manual recommended this configuration). I also have an XD600/1 driving the sub off of the RCA sub output on the HU. The HU is not driving any speakers anymore. I cut those wires and ran them to the HD600/4. Pictures of the installation are below (I haven't mounted the board to the side of the boat cause I'm having a static noise issue).

pic1_zpsa0cdcef9.png

pic2_zps9efda0c6.png

My Static Noise Issue: I'm getting static noise on the RCA front and rear outputs from the HU. If you increase the gain on either the cabin amp or the tower amp, the static noise gets louder or quieter accordingly. The level of this static noise stays constant when you increase/decrease the volume on the HU. I disconnected the RCA cable running to the RCA FRONT OUT on the HU and plugged it directly into my iPhone and the static on the front four speakers and the tower speakers (which are driven by these RCA outputs) disappeared and sounded amazing. So, I know the cabin amp and the tower amp can produce a clean sound without static noise.

The three amps are powered by the distribution block in the picture above (4 gauge wire to each amp and 2 gauge wire to battery). The HU is powered from the yellow and black wire that connects to the amp right next to the HU (this is how the factory drew power for the HU. I tried running those wires to the power distribution block, but it made no difference on the static noise. The yellow wire, which I think is the power wire for the HU, is described in the manual as the "MEMORY back up" wire??? The wire, which the HU manual describes as "RED IGNITION SWITCH (B+)" runs to a blue and white wire in the factory wiring harness, which I assume runs to the ignition. I'm considering cutting out that white factory connector on the backside and coupling the power wires and ignition wire directly. Could the noise be entering through the AUX IN RCA cables (I have not made any changes to these connections from what the factory did). I ordered the boat with all speakers pre-installed, stereo option 1, and the factory sub and amp (I removed the factory amp).

Why is my HU generating this static noise on the RCA outputs? It's not awful, but it is annoying enough to bother me and my wife even noticed. Any thoughts/comments would be appreciated.

Edited by Cory
Link to comment

Are all your grounds in one common ground or are they seperate, and where are you grounding to? You most likely have a ground loop. I had the same problem on my Moomba until I cleaned up the ground to one common ground and a good one at that.

Here is a good article on the problem: http://www.epanorama.net/documents/groundloop/

Link to comment

yes, all three amps are grounded to the ground distribution block on the amp board. The HU is grounded to the distribution block via the 4 gauge ground wire that grounds the tower amp. I tried running the power and ground for the HU directly to the distribution block, but it made no difference.

The "RED IGNITION SWITCH (B+) wire on the HU is the only voltage source to the HU that is not coming from the power distribution blocks on the amp board. But I assume that must come from the ignition.

Edited by Cory
Link to comment

Gotta change the ignition B+ supply over to the same distribution point as the amplifiers also.

If you want to maintain the keyed ignition function then add an interrupt relay.

David

Link to comment

I changed the ignition B+ supply over to the same distribution point, but no change--the static is still there. The static is definitely coming from the HU, since I get no static when I drive the cabin & tower amps directly from my iPod (I just pop off the RCA cable connected to the rear or front RCA out on the HU). Just to be clear, I'm not getting a hum, it white static noise that I feel is just a little too loud to be acceptable.

What gauge of wire should I be running to the HU 12 pin wiring harness? It looks to me the factory simply ran 16 gauge power wires to the 12 pin harness and I've continued to use these wires. The wires running into the HU from the 12 pin harness look pretty thin, so will beefing up the wires after the harness make any difference?

Is it possible I could have a bum HU? I'm pretty frustrated right now and almost ready to just buy the new RFX5000 HU (though I can't find it for sale online).

Gotta change the ignition B+ supply over to the same distribution point as the amplifiers also.
If you want to maintain the keyed ignition function then add an interrupt relay.

David

Edited by Cory
Link to comment

OK- Very unlikely you have a bad HU. this looks erily like a problem I had on my last setup, and I think you are doing the same thing. Miswiring the amps. Need more pics of your setup, but I am pretty sure this is whats going on...

I am looking at that first black JL XD400 amp there next to the HU, I see Y splitters off those RCAs? WHY Splitters?? not necessary---> Why 4 RCAs for only bridged 2 tower speakers?? not necessary. Also you have it in 4 channel mode for your 2 channel speakers? You should see 2 RCAs going into that amp bridged in 2 channel mode.

THAT will certainly cause noise issues, it did the exact same thing on my last NVX till i figured out it was the 2nd set of RCAs in bridged 2 channel mode was causing the issue. I guess its like double feeding the RCA inputs and causes a feedback issue. not sure exactly what its called. Easy fix.

Post of some close up terminal pics of that far XD400 powering your inboats when you get a chance.

Link to comment

The XD400/4 is wired correctly in this case and exactly per the manual. That is not the source of noise in this particular product as it is done this way 100% of the time in this application with no noise.

David

Link to comment

Cory- probably worth 30seconds to flip a few switches on the amp and RCAs to verify that's not the problem. 100% of the time.

"If you wish to send four discrete channels into the XD400/4, simply use all four inputs and set the Input Mode switch in the 4 Ch. position.

If you wish to use only two channels of input to deliver signal to all four amplifier channels, set the Input Mode switch to 2 Ch. and use only the inputs to channels 1 & 2. In this mode, Channel 3 will operate with the Channel 1 signal and Channel 4 will operate with the Channel 2 signal."

Link to comment

Below is a picture of the input to the HD600/4 and XD600/1. Tonight I will beef up the power leads supplying the HU, but I don't think I can go any thicker than 12 gauge wire and still make a reasonable connect to those tiny input wire to the HU. After this I'm all out of ideas.

I have already tried disconnecting every input in the HU (other than a single RCA into the AUX to provide a source signal) and I'm still getting static noise. Interesting note, you can turn the HU on, provide a source signal and then disconnect everything (including the remote control at the helm) and the system will continue to play on the selected input. Of course, power and an RCA source cable were still connected. I've tried disabling two of the three amps and just driving a single amp with the HU and I still get static. I disconnected the medallion mobile gateway from the unit that sends signals to the helm (thinking it may be emitting noise) and that made no difference.

photo_zps8f15e3a3.jpg

Link to comment

Is it possible I'm being too picky??? I don't know what a normal level of white noise from a HU is... I do know that my iPhone produces significantly less white static noise than this HU.

It's a notorious issue with those BB units, couple that with the low output voltage making gaining the amps higher necessary and you've got yourself some noise.

Link to comment

It's a notorious issue with those BB units, couple that with the low output voltage making gaining the amps higher necessary and you've got yourself some noise.

would a line driver help?

Link to comment

Update... So, I replaced my RFX3000 with an RFX5000 last night. The two units are identical in size, shape, and operation except that the RFX5000 has two additional inputs.

Good News: my static noise was reduced by the new head unit!!!

Bad News: the controller cable that connects to the MaliView causes a hum on my sub when it is connected. :( If this cable is disconnected the hum disappears. I suspect this is a gound loop issue (not my previous static noise issue), since the MaliView receives power from the the driver's side of the boat. Plus, I think a hum is more consistent with a ground loop problem than static noise that is just a little louder than it should be. For now, I've just disconnected that input cable which means I can't use the MaliView to controll my stereo, but I still have the helm remote control so it's not a big loss. The only real feature I liked on the MaliView for controlling the stereo was the MUTE button. I can't find a mute command on the helm stereo remote control.

Does anyone know of a solution for this problem? I've heard of people mentioning isolators. What are they and would they work in this scenario? The connector to the MaliView is via a remote module mounted up and to the right of the HU on the amp board. Could I filter the RCA sub outputs on the HU? The hum is only on the RCA sub outputs...

Edited by Cory
Link to comment

I am no stereo guru at all, but I had this same issue with my new system. Took it back to my installer and he tested all ground loops, connections, etc and could not figure where noise was coming from. Mine was when boat is running and volume turned all way down. He bypassed the rca cable going through bow area and it went away. The problem was corrected by simply rerouting rca cables under the helm. They were bundled up on the MTC side, he routed them behind heater on the head unit side and the noise is completely gone.

Not sure if this might help you out. For some reason the rca cables were getting interference from that side of the helm area.

Link to comment

Ground loop with the engine off??

You know something I read in another thread..... someone had a similiar noise issue with the engine off.

They tracked it down to the male RCAs being a little too long into the back of the EQ (I know hahahahh enter all the jokes)... in that they were making good contact on the RCA terminals.... but they were pushed in so far in on the female RCA that the outter part of the male RCA was touching the outter chasis of the EQ and grounding out.... causing the noise.

Another quick 30 second thing to check... twist and pull all your RCAs 1/16" or so back off their terminals to rule out your male parts not being too long :rofl:

Link to comment

RCA's should always be routed away from the boat electronics, especially the computer up under the dash at all costs. Also make sure that when you are adding splitters/y's etc to your rca's that you tape them up so you don't have any metal exposed when stuffed behind the amp board. Just another potential noise source to eliminate while you're at it.

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...