Advice sort from Dave at Earmark

[BumbleBee]

My boat is currently having a refurb , she's totally gutted , no seats , dash board , have total access to wiring .

I have a 2008 VLX , factory JBL black box unit (3.0 I think) installed . 4 x Polk Audio DB651 running off the factory wiring . 4 x Rockford Fosgate Power speakers (soon to be replaced with Polk's) mounted on the tower running off 1 x Rockford Fosgate P400-4 amp . 1 x Rockford Fosgate P400-4 amp powering 1 x Rockford Fosgate P2 sub & Sony Xplod 1500w sub (bridged) .

Head unit is factory wired . Amps are wired directly to battery (positive & negative with inline fuse , two set of power cables) , remote to black box , plugged into RCA jacks on black box . Amps are placed on bulk head underneath JBL black box . Battery is located in rear LHS locker above drain pump for ballast tank .

I followed the wiring instructions in the Rockford manual .

Questions:

# Should I have the Amps powered this way ? should I run a single positive & negative from the battery up to a power block then take power for each amp off that block ?

# Should I run negative this way ? Should I run negative around front of boat and back to factory negative block under throttle panel ? Again a singular negative back to negative block then splitting off to amps ?

# Out of the two subs , which is the better one ? I'm thinking of removing one ? I had one in the observers locker (p2) , the Sony was behind the kick board drivers side , or should I keep both and cut Sony into front of kick board ?

# Last few times we've been out , I have noticed a slight speaker/interference noise coming from tower speakers ? Any ideas on this one as its never done it before ?

Whilst everything is out I'm removing any electrical connector and soldering and shrink wrapping . All the extra speaker wiring that is not connected I'm cutting off connectors & shrink wrapping to try avoid corrosion/interference .

From memory the subs are set to let the low/base freq through & and towers to all pass . I'm not a tech head with this stuff (freq ranges etc) so I set it the old fashioned way , turn up volume of head unit with amps turned down , find the distortion range then back it off till it stops , then bring in the amps one by one .

I removed the netting and the parcel box/shelf thing in the walk through in order to let the sound escape.Rob

[Earmark Marine]

Rob,

Some of this isn't written clearly enough so I'm not certain that I am interpreting everything correctly.

From the battery positive and negative you should have a single large gauge (fused very close to the battery) positive and single large gauge negative going in the most direct route and terminating closest to the amplifiers. At that point, very close to the amplifiers, you can use distribution blocks to divide into smaller gauge jumpers to each amplifier. From this point of distribution, close to the amplifiers, you should connect the supply and ground for all source electronics. Do not use the factory helm buss. This means the power for the Black Box will no longer be sourced from the factory harness. Do not take the source supply and ground directly to the battery since the battery is removed by some distance from the amplifiers. The most critical point of low resistance reference is between the components in the signal path so make that point of reference closest to the largest amplifier. And, the heavier gauge of supply/ground the less likely the draw from larger components can modulate the supply of the smaller draw components. This recommendation along with properly set gains should eliminate most forms of noise.

One subwoofer location is usually best because it eliminates any potential for phasing conflicts. Two subs will generally play a little louder but sacrifice musicality and you do not get the same efficiency as you do with a single sub in .the most optimum location/orientation. The right sub enclosure is essential. A driver is only as good as the enclosure and it is the enclosure that will be mostly responsible for the deep bass extension.

Those are a few of the basics. Hope this helps.

David

[BumbleBee]

Ok Dave, l'l start from the beginning ;-)

BOAT:

2008 Malibu VLX WakeSetter

COMPONENTS:

Factory JBL Black box which power 4 x factory installed speakers (Polks).

2 x Rockford Amps (both 4 channel) one amp powers two subs (as you stated above I will remove one) the remaining amp powers 4 x Rockford tower speakers (soon to be replaced with Polk).

1 x Rockford Sub (a P2, it is preinstalled in its own sub box).

SET UP:

From the battery (located in Port side rear locker next to engine bay), Two sets (positive & negative both heavy gauge) leads both with fuses on the positives located near the battery run along the port side and are zip tied to factory wiring harness terminating under the port side dash panel (glove box). Under the port side dash panel (glove box) is where the factory installed JBL Black box is mounted , directly on the underside of the dash panel (glove box) . On the bulk head under the dash panel is where I have mounted the 2 x Amps. The power leads connect directly into their respective Amp. One Amp will now power one Sub, the other Amp will power the 4 x tower speakers. From memory the Amp that is powering the sub is set to 2 channel (as I said above I was running two subs) it is also set to let low freq pass. The amp which powers the tower speakers is set to 4 channel and set to let all freq pass.I used the old school method to set the gains. Set gains to minimum then increase volume on HU untill distortion heard, then back off till it stops. Then bring up the gains one by one of the Amps.

So from what you said.....

Run a single power lead with fuse next to battery up to a power block (need to purchase power block & negative block) located as close as possible to the Amps. Run power for HU from this power block, not the factory wiring harness. Run the negative for the HU to the negative block. Will this way of wiring up the HU affect the way it turns on through the MUX switch located on drivers dash board next to steering wheel ?.

If you can see a better way using components I have, please let me know.Regards Rob

Edited May 15, 2012 by BumbleBee

[Earmark Marine]

Rob,

You can use an interrupt relay to bypass the factory harness and still maintain the factory switching scheme.

David

[BumbleBee]

Ok, what is an interrupt relay and what does it do ?

[Earmark Marine]

Rob,

The supply for the source electronics comes directly from a common point with the amplification which means it is continuously hot. The output of the MUX switch controls the relay and interrupts the supply. So even though you have a new power source, the switched operation functions exactly as it did before.

David

[BumbleBee]

Hi Dave, could you give me an example how to wire the relay....87....87a...86...85...30...

Edited May 16, 2012 by BumbleBee

[D-GOOSE]

Google is your friend. Maybe call David to speed this install up and so you can ask all the questions at once.

[Earmark Marine]

Thank you video.

[BumbleBee]

Dave, thanks for all your advice, very much appreciated :-).

Goose, thanks for the video :-).

Now to rewire the stereo....

Rob

[BumbleBee]

Got another one for you Dave....

Series or Parallel wiring for speakers.

I've dropped one Amp, sub bridged off the rear channel . I read an article buy a guy stating the pros & cons of wiring series or parallel.

How I understood it... Series, simply add the ohms together and stay at or below some magical figure of 16. The Amps runs a little easier, better acoustically . Does that imply you could turn the gains up further on that Chanel ?

Parallel, basically if you have two 4 ohm speakers, wiring them would reduce to 2 ohms. Which i understood meant your Amp works harder, more boom for your buck, but the Amp will also run hotter.

Your thoughts ?

Rob

[BumbleBee]

The vid worked a treat for the relay wiring goose, thanks again.

[Earmark Marine]

Rob,

There may be some information in that article that isn't applicable to mobile electronics and may be taken a little out of context.

State what amplifier(s) you have, the woofer voice coil configuration plus the quantity and make/model/impedance of your coaxial speakers. Then it will be easier to explore what options pertain to your system in particular.

David