Installation help on 4 channel amp with sub/speakers

[Zripp 10+ year member]

Hello,

I recently got a JLCP108LG-W3v3 subwoofer for my 2000 honda accord. I already had replaced the 4 speakers with "cheapish" pioneers. I replaced the headunit, and later installed a 4 channel amp to power the speakers. Now my goal is to power the rear speakers off the headunit, and use the 4 channel amp to power the sub and front door speakers. I have been attempting to get them to work and I guess I just can't seem to get it right. I am bridging the 3/4 channels for the sub, have the amp in 3channel mode and I get sound out of my front speakers, but only a very very low (barely audible sound) from the sub. I really don't know what I am doing wrong.

These are the manuals for the components.

-hfi 55.4 (amp)

http://www.maxxsonics.net/manuals/hifonics/pdfs/Hifonics%20HFi%202010%20Amplifier%20Manual.pdf

-DEH 3200UB (headunit)

http://www.pioneerelectronics.com/StaticFiles/Manuals/Car/DEH-3200UB_InstallationManual1006.pdf

-JL Audio W3v3 (sub)

JL Audio CP108LG-W3v3 MicroSub™ slot-ported enclosure with one 8" W3v3 subwoofer at Crutchfield.com

Thank you in advance.

Click to read more...

 

[mylows10 5,000+ posts]

try turning the gains for the 3-4 channel part of the amp

 

[Zripp 10+ year member]

No real noticeable difference. Do I need Y-adapters for the 3/4 channels to make it a mono signal? The amp manual mentions using them, but I found that very confusing.

 

[All_Logix 10+ year member]

Your not by any chance trying to run the sub from the rear speaker preouts on the HU are you?

 

[Zripp 10+ year member]

I have 2 sets of RCAs from the HU to the amp, so I guess yes? the subs RCA's are plugged into the rear/sub output on the HU and channels 3/4 on the amp.

 

[All_Logix 10+ year member]

check in your options and see if there is a way to change the rear RCA over from rear to sub

 

[supermaxx123 10+ year member]

Even if you are running mono you can still use a left and right input for the sub. As stated, run either rear or sub dedicated rca's to channels 3&4 RCS inputs. Also make sure the sub is connected to the correct terminals that are used for bridging, usually both + termianls. Or try jsut running the sub off one channel to make sure there is an actual signal being sent, then just bridge it to double the power.

 

[Zripp 10+ year member]

Ok, miraculously, I had the gain on the wrong setting.. that's embarrassing. I had it turned mostly to the right, which I thought would be almost full power, whereas that was apparently just a little power.

However, one problem still remains. The front speakers and sub work and sound good, however I am having problems with the rear speakers. The rear speakers are running off of the HU and make a awful crackle/popping noise when the base hits. I have moved the ground wire 3 times thinking that that was the problem, and it makes no difference. Here is the kicker.. this only happens when the car is running. When the car is off, they work completely normally.

Any suggestions?

 

[BrownVanMan 10+ year member]

pico fuse?

 

[Zripp 10+ year member]

Hmm, I just looked that up. That could be the issue with the rear speakers? Even though they are the only ones not using the RCA's and at first glance looked like an RCA grounding issue?

 

[Zripp 10+ year member]

I tried the pico fuse fix of grounding the RCA's and that seemed like it helped a little, but not much. But here is some new info..

When I tried fading the sound to the rear so I could only hear the troubled speakers.. they sounded fine. but as soon as I return the fade close to equal, they start getting that crackling noise again.

 

[keep_hope_alive Premium Member]

I tried the pico fuse fix of grounding the RCA's and that seemed like it helped a little, but not much. But here is some new info..
When I tried fading the sound to the rear so I could only hear the troubled speakers.. they sounded fine. but as soon as I return the fade close to equal, they start getting that crackling noise again.

sounds like it's the front speakers then... turn the front speaker amp gain down.

or the subs are pushing the rear speaker cones and causing them to distort.

 

[Zripp 10+ year member]

sounds like it's the front speakers then... turn the front speaker amp gain down.
or the subs are pushing the rear speaker cones and causing them to distort.

I turned the front speakers gain down and it caused to noticeable difference in the crackling noise. I turned it completely down so I couldn't hear anything from the front speakers and got the same crackling noise from the rear.

For your second suggestion, how would that be tested or fixed?

 

[keep_hope_alive Premium Member]

Visually look at the speakers. if they are moving excessively, you know the issue is one of two things.

1. Subs are moving speakers, either remove the rears or enclose them.

2. The HU is giving the rears too much bass.

If you have any bass boost on, turn it off. Put bass blockers on the rear speakers.