Issues with under seat sub!

[Cbass419]

Hey guys, first post here. I've been out of the car audio world for a few years after having my first kid. Well now I'm sort of getting back in. I got a cheap rockville ss8p sub/amp for my 15 Odyssey for Christmas and finally had a chance to install it. I used the high level inputs. This is the first time I've even used these because I always bought new head units for my previous cars, but that's not an option here. So install was very easy. Ran an 8 gauge wire kit (per manufacturer suggestions), tapped directly to the speaker wires and everything seemed great. Did some quick tests in the driveway and all was perfect. I go for a drive a bit later and the sub starts humming really loud, and continued to do so totally randomly. Even when no music was being played. So I thought I had one of the speaker input polarity reversed. So I switched one and the humming stopped but then the volume was cut in half. If I left one input off completely, the humming stopped and I had full volume. Ok, fine, guess I'll run it like that. Well this morning, it started humming again. Anyone have any suggestions on why it's humming? If I turn the fain down pretty much all the way, it won't him, but then you can barely hear it.

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[Louisiana_CRX 5,000+ posts]

Hey guys, first post here. I've been out of the car audio world for a few years after having my first kid. Well now I'm sort of getting back in. I got a cheap rockville ss8p sub/amp for my 15 Odyssey for Christmas and finally had a chance to install it. I used the high level inputs. This is the first time I've even used these because I always bought new head units for my previous cars, but that's not an option here. So install was very easy. Ran an 8 gauge wire kit (per manufacturer suggestions), tapped directly to the speaker wires and everything seemed great. Did some quick tests in the driveway and all was perfect. I go for a drive a bit later and the sub starts humming really loud, and continued to do so totally randomly. Even when no music was being played. So I thought I had one of the speaker input polarity reversed. So I switched one and the humming stopped but then the volume was cut in half. If I left one input off completely, the humming stopped and I had full volume. Ok, fine, guess I'll run it like that. Well this morning, it started humming again. Anyone have any suggestions on why it's humming? If I turn the fain down pretty much all the way, it won't him, but then you can barely hear it.

It's most likely picking up some sort of feedback interference to be humming like that . Go over your grounds real well . It may be picking up some sort of ground loop .

 

[Cbass419]

It's most likely picking up some sort of feedback interference to be humming like that . Go over your grounds real well . It may be picking up some sort of ground loop .

Thank you! Feedback is the word I was looking for! That's exactly what it's doing. I'll change my ground and see if that helps out.

 

[Squirrel!]

Make sure the ground is 8 ga. as well.

 

[Cbass419]

Make sure the ground is 8 ga. as well.

So here's the weirdest part of this amp/sub. The wiring harness that came with it has maybe 14 gauge wire one it. I attached a stock photo of the harness. The directions recommend an 8 gauge kit. So a significantly bigger wire. The current location of the amp is about 4 inches from a ground bolt, so I didn't attach any of the 8 gauge wire and just grounded the lead from the harness straight to that bolt. So I'll add some 8ngauge and run it to a different ground spot and see if that helps out.

 

[Squirrel!]

What you circled is the hi level/speaker level input harness, not a power wire.

 

[Cbass419]

What you circled is the hi level/speaker level input harness, not a power wire.

It's everything. That harness has the power, the ground, and amp turn on, and the high input wires all in one single harness

 

[Squirrel!]

Dang. Well, then with the ground being right there, and an 8 ga. is feeding the 14 ga. positive, then the ground being 14 ga. and the body bolt is 4" away, it shouldn't have an impedance issue.

I can say this...I have had 2 unseat AIO subs and the amps are crap. One didn't even make it to the road, another dies 3 weeks after install. That was the end of my foray into AIO underseat subs. Sorry I couldn't have been more help to you.

 

[Cbass419]

Dang. Well, then with the ground being right there, and an 8 ga. is feeding the 14 ga. positive, then the ground being 14 ga. and the body bolt is 4" away, it shouldn't have an impedance issue.

I can say this...I have had 2 unseat AIO subs and the amps are crap. One didn't even make it to the road, another dies 3 weeks after install. That was the end of my foray into AIO underseat subs. Sorry I couldn't have been more help to you.

Any help is good help, so thank you! I'm gonna try to move to a better ground. The bolt I'm using is a small bolt for the center console. I'm gonna move it to a much bigger seat bolt, with some of the I gauge wire and see if that happens to help.

 

[Cbass419]

So I moved the ground and it was good while I tested. Then I take a drive and it starts the feedback again! No matter what way I hook everything up, the feedback continues. If it was constant, I would think it was an actual amp/sub problem, but since it's random, it makes me think it's more along the line of interference or connection problem? Maybe?

 

[Squirrel!]

Are the input cables in the same channel as the power cable?

 

[Cbass419]

Are the input cables in the same channel as the power cable?

It's all in the same plug. Here's how it is on the amp. And then the harness plugs into this spot.

 

[YourNameHere 10+ year member]

i would honestly just toss it in the garbage can.....sometimes you just cant polish a turd

 

[Cbass419]

Well after doing a lot of reading, it seems that the issue might be the active noise cancellation in the Odyssey. Apparently what it does is randomly sends low frequency pulses through the speakers to combat road noise. And since the sub is tapped into the speakers, it will get this frequency. Which would explain why it doesn't seem to do it while I'm testing in my driveway, but then does it while I'm driving. It's apparently a pretty well known issues in the Honda world, So I'm going to temporarily disabled it to see if that is the issue or not!

 

[Cbass419]

Well I disabled the active noice cancellation and that fixed it! Instantly stopped the feedback sound! Thanks for all you're help!