3rd gen amp/sub issues - grounding point?

t4rain

New member
Does anyone know of this would be a good location for an amp ground? I don't have a multimeter yet - will check it when I get one. This is dremeled down to remove the paint on both sides of where the metal sandwiches the terminal so it should be a clean contact point... It is the smaller gold screw on the passenger seatbelt.

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4C82C324-73E4-44A5-9229-77EADECD7D4E-3638-0000018CCE7CC378.jpg~original


The amp is a jl jx360/4 and I currently am having issues powering a jl 10wx sub. I have tried different RCA cords from my head unit (jvc kdx50bt) to amp and the speaker slightly moves when bass plays but doesn't produce much sound at all. Crutchfield said it was probably my ground so I changed it to a rear seat bolt (sanded paint) and same result. When I toggled the 4 channel/2channel amp toggle I hear a quick boom from the sub (that sounds how it should) so it seems to get power to it and I have tweaked the gains from 0 to full with no change in volume. I have also made sure it was set up correctly in my headunit and have played with the hpf/off/lpf switches on the amp. I haven't bothered with the speaker install yet. Any help is greatly appreciated. Thanks!
 
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When looking up your manual for the radio looks like you need to check at least three things.
L/O mode- line out mode. Select if the REAR/SW terminals are used for connecting the speakers or subwoofer. SUB.W: subwoofer , REAR: speakers
Sub.W- sub on or off
Sub.W level- 00-08, adjust subwoofer output level

The second two adjustments will only show up if L/O mode is set to Subwoofer.

SUB.W lpf- adjust the sub frequency , adjust this after you get it working but you will probably want to set to 55 hz
 
How do you have the woofer wired to the amp? It's 90x4 assuming good voltage and if you don't have it bridged properly you won't get much output... How about posting a picture of the adjustments and wire connections for the amp
 
That is a terrible spot for a ground.
(Edit...) actually is not that bad I guess as long as you and the sand off.

I used the rear seat belt mount against the metal body . Both the center and drivers side mount.

Remove the drivers side far seat belt mount which is near the door. Scrape away all the paint down to bare metal. Install between the washer and body. Repeat for center seat belt if you need a second ground.

Also you will want upgrade you battery neg to chassis cable.
 
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definitely need to fix your ground.

Also check the sound filter on the amp, there is generally 3 options
LP:AP:HP. Low Pass (LP) is what your amp needs to be set to for a sub.
 
R34 – thanks, those were all set correctly and I have made sure to set the lpf for 55 hz through the HU

Skidmarc – The first image below shows how I am bridging channels 3 and 4 along with the power, ground and remote on wires and the second image shows my settings (3 and 4 are the controls on the right – gain is set to max on that… only gets a tiny bit of power)



BrianSD – the bolt is too thick for the terminal connector and even the spade connecter that came with my kit. I tried to go to the rear seat bottom bolt but I had a hard time keeping the connector in place while trying to screw in the seat and keep the carpet hole in place. It didn’t seem to make a difference so I went back to the other spot. Anything beyond that bolt is too far for the ground wire that came with the kit. I have grinded down the paint some more on both pieces of metal touching the spade connector to make sure it is good contact

I tried to get one of the bolts behind it loosened to ground there but I couldn’t loosen it at all

Wheelds – it is set to LP but I might need to tweak the filter frequency on the amp – not sure where that should be set to. When you say “fix” your ground do you mean a new location or clean up the contact points?

Thanks for all of the help guys!
 
on the amp put the filter at off, and see if theres more sound, otherwise put on lp at 200, let the deck to the work.
also check the wires on the sub for loose connection, and check if you have a bad voicecoil.
 
That location should work for grounding the amp (though I would recommend bolting to a seat bolt or for mine I used the "D" ring bracket bolt in the cargo area).

For a simple test of the amp, disconnect your remote wire from the amp that is from the radio, put a jumper from your Battery + into the remote + terminal of the amp. Use a MP3 player with a headphone to RCA cord. Set the player @ a low volume, connect to the amp RCA In. Turn off the amp "filters" so it plays full range. Increase the volume as needed & you should get sound. If you do then you'll probably have to fool with your radio settings more and/or verify your RCA cable is good. If you don't have sound still then either your not getting enough power on the battery lead(+), your speakers are incorrectly wired in the box or maybe a defective amp.

ALSO if your using DVC's (Dual Voice Coil) speakers make sure you wired them correctly. If the speaker(s) are incorrectly wired the 2 coils will fight each other it will cause the spkr to have little/no movement .
 
You should only have two rca cables coming from the subwoofer out on the head unit to the amp. in this pic you are running all four in . It is only two out for the sub on the head unit the other two are for the front speakers out.
RCA should only be hooked up on channel 1 & 2 when running it in mono and speakers wires out to sub should be bridged out of 1 & 2 .
 
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