Car subwoofer suddenly very quiet

[Bopop4]

About a year ago I bought an Alpine CDE110 deck and some speakers for my car, and a month ago I bought a subwoofer and amp as well.

Everything was working fine until a few days ago when the sub lost almost all its bass.

I've checked the power cable, ground wire, RCA cables, and the remote line, and they're all fine.

I took the sub in to the place I bought it from and they hooked it up and it seemed to be working fine.

Each RCA gives soun by itself but it's very weak, I've also checked all the settings on the sub and deck and they are the same.


I've been at this for a few hours and am thinking of paying someone to have a look at it, is there anything else I can do before I take it back to the shop to be inspected?

The sub does turn on and work, but it's very quiet.

Thanks.

 

[Jet Badger]

You could try connecting the amp to a different source like a phone or anything that has an audio output, see if that makes any difference. If it does, then you know the problem is in the line cables or the headunit. If not, you can always recheck the power cables, also jump the remote directly to 12v to dial that out aswell.

 

[TB]

Almost sounds like the deck is the sole source of audio. Is a fuse blown in the subs amp?

 

[Bopop4]

You could try connecting the amp to a different source like a phone or anything that has an audio output, see if that makes any difference. If it does, then you know the problem is in the line cables or the headunit. If not, you can always recheck the power cables, also jump the remote directly to 12v to dial that out aswell.

I already tried different cables.
I hooked it straight up to my phone and it gave more bass than before, but then the sub suddenly shut off and it won't turn back on again. I've checked both fuses and they're fine.

Almost sounds like the deck is the sole source of audio. Is a fuse blown in the subs amp?

Fuses are fine, and the sub was working in the store.


Now the power light won't even come on, but I know it's getting power.

Edit: Can a fuse be blown without it looking like it's blown?

And what causes a fuse to blow when it's been working fine?
I don't want to put a new fuse in and have it instantly blow because there is some other problem.

 

[Jet Badger]

You can check the fuses with a multimeter or any sort of continuity tester (a small battery, an LED and some wire would do aswell).

Fuses blow when the current flowing through them is higher than they're rated for, most of the time it's due to a short-circuit.

 

[Lewis_Hamilton_]

How is the amp/sub being grounded? I had a big fat earth cable screwed directly to some bare metal at the rear of the car's chassis to ground my sub, after about 2 years the amp started to do safety shut offs when drawing a lot of power. I repositioned the earth cable and screwed it to a different area of the car's bare chassis and that fixed my problem.

 

[Bopop4]

How is the amp/sub being grounded? I had a big fat earth cable screwed directly to some bare metal at the rear of the car's chassis to ground my sub, after about 2 years the amp started to do safety shut offs when drawing a lot of power. I repositioned the earth cable and screwed it to a different area of the car's bare chassis and that fixed my problem.

There's a bolt holding in some trim that leads to bare metal. I tested the cable and the bolt itself for resistance and they were both fine.

It's only been hooked up for about a month or two and was working fine, and the bolt was screwed in pretty tight.

 

[Lewis_Hamilton_]

Try bolting the earth cable to another part of the chassis, that isn't close to any painted metal or trim. Screwing it to the floor area of my boot/trunk, behind the rear seats and in front of my spare tire well did the trick for me, it was all bare metal around there.

If that doesn't work then you can at least rule out an earthing problem and only takes a minute to try out.

 

[turbolefty78]

You stated that the sub works when removed from vehicle and powered up in the store. Ok, so go the other way with the diagnosis, since you've only done it halfway. Try swapping in a known good(different from existing) sub into your car and see what happens. That will pinpoint if it's speaker or amp/head section. Yes, fuses can be blown and not appear to be. Cheap insurance is all they are so go ahead and put a new one in. If it fires up and then goes quiet right away, there's a problem in the amp. Electronics don't last forever, and car amps take more of a beating than home systems do, especially the high power sub amps.

 

[Bopop4]

Turns out my grounding point wasn't too great, it was giving enough of a contact to get the power light to come on, but not much else.

Try bolting the earth cable to another part of the chassis, that isn't close to any painted metal or trim. Screwing it to the floor area of my boot/trunk, behind the rear seats and in front of my spare tire well did the trick for me, it was all bare metal around there.

If that doesn't work then you can at least rule out an earthing problem and only takes a minute to try out.

What eventually happened was an entirely new hole got drilled right beside my original location, so now it has a dedicated grounding point.

I should've realized that it was the ground when it the sub wouldn't turn on and the fuses were fine, all part of the learning.

Thanks for your help everyone! I have my unce back.