So recently, my subwoofer will suddenly get very loud all of a sudden in the middle of a song. It will be fine for a while, then suddenly its like the bass boost was turned up 10 notches. If I let the car sit for a while, it will be fine again. I noticed the amplifier is hot to the touch, but it doesn't feel abnormally hot.

I've had the JL 10W6v2 and JL 500/1v2 combo since Febrary and this is the first time I've had a problem. I'm not sure what to attribute this to. Possibly weather change? Granted I'm in FL and it has been getting in the 90s with my car under the hot sun all day. Can overheating cause this? Is one of my wires loose? (I would think a loose wire would cause crackle or no sound) I really don't wanna blindly sifting through the whole setup without some ideas to go on.

Thanks ahead for any help.

 

Oh yeah. Forgot to mention...

This is in a ZEnclosure box. So its not like the amp is under the carpeting with hot air. Both the sub and amp are straight up in the open trunk.

 

How are you sourcing your subwoofer signal? What pins on what connector have you tapped off? Do you have anything between the HU and JL Amp?

 

I'm tapping pins 23-26. There is nothing b/t the HU and JL amp.

I did notice something odd. When the temperature went back down a little bit and this occurred again, I turned the bass setting on the Bose HU to max then back down to 0 and it fixed the issue. Not sure what that could have done. I still have a gut feeling this is temperature related.

 

It's your electrical. What's happening is the heat is causing the alternator to not put out the voltage it does normally, causing a drop in resting voltage. This causes clipping which explains the booms because the amp is struggling to maintain power with such a low voltage level. What I suggest is adding a battery back there to give it excess amperage to keep it powered.
Also check your fusing and I suggest picking up a stinger voltmeter to keep track of the voltage because 99.9% of amp problems are related to voltage issues.
Winter is always going to be easier on the electrical, you will see higher voltage in colder temp compared to higher temp.
Electricity + Heat=BAD

 

Well, its not really clipping per se. Its more like someone increased the gain and it stays constant at that increased level. But I would think that such a situation would increase draw from the amp. Plus, I'm using an Optima YellowTop which is deep cycle.

You're right though, I need to check my voltage. Maybe that's the next step if this keeps happening.

 

That's what clipping is my friend. Dirty powering the sub will cause strange booms. The amp is not able to produce clean power with lack of car voltage backing it. A common misconception is clipping occurs only if the gain is set wrong, but that is incorrect.
Clipping can occur from:
1. Too low voltage
2. Bad Ground
3.Poorly set gain

Since your system worked fine before, I ruled out 2 & 3 and thus your issue should lie in low voltage.

 

Gotcha! Thanks.

 

Oh and for the solutions:
1) new H/o alternator (DC Power FTW!)
2) or high quality starting battery XS Power D1200
3) add a battery parallel to the amp

 

What are the advantages of this over my Optima YellowTop?

Also any idea on why the problem fixes when I turn the HU bass to max then back down? Wouldn't that create a greater draw and theoretically make it even boomier?

 

While that is a nice battery, I just does not have the amperage a XS 1200 does. These batteries can put out up to 1200A while the optima top out at 700ish. Plus it is cheaper haha

And that's in essence tricking the ECM into what amperage you want through the system consistently. The amperage through the amp is topped out at whatever the set draw is, it will take in no more than it is fused for on the amp. So the bass setting on the HU has nothing to do with the problem.

Also, how did you set your gains? Did you use a DMM?

 

For #2, corrosion around the grounding point could be a possible problem...although it's most likely not an issue for you, it wouldn't hurt to check your ground.

 

Corrosion would not occur that fast, it takes years or water leakage, which I doubt would be happening with JLai's brand new car haha

I've never used a JL Amp before so I am not quite sure how different they are in terms of performance & efficiency but I strongly believe my hunch is correct.

 

I have no idea why the bass setting fixed it then. Almost makes me wonder if there's something going on within the amp.

I set my gains using a voltmeter and this guide...
JL Audio - Car Audio Systems

 

Re do the gains maxxing out the bass ****, and setting the HU settings to how you listen to them daily, and the volume 5 notches from the end. Then set the gain, this way you're voltage will be exactly what you see on the DMM and won't change as the settings on the HU are changed.