I noticed this problem starting about a week ago. My sub will lose output by about half and play like that for a while, then start pounding again. It doesn't seem to matter if the volume is high or low. I checked all the wiring going into the amp and everything is tight. Took the sub out of the box and recrimped everything.

I'm running the stock HU, an MTX RFL600D and a 10" Clarion SW1051. Amp is only running at 4 ohms (rated 300 watts @ 4 ohms). Stock electrical also. Lights don't dim at all. I've got a spare sub laying around, but it's a 12" and I don't have a box for it and no means to whip up a temporary box.

What's the best way to start eliminating what the problem could be? Would it be a bad idea to run the 12" free air for a few days to see if it could be the amp? Other than that I have no idea where to start.

Check the grounds.

- also, i don't rec. free air for that long, but that's just me.

Check the grounds.

- also, i don't rec. free air for that long, but that's just me.

Yeah, I thought maybe the ground. I had a shop do the amp install and they are pretty reputable, so I hope that's not the problem. The sub is just an old Adire Audio Shiva that's been in the closet for 5+ years. I was just trying to think of another way to test things out.

Check the grounds.

- also, i don't rec. free air for that long, but that's just me.

Yeah, I thought maybe the ground. I had a shop do the amp install and they are pretty reputable, so I hope that's not the problem. The sub is just an old Adire Audio Shiva that's been in the closet for 5+ years. I was just trying to think of another way to test things out.

If you had a shop do the install i beg you to check the grounds

There's no problem with running the other sub free air for a while to see if it's the amp. You just have to realize that the power handling will be drastically reduced. So if you keep the power to the sub down there's no problem. It could run free air forever with the correct power.

There's no problem with running the other sub free air for a while to see if it's the amp. You just have to realize that the power handling will be drastically reduced. So if you keep the power to the sub down there's no problem. It could run free air forever with the correct power.

Yeah, I was going to keep all the settings and volume way down.

Just checked the sub with a DMM and it's reading 3.6 ohms. Haven't had a chance to check out the ground yet.

I've had this problem several times. It's always been an RCA issue, or one of the coil leads on a DVC driver.

I also fixed a guys car last year who had a similar issue. Every time he would put his back seat up, the bass would pretty much disappear. Circuit city did his install, and when they installed the remote gain knob, they simply threw it down inbetween the back seats and after several months of opening and closing them, it caused a short in the wire, and hence the issue.

Yesterday I pushed my sub pretty hard on the way to work (about a 45 minute drive) with no problems. About halfway home this morning, it started acting up again. I started playing around with the bass knob and couldn't get it to adjust the bass at all. It was working just fine about 10 minutes before this happened. Just to be sure, I tested it out with about a dozen different fairly bass heavy songs, but still didn't notice any difference with the knob at minimum, maximum or anywhere in between.

I had that problem before with a knob and therefor just didnt use it at all, and dont use them nowadays since I dont really need them.

I had that problem before with a knob and therefor just didnt use it at all, and dont use them nowadays since I dont really need them.

The reason I got it was because I'm using my stock HU. Should I unplug it and play with the settings on the amp and see what happens?

Well, I've narrowed it down to two possible culprits. When I left for work yesterday there was still hardly any bass, and the knob wouldn't adjust it at all. I started messing around with the cable that hooks into the back of the bass knob, and BOOM, it start playing like it should. So, it seems like it's either the bass knob itself, or the bass knob cable. Figures, the one thing in my system that wasn't bought used is what's causing the problem.

Yeah the cord may not be getting a good connection with bass knob itself or amplifier itself or maybe the cord has a short in it. Jiggle the cord around where you said you pressed it in at and if it goes in and out the cord has a short in it.

Now I'm wondering if it was in fact my sub (the Clarion). I installed my 5+ year old Adire Audio Shiva this past week (prefab box, FTL, but it was hella cheap). I pushed it pretty hard all week long and never once lost output, and the bass knob didn't have any problems adjusting the bass level. Weird and now I'm totally confused.

With things like that which are on and off in weird intervals, it's almost always a bad connection. You probably just fixed the connection on the bass knob when you were messing with it before you put in the new sub.

Want to get rid of that shiva?

Just a thought. But if your running a stock H/U, then you more than likely have some sort of low level adapter installed in the vehicle to convert the factory speaker wires over to a more usable RCA connection. If there is a bad connection on one of those channels you will loose half power through your RCA jacks..........but it sounds like you may already have found the issue......Good Luck...

Want to get rid of that shiva?

If I had my SA-12 right now I would. Otherwise I'd be without bass until July (it's gonna be my birthday present to myself), and that would suck.

With things like that which are on and off in weird intervals, it's almost always a bad connection. You probably just fixed the connection on the bass knob when you were messing with it before you put in the new sub.

It still doesn't make sense that I haven't had any problems with losing output ever since I put the Shiva in. With the Clarion it was a daily occurrence. Another thing is that the week before I installed the Shiva, whenever the Clarion would start acting up, I'd start messing around with the bass knob cable and it wouldn't fix the problem. I'd just have to wait, and sooner or later it would start performing like it should. Then it would start cutting out again. It's just strange that I haven't had a problem with it for a whole week, where as with the other sub is happened every single day.

It really doesn't concern me too much since I haven't had any problems with the Shiva so far, but I had planned on selling the Clarion. If it is the sub I don't want to sell defective equipment, but I have no other use for it (other than taking up room in the closet).

Have you checked the coils with a DMM like Dan208 mentioned?

I've been really listening all week, and maybe it's just me, but it still seems like something is amiss. It's not as noticable with the Shiva as is was with the Clarion, but it still seems like there is some loss of output.

I think this weekend I'll unhook the bass knob and retune everything. Run it like that for a while and see if I notice anything.