Sub makes wump wump sound when turned down

[Ramblin MAn]

Looking to see if any of you guys know what the cause and solution is for a sub that goes wump wump wump when the volume is down. The amp is an older Pyramid, the sub is a sony X-plod. The amp has led level indicators and you can watch them pulse as the sub goes wump wump wump. Sounds like a heart beating.

[carlos318is]

How have you got it wired up mate

[Ramblin MAn]

It's bridged mono. Set to low pass. RCA outs coming from the radio running to the inputs on the amp. Not really a lot to tell you.

[AcSchnitzer318is]

I think he meant where are you pulling the ground/power from and where are the wires run.  Also what head unit are you running?  Where are the RCA's run?

[Ramblin MAn]

power to the amp is coming straight off the battery. The head unit is an older Kenwood KDC-V6017. It was what was in the car. The RCA cables are monster I think. Gold plated ends. RCA and power cables were already there so I just hooked them up to my amp and sub. Sub is brand new. Amp was on a shelf at the shop. The amp drives the sub just fine. Just at low and no volume I get a heartbeat. I'll play with the gain and see if that helps.

[drumad]

Your equipment could be the sole reason.  Pyramid and sony are the walmart of car audio equipment.

Does the sound work in unison with car revs?  aka ground loop?  I doubt it tho bc usually theyre associated with higher freqs.  

Playing with the gain, filters, knobs on that amp will be useless as that amp is pure crap.  If youre set on it then so be it, but if you want to upgrade then PM me and I can help you out.

<<<<<------- recovering audioholic

[AcSchnitzer318is]

^True, sony and pyramid are not the best brands for mobile audio.  But also being an audiophile/installer, I can say sound quality is usually 95% based on the install.  I am running a crappy sony amp in my other car on a JL 12w1 and have had no issues since installation.  Sound is pretty good as well.

Where is the ground picked up?  Have you checked the stock alternator grounding strap or the engine grounding strap?  Sometimes those Monster cables are directional (same with some Rockford RCA's), you may want to check they are running in the right direction.

[drumad]

^True, sony and pyramid are not the best brands for mobile audio.  But also being an audiophile/installer, I can say sound quality is usually 95% based on the install.  I am running a crappy sony amp in my other car on a JL 12w1 and have had no issues since installation.  Sound is pretty good as well.

Where is the ground picked up?  Have you checked the stock alternator grounding strap or the engine grounding strap?  Sometimes those Monster cables are directional (same with some Rockford RCA's), you may want to check they are running in the right direction.

very very very true about the install.  You can make any thing sound good with a thorough and quality install.  

I agree tho, you need to really check the wiring inch by inch and make sure everything is sound, secure, and proper.

[Ramblin MAn]

I'll check the wiring.

As for the quality of the sub and the amp, I'm well aware it's the cheap stuff. But it just needs to sound "good" not awesone. The e30 is one of the worst cars I have ever had when it comes to stock speaker placement and upgrade placement options. The only one I've had that's worse is the e21. At least my e30 has the passthrough for the skis cut through the rear trunk wall so you can actually hear the sub from the trunk. The e21 is solid.

Anyway, the next owner can upgrade the sound system if they want. I'm just trying to work out the bugs with this sub and amp.