Inconsistent Bass - Strange Problem (SA-12)

[tetsballer]

Hello there,

 

I'm having a problem with my system lately (for the last few months) my sub woofer will get very quiet to the point where its output is just enough to tell it has power still.

The strange thing is that when I turn the volume up past the half way point on the HU and turn the bass knob up all the way up, the sub / amp wakes up and puts full power back to the sub and everything sounds great for a while.

Basically it seems like the sub / amp only likes being played at full power and turned up very loud.

 

This seemed to start happening after one of my tinsel leads snapped off at the solder point so I had to re-solder it. 

 

The amps protect light never comes on, and I have never seen it come on.

This seems to happen randomly and sometimes will go days without happening. 

 

Voltage at the sub amp is normal between 12-14v when this is happening, does it when car is running and when not running.

 

Prior to this the system ran fine with no issues with all the same wiring and HU.

 

 

So far I have checked the RCAs, power level, subs connections in the box, subs impedance.

This happens with different songs and with android auto and Bluetooth signals.

When the sub is doing this I have disconnected the bass knob with no effect to rule that out.

 

My 4 channel amp is running alongside the sub amp with no noticeable issues.

 

I have no idea what to try at this point besides re-doing the grounds just for the hell of it (they are bolted onto bare metal already).

I don't have a spare amp to swap out or I would try that next, I would like to be able to rule out the amp somehow.

 

Is there any way to tell if another one of the tinsel leads is going bad ?

 

System specs:
2014 Mazda 6 Sport

Single Sundown Audio SA-12 Rev3 D2 @1ohm
Rockford Fosgate R1200-1D (gain set with oscilloscope) - no punch / bass boost

Custom made box @ 35hz

Skyhigh 4 awg power / ground wires 
Stock alt (100A)
Odyssey Extreme Battery
 

Any help would be much appreciated!

 

Thanks,

 

 

[audiofanaticz]

I would probably go and check the tinsels. Pull the sub and check impedance with a multimeter, there maybe another tinsel issue besides what you visually seen last time.
Try a different sub even if its just some cheap sub to rule out the sub all together.

[tetsballer]

Double checked the tinsels today and they look fine nothing is loose or cracked. I guess I'll move my ground and see if that helps.

[tetsballer]

Here is a video showing the problem....

Each voice coil reads 2.0 ohm on the dot and when wired up in parallel reads 1.0 ohm. I was trying to find the sweet spot where it will actually start playing (around half volume), it loves to play full volume but acts very strange at lower volume. Volume was being increased and decreased very slowly this whole time.

[1point21gigawatts]

Are you sure the rca’s aren’t bad? I think it’s the rca’s. The cable is probably the only thing you checked. It still might be bad. How did you check it? Even when a rca cable reads correct voltage still doesn’t mean it hasn’t gone bad. Buy a new rca cable to see and if it doesn’t fix the problem then rule out the cable. There’s other things to diagnose with bad rca’s, like the outputs on the head unit and the inputs on the actual amp. Switch the rca’s from subwoofer to rear in the head unit and see what it produces. If there’s no change then you rule out the head unit. Then hook up a distortion detector to the amp with out the subwoofer present and play with the gain and see where it distorts. If it doesn’t distort then it’s the amp. If it does distort the you rule out the amp. 

[tetsballer]

I have the output from my 4 channel feeding the sub amp now with a different rca, it seems to be working a lot better I'll have to leave it like that and see.