Subwoofer pop and thump

Danthus · 27 Oct 2015 at 21:57

My subwoofer randomly makes a pop/thump noise and the green light changes from green to red.

I have checked all the obvious stuff and replaced the RCA cable but it still happens.

Subwoofer is a Wharfedale Diamond 60 and the amp a Onkyo 414.

Any ideas?

danoliver1 · 27 Oct 2015 at 22:42

When you say randomly is it when its in use?

Danthus · 27 Oct 2015 at 22:43

Yeah, completely random.

danoliver1 · 27 Oct 2015 at 22:48

What you got the dials set to on the sub? You might have it set too high causing the sub to bottom out.

Danthus · 27 Oct 2015 at 22:49

Volume, Phase.

Two buttons, Auto On/Off and Phase 180/0

danoliver1 · 27 Oct 2015 at 22:52

Phase should be on 0. Crossover on max (set it to 80 hz in the onkyo). Volume should be halfway( then adjust level in the onkyo.)

Danthus · 29 Oct 2015 at 09:17

I have just put the opening scene from Saving Private Ryan on, the sub is on but the light is red, no mater what I change on the sub, there is no bass.

danoliver1 · 29 Oct 2015 at 13:40

Disconnect the sub lead just have the power lead in. Does the red light go out?

joeyjojo · 29 Oct 2015 at 13:45

Was randomly popping, now nothing? Doesn't sound good.

I have a Wharfedale SW150 sub which has a nearly-useless auto-on-off feature. The volume needed to trigger it on is ridiculously high, so I have it set to be always on. That might explain your "no bass" problem. Wastes about 40 W doing nothing which is annoying though.

Alternatively your receiver might need fiddling with. With mine, any of the "stereo" modes disable the sub, I need to use one of the processing modes (pro logic ii, etc.) to get it to send LF to the sub. Also worth confirming that the receiver setup has the sub "on".

Or it might have died. I had a subwoofer fail a few years ago. It was in storage for a few years and several capacitors had popped. Took it to a local disco hire place that had it repaired for me for about £80, can't remember exactly.

Danthus · 29 Oct 2015 at 14:22

99.99% sure it is the sub woofer, I have swapped cables etc.

The amp config hasn't changed so I can't see it being anything else.

Danthus · 29 Oct 2015 at 14:58

In for a penny in for a pound, time to take it to bits.

Rroff · 29 Oct 2015 at 15:01

joeyjojo said:
Or it might have died. I had a subwoofer fail a few years ago. It was in storage for a few years and several capacitors had popped. Took it to a local disco hire place that had it repaired for me for about £80, can't remember exactly.

Random thumps/pops does sound like a capacitor(s) going bad.

WILD9 · 29 Oct 2015 at 15:18

Had exactly the same symptoms on an old Mordaunt Short 309 sub. It was the auto on/off circuit, eventually it failed completely and even setting it to permanently on didn't work. I'm sure with some time / talent I could have bypassed the switching circuit but I had limited amounts of both. On the bright side the BK Monolith that replaced it sounds great...

Danthus · 29 Oct 2015 at 15:47

Well I have taken it to bits I have no noticed that one of the fuse holders is broken.

I can see four capacitors too, just trying to find a multimeter now.

lucid · 29 Oct 2015 at 20:38

OldCoals said:
I can see four capacitors too, just trying to find a multimeter now.

There's quite a few more than four capacitors.

What are you planning to do with the multimeter?

Danthus · 29 Oct 2015 at 21:55

lucid said:
There's quite a few more than four capacitors.

What are you planning to do with the multimeter?

There were four large easily accessible ones.

Rroff · 3 Nov 2015 at 02:08

Bare in mind those caps could be retaining some pretty hefty charge :S

Danthus · 3 Nov 2015 at 09:29

It seems to be working now, although it still does it, just nowhere near as often.

I am not that bothered as Santa will be fetching me a new Amp and Speakers I feel.