Bottlehead Forum

General Category => General Discussion => Topic started by: aragorn723 on August 29, 2024, 04:54:25 AM

Title: help with subwoofer
Post by: aragorn723 on August 29, 2024, 04:54:25 AM
So i'm running a B&W 10" subwoofer from the output of my sub.  The amplifier output is wired to the subwoofer speaker level inputs, and then the speaker level outputs feed the main speakers.   When it is playing music, the subwoofer isn't on all the time and is supposed to sense the signal and turns the sub on/off automatically.  For some reason the sub is cutting out in the middle of a song, any idea why this would be and how to fix it?

Dave
Title: Re: help with subwoofer
Post by: Paul Birkeland on August 29, 2024, 05:26:45 AM
If there's an auto on/off feature, maybe it can be turned off on the woofer amp?
Title: Re: help with subwoofer
Post by: aragorn723 on August 29, 2024, 05:43:05 AM
If there's an auto on/off feature, maybe it can be turned off on the woofer amp?

It does, I was hoping to leave it on so it would be one less switch to turn on/off when playing music.  Is there another solution?

Dave
Title: Re: help with subwoofer
Post by: Paul Birkeland on August 29, 2024, 05:45:38 AM
The woofer should have an "always on" setting, and I would just use that.
Title: Re: help with subwoofer
Post by: aragorn723 on August 29, 2024, 06:58:45 AM
Paul,

I turned off the auto feature and switched to on.  That should have fixed it, but it seems like it is still missing some of the hits.  Basically it hits some bass notes (on a familiar track) and misses others.  As far as I can see it still has power to the sub amp, maybe the speaker wire loosened inside on one of the speaker terminals?  As far as I can tell the sub is still getting a signal since the main speakers aren't cutting out.  Any other ideas?

Dave
Title: Re: help with subwoofer
Post by: Paul Joppa on August 29, 2024, 08:00:47 AM
If you have a high-gain main amp and/or high sensitivity speakers, the preamp may not be set to a high enough output voltage to trigger the turn-on.

I doubt that this is the problem though. Auto-on sub amps typically stay on for a while once they are triggered. I looked up a typical one, and the manual said the trigger level is 10mV and the turn-off time is 15 minutes.
Title: Re: help with subwoofer
Post by: aragorn723 on August 30, 2024, 03:14:39 AM
Makes sense.  10 mv isn't a lot of current.  The woofer seems to be ok mechanically (it moves smoothly thru it's xmax when I gently press evenly around the cone).  Seems like there is an intermittent connection somewhere.  At least I have a backup sub laying around while I play with the B&W.  Unfortunately it is from 2005, so age is working against it too.  It might not be worth sending to a repair shop if I can't figure it out.

Dave
Title: Re: help with subwoofer
Post by: 2wo on August 30, 2024, 06:11:06 PM
Do you have the option to reconfigure to run the sub from the amp (speaker) output rather than the Quickie?
Title: Re: help with subwoofer
Post by: aragorn723 on August 31, 2024, 06:24:42 AM
I'm actually running the sub from the speaker output and the speaker level outs from the sub to the mains..  Oddly enough the sub worked perfectly yesterday, gonna take the woofer out today and see if a wire is loose.

Dave