Does unplugged subwoofer in corner trap bass?

nodiak · « **on:** 21 May 2006, 01:09 am »

If it's "unplugged" is it ~ bass trap?

Here's the situation. I have a 2 channel system, speakers are out from front wall ~ 5.5 feet.
I play a dvd/movie a couple times a month on a seperate "HT" system, in the same room. I am just setting this system up, making new speakers for it - sats with stereo subs.
The HT subs could be placed in the front corners = out of the way and more bass effects.
This means can't put bass traps there for the 2 ch, so...

Will the turned off HT subs trap bass for the 2 channel system when it's playing? Or will they maybe even increase bass output. Or...?

Don
P.S. I think this is one of those ~ stupid questions that may lead to some interesting information.

Obsession Audio · « **Reply #1 on:** 21 May 2006, 03:06 am »

Quote from: nodiak

If it's "unplugged" is it ~ bass trap?

Yes, but not a very effective one. The drivers will vibrate to bass, and that does cost the room some energy, but 1) even a big sub doesn't have very much surface area relative to the room, so not much gets eaten and 2) drivers have a resonant frequency, and that's the frequency it will be most effective at eating: and it's probably not the same one you need eaten.

It won't do any real harm, but there's not much benefit there. Of course if you're talking about a huge IB sub array or something like that, with a lot of driver surface area, it might be a different story.

It might be fascinating to design a subwoofer that was also a tuned helmholtz resonator for a room. I'm not sure it's possible - I don't design speakers so I don't know - but it would have to be pretty big, and very carefully tuned to the room it was in. Probably not practical...

nodiak · « **Reply #2 on:** 22 May 2006, 03:34 am »

Well, not so interesting after all!
Thanks OA.
Don

BradJudy · « **Reply #3 on:** 22 May 2006, 03:43 am »

Quote from: Obsession Audio

It might be fascinating to design a subwoofer that was also a tuned helmholtz resonator for a room. I'm not sure it's possible - I don't design speakers so I don't know - but it would have to be pretty big, and very carefully tuned to the room it was in. Probably not practical...

From my understanding, that's exactly what a turned off sub would be - a Helmholtz resonator. It would be causing a response dip at the tuning frequency.

mgalusha · « **Reply #4 on:** 22 May 2006, 02:24 pm »

When I first installed the Meadowlark BH2's in my system I had two Vandersteen 2WQ subs sitting in the corners disconnected. I was not overly happy with the bass of the BH2's and was unable to get it to integrate well with the subs so I had disconnected them. Finally I decided to stop trying to get the subs to play nice with the Meadowlarks (they worked great with other speakers) and hauled the subs to the basement.

Not even thinking about it I sat down to listen after getting the subs to the basement. I was stunned at the improvement in the bass. The changes were not subtle. What had been thin and somewhat anemic bass was now fuller, deeper and tighter. In my system they caused a surprising amount of degredation.

nathanm · « **Reply #5 on:** 22 May 2006, 03:01 pm »

I suppose one could short the speaker to itself, or maybe have a solid wood speaker grille? Even easier: don't worry about it.