Help needed for close-wall speakers [Archive] - Audio & Video Forums


View Full Version : Help needed for close-wall speakers

06-29-2005, 06:22 AM
Hi - I've to put my speakers less than 3 inches from the wall, which make the bass very boomy. Does someone here know if there is anything I can do to reduce this? perhaps I should put something on the wall or on the back of the speakers?


06-29-2005, 08:03 AM
Room treatments should help. Try some corner traps and/or hang a rug or acoutic tile behind the speakers. You're getting too much reinforcement so you need to absorb the waves. If your speakers are rear ported, you can also try plugging the port. Many speakers come with port bungs for near-wall installs such as yours.

Hope this helps.

06-29-2005, 06:36 PM
Pull them further from the walls -- or get speakers designed for near wall placement...even speakers designed for near wall placement may require treatments as Topspeed suggests.

06-30-2005, 05:51 AM
Pull them further from the walls -- or get speakers designed for near wall placement...even speakers designed for near wall placement may require treatments as Topspeed suggests.
Agree.Damn did I say that.

06-30-2005, 03:58 PM
If this is a home theater apllication, maybe you can tell your processor they are "small" speakers. Normally this inserts a low frequency filter and routes the lowest frequencies to the sub-woofer jack. Some receivers will even let you set the crossover frequency.

06-30-2005, 05:21 PM
If low end boominess is your main problem, then your only solutions are repositioning or going with an equalized subwoofer. This is because boominess is typically more induced by the room acoustics than the speaker itself. In a typical room, you will have direct and reflected waves interacting with one another. Because of the long wavelengths with low frequencies, interactions between the direct and reflected sound waves can result in severe alterations to the bass that differ from frequency to frequency. At some frequencies, this room induced effect will cancel out the bass, while at other frequencies the interactions will create huge peaks that make the bass sound unbearably boomy when the sounds hit certain notes. These effects will vary throughout the room, and repositioning the speakers can completely change how the bass sounds at your seating position.

Buying speakers "designed for" corner positioning IMO is a nonstarter because the corner reinforcement will vary with as the room dimensions change. Plus, I don't think you're out to buy new speakers anyway. If anything, corner placement for the main speakers is problematic in most situations because the bass reinforcement is not consistent and corners are rarely the best place for optimizing the imaging at typical seating positions (rule of thumb placements typically recommend positioning the front speakers no more than 60 degrees apart, and corner placement usually exceeds this angle).

The equalized subwoofer approach is appealing precisely because you can position the main speakers for optimal sound quality in the midrange and highs, without worrying about the bass peaking and cancelling that the room interactions create. With a subwoofer, you position the unit wherever the bass is most even and fullest sounding. By adding a parametric equalizer to the mix, you can further fine tune the bass and create a low end that's more accurate than just about any speaker can do on its own.

Acoustic treatments such as bass traps can be very effective because they help to keep the bass waves from getting reinforced in the corners and minimize the room interactions.

Positioning your speakers too close to the wall will create a lot of other problems, such as time domain distortions that make the midrange and highs sound harsh and unfocused. For these issues, you might want to try some acoustic panels or as topspeed suggested, hanging a rug behind the speakers to absorb the sound and keep it from reflecting off the front wall. These approaches will not do much for the bass waves unless you go with a very thick fiberglas panel or specially designed acoustic panel, but they will do a lot for the imaging and overall coherency of the sound.

07-01-2005, 06:32 PM
Gentlemen - thanks for the enlightenment.

I have a pair of Triangle Celius for listening to music in the bedroom (which I dont have space to properly position them). From your inputs, I think best solution is to put the system in another room, where I can have proper space for them.

And yes, the bass does sound weird - its giving me a headache.

Thanks again.