Bass Traps

[TommyC]

I currently have my Heresies about 5' out from the back wall and almost 4' in from the side walls. A few minutes ago I was in the corner behind one of them chasing a kitten who looked to be on a mission to claw anything he could find and I noticed that the bass level was a Lot higher than out in the room. Would I see improvement in my listening position by using some sort of bass traps in the corners Behind the speakers? I am sorry if this is basic stuff, but room treatment is Way beyond me at this point.

[PrestonTom]

Yes, it is a good obeservation/question!

At very low frequencies much of the level you receive at the ear is very much a function of room geometry/acoustics.

With very long wavelengths, drapes, furniture and carpets do very little to break up the low frequncy waves. Consequently, what you heard (the increased level) was due to standing waves. Bass traps (usually placed in the corner) are one of the few ways that you can even out the sound. So that is a possibility.

The other major approach is to experiment and move the position of the speakers (mostly relative to the floor, if they are on risers, and relative to the rear and side walls). This will certainly impact the imaging & sweet spot however. Additionally, when you re-locate the speakers it will not typically reduce the uneveness of the low- frequency repsonse. Rather, it will shift the loud & weak spots to a different frequency region (you will still have standing waves).

Good luck,

-Tom

[DrWho]

woh there, I'm running the numbers off my head but 4 feet is 1/4 the

wavelength of about 75H and 5 feet of about 65Hz....what this means is

that a reflection off those walls that returns to the speaker now

becomes 1/2 wavelength out of phase with the direct sound...180 degrees

out of phase means lots of cancellation...right in the most noticeable

bass region too! I can see how their current position is good for

imaging so perhaps you might want to invest in a subwoofer (perhaps

tucked away into the corner). Your other option would be to move the

speaker around. I would try to avoid putting a bass trap in those

corners simply because that is a lot of bass energy that could

otherwise be projected towards the main listening position.

I would recommend installing some curved masonite panels behind the

speakers and tucked into the corners (if it's aesthetically acceptable

in your situation). If you don't get the kind of bass response you

want, then I would try stuffing the space between the panel and the

corner with some absorbtive material (thus going back to the bass trap

approach). You could build a pair of masonite panels for like $40 which

would be way cheaper than the typicall comercialbass trap route.