Bass trap question.

[drew.n]

Soo "everyone knows" that "it doesn't matter where you put your sub, because deep bass is non-directional"
Bottom E on a bass guitar having a 28 foot (ish) wavelength, bears this out to some extent

Also everyone knows that a room is should be symmetrical and that bass likes hanging around in corners.

So the question is this:
If you had a small room about, 4.5m x 2.5m, that was an odd shape

ReadyMadeBassTrapPerhaps.jpg

Would it work to fill the shaded area with hangers (what with the entrance bit being off to one side), or would it be better to block that off and use that as storage space?

[Soundman2020]

"it doesn't matter where you put your sub, because deep bass is non-directional"

Actually, that isn't true. Correct, bass is not directional, but that does NOT mean that subs can be placed anywhere: it means they can face in any DIRECTION, with very little difference in the sound field in the room, but speaker PLACEMENT is very important. The room will sound very, very different for a sub placed at ear height in the middle of the room, as compared to the exact same placed up tight in one of the corners. That makes a huge difference.

The fact that bass is non-directional means just that: it spreads out evenly in all directions from the source, unlike high frequencies that tend to travel in "cones" or "beams". But the location of the source still matters: it's the orientation doesn't matter.

Also everyone knows that a room is should be symmetrical and that bass likes hanging around in corners.

Only the front half needs to be symmetrical, and that assumes we are talking about a control room. If we are talking about a live room, then symmetry is no required, and in fact can even be detrimental, under some circumstances. Non-rectangular, non-symmetrical rooms are usually better for live rooms and booths.

bass likes hanging around in corners.

Weeelllll.... Yes and no. That's the way it is often described, with terms like "bass build-up" and suchlike, but it's actually a bit more complex than that. For example, all room modes terminate in corners, so that's the best place to put bass traps to treat them, and bass sounds louder closer to surfaces because of the pressure rise and long wavelengths. But if you cut a huge hole in the corner, as shown in your diagram, then there is no surface against which the pressure could build up!

Would it work to fill the shaded area with hangers (what with the entrance bit being off to one side), or would it be better to block that off and use that as storage space?

I suspect that would work more or less as a Helmholtz resonator, and it would be tuned to a very low frequency, I reckon, depending on the dimensions. It would work to some extent as a bass trap, but it is basically two separate but coupled acoustic spaces, and the unknown factor is the manner in which they are coupled.

It might be better to use that as storage, or even as an iso booth, if it is big enough.


- Stuart -

[drew.n]

Ah. OK that all makes perfect sense.
It's not big enough for a booth, at least not with any treatment.
At the moment I'm thinking of a single room with gobos, occasionally used for tracking music, but also a big chunk of spoken word.

I'll start a thread later, It'll be a while before I can get to the first step of a test.

Meanwhile I'll take some proper measurements and break out Sketchup.