John Sayers' Recording Studio Design Forum Archive

Semi-theoretical/hypothetical question, but semi-practical application also, since I'm designing the room now:

Besides the corners (wall/wall, wall/ceiling, trihedral, etc.) are there ideal locations for placement of bass traps that relate to room dimensions and/or speaker distance?

i.e., is it preferable to locate bass traps at the antinodes of the primary axial modes? or at the nodes? somewhere else unrelated to modal behavior?

Or for most broadband bass trapping is location not so critical?

(This presumes there's already some bass trapping in the corners.)

Thanks.

Besides the corners (wall/wall, wall/ceiling, trihedral, etc.) are there ideal locations for placement of bass traps that relate to room dimensions and/or speaker distance?

Not really, although it depends on the type of trap. If it is velocity based, then corners are the best place for it. Tri-corners first, followed by two-surface corners. Pressure based devices can also work up against the walls, and resonance-based devices could work when placed at pressure nodes, but simplest and most effective is velocity-based devices in the tri-corners.

i.e., is it preferable to locate bass traps at the antinodes of the primary axial modes? or at the nodes? somewhere else unrelated to modal behavior?

Depends on what the purpose of the trap is. Axial modes are just one aspect of what bass traps do: there are also tangential modes and oblique modes, plus general bass build-up, and other issues. If the trap is targeting a specific axial mode, then it has to go either at the pressure node or the velocity node of that mode, depending on what type of trap it is.

Or for most broadband bass trapping is location not so critical?

Broadband bass trapping should still go in the corners, since the corners is where all modes terminate.

This presumes there's already some bass trapping in the corners.

In ALL of them? Don't forget that there are twelve corners in a room: if you have heavy broadband trapping in all twelve corners and there are still serious modal issues, then there's something pretty basic wrong with the room! Is it a perfect cube, for example?

- Stuart -