EXPIRED: FS: Broadband Acoustic Absorbers (4x corner traps)

fidelity4u · July 14, 2021

Further information:

The price for these is pretty well just the material cost. I need to move them on pretty quickly as I’m moving interstate in a few weeks. I’ll be building a new pair up there after I move.

If you can accept the lost space and slightly imposing nature of these (they look better in person) they are one of the best upgrades you can get for a full range system in a small/mid sized room. Given they reduce both room modes and comb filtering artefacts they tighten up the bass, smooth out the sound in the mids/highs and increase clarity and the perceived depth of the stereo image. Anyone who hasn’t tried acoustic treatment should. I love it obviously. Bang for buck, if you get the appropriate kind and placement, it is a bigger improvement than better interconnects, power cables, even better main components in a lot of instances.

I prototyped 9 configurations of corner traps before settling on these, a few others measured better in the low end but didn’t sound as balanced overall.

Please see a model of it’s absorption coefficient curve below:

Dimensions:

Depth is 580mm, length ~900mm and height around 1220mm each.

Absorbent material used is mostly Bradford SoundScreen insulation but also Kauf equivalent Accoustic insulation. Both have a similar flow resistivity perpendicular to their front face 12000-14000 RAYL. However, in the horizontal position as constructed about 6000 RAYLs from memory, which is better for bass absorption in such a thick absorber.

Frame is made of pine and Baltic birch ply from memory and is reinforced with flatscreen mesh. Also 1” Dacron covers the visible faces of the absorber to prevent any insulation hairs sticking out in the future. They are cloth covered on all sides accept top and bottom which is ply. The cover cloth used is as acoustically transparent as I could find. Side covers facing walls are lower quality fabric.

Photos: