fidelity4u Posted August 3, 2021 Posted August 3, 2021 Further information: These are corner velocity absorbers that are very large and effective at taming room modes down to very low frequencies, as well as echos at higher frequencies, due to their thickness of 580mm. I prototyped 9 configurations of corner traps before settling on these, a few others measured better in the low end (hybrid panel absorbers and velocity traps) but didn’t sound as balanced overall. Absorbent material used is mostly Bradford SoundScreen insulation but also Kauf equivalent spec. Accoustic insulation. Effective flow resistivity (the key parameter for acoustic absorption) is approximatley 6000 RAYLS(Pa.s/m2). Despite the insulating materials having a flow resistivity of 12000-14000 RAYL on its front face, its horizontal orientation results in a lower flow resistivity (roughly halved) which is preferrable for velocity absorber deeper than ~400mm as it results in greater low frequency absorption. The frame is made of pine and Baltic birch ply and is reinforced with flatscreen mesh and 1” Dacron covering on the front face to prevent the glass fibre insulation hairs sticking out in the future. Cloth covering used is as acoustically transparent as I could find without custom ordering. Side covers facing walls are lower quality fabric used for the undersides of furniture and is breathable also. These are more effective that previous commercial bass traps I've owned, due to the depth of insulating they absorb deeper down the frequency range than most. The end result is cleaner and somewhat punchier bass and better clarity in all frequencies above the bass region. I'm moving to Brisbane in a week, so Melbourne buyers would have to get in quickly. The list price reflects this. $350 is below the material costs for these. The reason I'm selling is the high cost of shipping, plus I'll be moving into a rental up in Brisbane that may not have space for these. Due to their size a ute or van would likely be required for picking them up. Dimensions Depth is 580mm, length ~900mm and height around 1220mm each (~2.44m when stacked) Please see a model of the bass traps' approximate absorption coefficient curve below: Photos: 1
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