Using baffles to contain room reflections

[AllenB]

I am trying to find a device that will prevent a ceiling reflection. My main constraints are its height, and that it's broadband.

I have GD and comb filtering issues extending down into the bass. I need to manage 250Hz as much as possible, and preferrably everything above.

I have thought of hanging baffle curtains to reflect the sound back to the front wall where I have enough absorption to handle it, rather than using an 8" high absorber, or a narrowband panel absorber.

Can this be reliably done with low profile curtains? As an example in the diagram, where a single baffle 'A' could be used to deflect this span of reflections, so could the 'B' or 'C' options but would they restrict the lower working frequency?

[StigErik]

Curtains are acoustically transparent at 250 Hz, so this will not work. But if you build it with solid boards, it will become a kind of diffusor, though not very efficient. The sound will not reflect back, but rather be scattered around. Its better to build a deep and large absorber, or a proper QRD diffusor.

[speaker dave]

Heavy curtains or 2" fiberglass would do a good job at 250Hz.

Coefficient Chart

Here is a chart of absorption coefficients. I think you might also pick up a little advantage from the material being off the surface, so you might experiment with 1".

A multiplicity of shorter curtains should also work, as long as, from your listening point you see no bare ceiling around the reflection point. If the curtains are longer than the minimum then the bounce wave will be passing through multiple layers, increasing efficiency.

David S

[StigErik]

The point was to reflect the waves back, not to absorb them ... ? In that case, neither curtains or fiberglass will do the job. Only solid materials will work, but as a whole the original idea here is flawed in my opinion.

Its better to absorb or diffuse in the ceiling rather than trying to reflect back to the front wall.