Membrane absorber advantages

[Vaughan Odendaa]

Hi there,

The traps made by Realtraps and GIK acoustics all have membranes that improve low frequency absorption. But the panels made by Readyacoustics have no membrane as far as I know.

Is there a substantial difference in absorption with and without the membrane (for a given thickness) ? Little benefit ? Thoughts would be much appreciated.

--Regards,

 

[bpape]

Membranes provide a 'hump' in absorbtion over a specific frequency range. In the case of our products, at a slight reduction in the high frequency absorbtion range - but not enough that it can't still be used as a reflection absorber.

The center frequency of the 'hump' in this type of damped membrane arrangement is determined mostly by the rigidity of the absorbtive material damping it and the cavity behind the membrane.

In the case of a more conventional undamped membrane, the ONLY absorbtion provided is the range that the membrane covers. There is little to no HF absorbtion. It's range is determined by the mass of the membrane and the depth of the cavity behind. In this type of absorber, it is critical to have an air-tight seal or performance efficiency will suffer.

Bryan

 

[Vaughan Odendaa]

I thought that besides reflecting back a portion of high frequency reflections, membranes would also increase low end absorption.

Is this not the case ? Btw, do you have any idea if the panels made by Auralex have membranes ? Thanks !

--Regards,

 

[bpape]

Looking at the specs, I'd say the Auralex do not.

There is an increase in bass absorbtion - in the range where the hump is. The rest of the bass range is very similar to a non-membrane type absorber of the same thickness and absorbtive density.

The general use for a typical undamped membrane absorber is to tune very deep where typical broadband absorbtion would just be too thick to be practical. IN general, these are used only in larger rooms as broadband is typically a better solution in smaller to moderate sized rooms where there just isn't the luxury of specific treatments for each range.

Bryan

 

[Vaughan Odendaa]

Thanks for your input !

--Regards,