# 1" ceiling absorbers



## patchesj (Jun 17, 2009)

My ceiling is under 8' and I want to get some absorbers on the ceiling to cover my first reflection points. Is 1" an acceptable thickness? Do I really need to go to 2"? What would the best material be for 1" absorbers?

Thanks


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## bpape (Sep 14, 2006)

1" isn't going to do a lot. Certainly will miss most of the male voice range and lower. 2" with a small gap would be better.

Also, under 8', you'll have problems in the midbass from height modes. A thick panel over your seating position would be advisable.

Bryan


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## patchesj (Jun 17, 2009)

Are the absorber thickness recommendations based on wave length? I was thinking about building a large stary sky type thing for the ceiling to cover the reflection points and extend to over the first row seating (primary spot for music listening).


I also have an odd 6k ringing that I picked up after adding side wall first reflection panels (2" rock wool). Not audible, but shows up on RT60.


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## bpape (Sep 14, 2006)

Most likely, the ringing was being masked before somewhat.

For reflection duties, you can't look at it as straight line wavelengths vs typical 1/4 wavelength thicknesses. Reflections are more random angle more similar to how treatments are measured in a lab. 

Bryan


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## patchesj (Jun 17, 2009)

Ah, that makes sense I think... You could have the sound entering almost up to 90 degrees to the face, and exiting at the same angle. Or at a minimum it would enter and exit head on.


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