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R/E/P => R/E/P Archives => Budget? Budget? We Don't Got No Steekin' Budjet => Topic started by: Asagaai on March 31, 2006, 07:15:28 PM

Title: Helmholtz Resonators/Hebble Block Walls
Post by: Asagaai on March 31, 2006, 07:15:28 PM
Hi all.

I have a small studio-tracking room 6.5 metres by 4.5 metres, control room 6.5 metres by 3.5 metres.

I need to build end wall in end of control room, and am going to build it out of hebble blocks (aerated concrete).  This material is like aero chocolate-easy to cut with diamond circular saw, but is fiddly to work with.  

Came to me that where the 2 blocks join, I will cut various widths off the join of both blocks to get a gap (neck).  Then as the neck moves into the 2 blocks, some 2 cm in I will cut out cavities of various dimensions (in rectangles/squares)in effect fabricating helmholtz resonators.  Because the sizes will vary the frequency absorption will vary as well.

I then intend painting the whole hebble wall surface, but leaving the neck and cavities unpainted.  Hebble block is incredibly absorbent, so the question is whether there will be much resonance.  However, I think that the cavities will be useful to absorb sizeable sabin counts across the frequency spectrum.

Does anybody have any acoustic theory that would indicate this is a waste of time, or worse, be counter productive to sabin absorption/creation of diffuse resonance?  Has anyone thought of this, done this before?

Much appreciated

Gavin Jensen
Newcastle OZ
Land of best beaches/babes
Title: Re: Helmholtz Resonators/Hebble Block Walls
Post by: Fibes on March 31, 2006, 07:48:41 PM
FWIW I did a room design with aerated concrete and it didn't really thrill me. It's easy to rout and work but very difficult to install without having to go with a finish over it. It looks sloppy real easy and to be honest doesn't have much mass so separation is not great. Personally i would think building stuff to mount to the A.C. would give you better results.

BTW it's Hebel for those of you looking at googling it.

Are they still in business? I know Ytong bought them and several plants shut down.
Title: Re: Helmholtz Resonators/Hebble Block Walls
Post by: Asagaai on March 31, 2006, 07:56:29 PM
Fibes, although it does not have much mass, I have achieved great results for separation.  The reason being it has aerated pockets throughout which isolate sound waves.  I have used this as the main wall between tracking and control room and no-and I mean-no sound gets through.

I agree that it can look a little messy-especially if you laid it like me.  But with tracking room I got it professionally rendered with cement-looks A1.

In the control, I left it rough, but painted it white, and I like the look of it rough, reminds me of African bungalow in scrub, and the rough surface also has acoustic benefits.

In Oz Hebel is still much around-very used now in townhouses-seperation walls-because acoustic isolation much better than double stud/brick walls.

But, anyone got any views on the helmholtz idea?


Gavin Jensen