How much Absorbtion?

Prickstein · 18th February 2005

Start decking out the garage this weekend as a space to track and mix in. Got my rigid Fibreglass and fabric ready.
Just wanted to check how much of the room should be absorbtion and how much diffusion.
The room is roughly 6m x 5m, Hardwood timber floors and I'm going to deaden the cieling which is 2.4m high. Two big windows at the front of the room.
For the walls, are we talking 60% dead 40% live?
My thoughts were to deaden the back wall completely, deaden around the front windows and alternating strips of live, soft on the side walls.
Any suggestions?

Ethan Winer · 18th February 2005

Stein,

> how much of the room should be absorbtion and how much diffusion. <

Angelo's advice from Bruce is right on, though that pertains more to picking good room dimensions and shape, rather than what percent absorption you asked about.

One very rough guideline is to treat about 30 percent of all the surfaces combined. Here's how I approach this:

Start by treating as many corners as possible with bass traps. Some bass traps also absorb mid and high frequencies, so that might or might not add to the 30 percent total.

Next is to treat the first reflection points on the side walls and ceiling with absorption. Placement for those panels is very specific, and is generally a small part of the total.

Next is to consider all parallel opposing surfaces. If the floor and ceiling are both reflective, you'll definitely need to treat the ceiling. A lot of studio designers use a cloud that covers much of the ceiling, but leaves a small (2 to 3 feet) border around the edges reflective.

> My thoughts were to deaden the back wall completely, deaden around the front windows and alternating strips of live, soft on the side walls. <

I like stripes, and a checkerboard pattern is good too. I don't think you need to deaden the entire front or back wall. The back wall could be treated just around the center portion. The front can be treated more to the outside, closer to the speakers.

As for diffusion, good diffusors are useful, but the cheap ones I've heard sound worse than a bare wall. Further, your room is a bit small for diffusion. I'd start with absorption and then consider adding diffusion later only if you're still not satisfied.

--Ethan

Prickstein · 19th February 2005

Thanks heaps for the tips guys!
Couldn't think of two more respectable names to take advice from.

dim light · 19th February 2005

Some of the bad can be good to make a sonic imprint of the actual voice. If we all should record in perfect landscape there would not be a sonic imprint.

Let's not forget that.

18th February 2005	#1
Prickstein Gear addict Join Date: Aug 2004 Location: Gold Coast, Australia Posts: 462 Thread Starter	How much Absorbtion? Start decking out the garage this weekend as a space to track and mix in. Got my rigid Fibreglass and fabric ready. Just wanted to check how much of the room should be absorbtion and how much diffusion. The room is roughly 6m x 5m, Hardwood timber floors and I'm going to deaden the cieling which is 2.4m high. Two big windows at the front of the room. For the walls, are we talking 60% dead 40% live? My thoughts were to deaden the back wall completely, deaden around the front windows and alternating strips of live, soft on the side walls. Any suggestions? __________________ Every day I learn something new (with a little help from my slutz), and that keeps me going.

18th February 2005	#2
Ethan Winer Gear Guru Join Date: Oct 2002 Location: New Milford, CT, USA Posts: 12,050	Re: How much Absorbtion? Stein, > how much of the room should be absorbtion and how much diffusion. < Angelo's advice from Bruce is right on, though that pertains more to picking good room dimensions and shape, rather than what percent absorption you asked about. One very rough guideline is to treat about 30 percent of all the surfaces combined. Here's how I approach this: Start by treating as many corners as possible with bass traps. Some bass traps also absorb mid and high frequencies, so that might or might not add to the 30 percent total. Next is to treat the first reflection points on the side walls and ceiling with absorption. Placement for those panels is very specific, and is generally a small part of the total. Next is to consider all parallel opposing surfaces. If the floor and ceiling are both reflective, you'll definitely need to treat the ceiling. A lot of studio designers use a cloud that covers much of the ceiling, but leaves a small (2 to 3 feet) border around the edges reflective. > My thoughts were to deaden the back wall completely, deaden around the front windows and alternating strips of live, soft on the side walls. < I like stripes, and a checkerboard pattern is good too. I don't think you need to deaden the entire front or back wall. The back wall could be treated just around the center portion. The front can be treated more to the outside, closer to the speakers. As for diffusion, good diffusors are useful, but the cheap ones I've heard sound worse than a bare wall. Further, your room is a bit small for diffusion. I'd start with absorption and then consider adding diffusion later only if you're still not satisfied. --Ethan __________________ Ethan's audio book is coming!

19th February 2005	#4
dim light Lives for gear Join Date: Dec 2003 Location: China Posts: 2,336	Some of the bad can be good to make a sonic imprint of the actual voice. If we all should record in perfect landscape there would not be a sonic imprint. Let's not forget that. __________________ Moderators you can't kill my art!

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