Which is more important?

[Diffusion]

Which place for absorbtion is more important, the wall behind your monitors, or the wall behind you (in front of your monitors)???

[vintagetobes]

i would have to say bringing your speakers off the back wall then placing absorbtion on the first reflective surface, so the walls immediatly to the side of your monitors.

[pandamonk]

Behind you, and the first reflection points on side walls and ceiling. Absorbtion wont really do much behind the monitors. All(well most) of the sound comes out and goes straight or is reflected to the back of the room.

[LemonTree]

Originally Posted by Diffusion

Which place for absorbtion is more important, the wall behind your monitors, or the wall behind you (in front of your monitors)???

Are your monitors front or back ported?

[bpape]

Just to be clear, most of the mid and high frequencies do in fact act more like a ray and go pretty much in a straight line forward. However, lower mids and bass frequencies radiate as a sphere. So, absorbtion behind the speaker can in fact be VERY beneficial in helping to tame that rear wave and knock down the amplitude of the out of phase information off the front wall.

[Diffusion]

ok, so say I have limited auralex foam, where are the first places I should treat? I am mixing on BX5a's so I dont think bass freq's will be much of a problem...

[Rod Gervais]

Originally Posted by Diffusion

Which place for absorbtion is more important, the wall behind your monitors, or the wall behind you (in front of your monitors)???

Well - everything is equally important.

The wall behind your speakers can cause SBIR (Speaker Boundary Interference Response) which is a decrease in low frequency levels, the walls to your left and right and behind you - as well as the ceilings above you (if you have a hard finish floor) can contribute to flutter echo, comb filtering, and can also screw up your stereo imaging through early reflections.

Bass build-up will cause modal and non-modal issues including peaks, dips and nulls.

ALL of this make it impossible for you to accurately hear what is going on in your mix - which is why so many people spend hours running from their gear to their car - just to hear that the mix is muddy - too much bass, doesn't have any real stereo image, has a much too wide stereo image, etc., etc.

So the answer to the question is that they are all equally important - AND that you are mssing a whole lot if all you mention is all that you plan to install.

Sincerely,

Rod

[LemonTree]

Originally Posted by Diffusion

ok, so say I have limited auralex foam, where are the first places I should treat?

Put your auralex outside the studio door to wipe your feet on the way in

[chris-from-ky]

Originally Posted by Diffusion

ok, so say I have limited auralex foam, where are the first places I should treat? I am mixing on BX5a's so I dont think bass freq's will be much of a problem...

You mean you don't have any more of those wonderfully cheap moving blankets you could throw up on the walls.

Just joshin' ya, dude! I'd say side walls definitely. then ceiling, then front or back wall.

[Ethan Winer]

Folks,

> The wall behind your speakers can cause to SBIR <

Indeed, but just to be clear, to reduce SBIR the absorption material has to be very thick. The typical 1- and 2-inch foam I see people put on their front wall is not effective at all at 300 Hz and below where SBIR dominates. Though the concept Rod and Bryan explained is certainly valid.

--Ethan

[Rod Gervais]

Originally Posted by Ethan Winer

to reduce SBIR the absorption material has to be very thick. The typical 1- and 2-inch foam I see people put on their front wall is not effective at all at 300 Hz and below where SBIR dominates.

Ethan is 100% correct.......

Rod

[myfipie]

Originally Posted by Rod Gervais

Well - everything is equally important.

The wall behind your speakers can cause SBIR (Speaker Boundary Interference Response) which is a decrease in low frequency levels, the walls to your left and right and behind you - as well as the ceilings above you (if you have a hard finish floor) can contribute to flutter echo, comb filtering, and can also screw up your stereo imaging through early reflections.

Bass build-up will cause modal and non-modal issues including peaks, dips and nulls.

ALL of this make it impossible for you to accurately hear what is going on in your mix - which is why so many people spend hours running from their gear to their car - just to hear that the mix is muddy - too much bass, doesn't have any real stereo image, has a much too wide stereo image, etc., etc.

So the answer to the question is that they are all equally important - AND that you are mssing a whole lot if all you mention is all that you plan to install.

Sincerely,

Rod

Very well said Rod.. I get this question just about every hour on the phone and always think I am sounding like a used car salesman when telling them that the fronts and the back have to done..

Glenn

[SonicClang]

I think most people go with the LEDE (Live end dead end). The end of the control room you're listening at is the live end, and the back side of the control room is the dead end.

[Rod Gervais]

Originally Posted by SonicClang

I think most people go with the LEDE (Live end dead end). The end of the control room you're listening at is the live end, and the back side of the control room is the dead end.

Sonic,

Actually you have that backwards.

LEDE was a design concept that came from Chips Davis and Glenn E. Meeks, who persented a paper entitled History And Development Of The LEDE Control 1954 (B-5) Room Concept, in 1982.

Chips is generally credited for the LEDE design.

It's all about Reflection Control:

Live End/Dead End really took off in popularity in the 80s. These rooms were really the first real attempt to understand (and deal with) not only room sounds, but psychoacoustics as well.

With the front of the room dead (almost anechoic) and the rear end of the room live, Davis, and those who followed him, found a new, fresh approach to studio monitoring environments. The use of reflection control helped to create an environment with better stereo imaging. Using diffusion on the back wall helped to break up room echo, while still maintaining room energy.

Sincerely,

Rod

[Ethan Winer]

Rod,

> With the front of the room dead (almost anechoic) and the rear end of the room live, Davis, and those who followed him, found a new, fresh approach to studio monitoring environments. <

Yes, but over time studio designers realized you don't have to make the entire front half of the room dead. What matters most is placing absorption at the first reflection points.

--Ethan

[pandamonk]

Couldn't you put a mini broadband absorber behind each speaker, the size of the speaker and thick enough and with enough space behind to absorb all the problematic SBIR frequencies, instead of covering the whole back wall, or reflection point.

[pandamonk]

I just had an idea. A mixing booth sort of thing. Check the attached pic. with it, the further the desk is from the walls the lower the frequencies the booth will absorb. What you guys think(especially Ethan)?

[Ethan Winer]

Panda,

> the further the desk is from the walls the lower the frequencies the booth will absorb. <

Sure, but the bigger the "enclosure" you make, the more effort is needed to move it around etc. I think it would make more sense to just treat the walls and especially the corners.

--Ethan

[pandamonk]

I see your point, but won't the rigid fiberglass bit be quite lite? You could make it separate from the desk so that you don't have to move the whole thing in one stage. Surely this idea would mean that it absorbs much lower lows than bass traps in the corner(if your room is a bit bigger than it).

[Rod Gervais]

Originally Posted by Ethan Winer

Rod,

> With the front of the room dead (almost anechoic) and the rear end of the room live, Davis, and those who followed him, found a new, fresh approach to studio monitoring environments. <

Yes, but over time studio designers realized you don't have to make the entire front half of the room dead. What matters most is placing absorption at the first reflection points.

--Ethan

Ethan,

Understood - however my point was that Sonic was reversing the room - LEDE isn't a dead backwall with live front wall.

Although there are designs out there exactly like he described - they are not LEDE.

Sincerely,

Rod