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[sui-city]

Hi,

Fran, thank you so much for all the insights.

I just wish to ask where i could find a list of room ratios for room that are short and wide as opposed to longer and narrower.

Thanks in advance

[jimmyjazz]

The "goodness" of a set of room ratios isn't a function of the orientation of the mixing desk & monitor array.  When people talk about good or bad room ratios, they are almost always speaking exclusively of low frequency mode distribution.  In that sense, a room that is A x B X C is identical to one that is B x A x C.

It seems that there is a pretty strong consensus in the industry that placing the monitors on the short wall of a rectangular control room allows for a better mix/monitor function, because it puts the back wall farther from the engineer than if the room is oriented the other way.  If you are planning a rectangular control room where, for whatever reason, you feel you need to place your monitors on the long wall, then I think you are most likely going to be forced to add significant absorption on the opposite long wall; otherwise, the reflections from that wall (even if diffuse) will arrive at the mix position very shortly after the direct sound, and chaos will ensue.  It's certainly not an ideal mix environment.

Looking forward to the thoughts of fran, jay, and ethan, among others . . .

[Ethan Winer]

Jimmy,

> It seems that there is a pretty strong consensus in the industry that placing the monitors on the short wall of a rectangular control room allows for a better mix/monitor function, because it puts the back wall farther from the engineer than if the room is oriented the other way. <

Yes, proximity to the wall behind you is always a big problem. And it's not only industry consensus - it's also pretty easy to prove. In fact, I just happen to have this graph handy...

--Ethan

[L_Tofastrud]

"Room ratios"
Some numbers have been quoted as always giving beneficial modal distribution.  It all depends on the size of the room as one "room ratio" can work great with a 3 meter ceiling height it might not work as well with 5 meters.  We always do a series of modal calculations and simulations before we are happy.

Regards
Lars Tofastrud

[jfrigo]

I also generally prefer to shoot into the long dimension, having the speakers on the shorter dimension wall. However, in some cases, due to space constraints and a big, long 72, 80, or 96 input console, as a practical matter you have to orient the room the other way. It's not impossible to have a good sounding control room with this orientation, though it is more of a challenge. You need a certain amount of depth regardless of the orientation or you are going to be in trouble WRT the listening position (you don't want to be dead center) and reflections from the back wall if it's too close. With enough trapping of proper design, you can make it work, but I'd rather spend my time, money, and energy making a good room excellent than a mediocre room good.

[franman]

I have to say that we've completed succesful, good sounding rooms, in both orientations.... The dimensions are more important for LF Modal response than the orientation for sure. BUT the proximity to wall surfaces is always a concern.. As Ethan aptly illustrated, being too close to the rear wall can be a nightmare... but the same destructive early reflections can occur from being too close to the side walls... Pick your poison AND TREAT EARLY REFLECTIONS!!

[sui-city]

Thank you all for your suggestions and insights,

When treating the rear wall in an orientation such as this, would diffusion or absorption be best?

Thanks again

[jimmyjazz]

You're going to have to put significant absorption on that back wall unless it's at LEAST 7-8 feet from your listening position,and more ideally 10-11 feet back.  That early reflection, no matter how diffuse, will mess with your head.  (Literally!)

[franman]

agreed...

you might scatter a little 2D diffusion along the outside corners of the rear wall.... installed in corner traps?? this would move them a little farther away (round trip) that in the middle and allow you to trap the middle. The 2D units such as RPG Skylines and Omnifussors have a slightly more attentuated return as the energy scatter over a hemisphere as opposed to semi circle..

[Wes Lachot]

Hi folks. Great forum. It's been a couple of years since I've posted on any forums, so please forgive me if I press the wrong button.

I was reading along and this thread got me to thinking:

  Fran wrote on Fri, 15 September 2006 15:07

Quote:

BUT the proximity to wall surfaces is always a concern.. As Ethan aptly illustrated, being too close to the rear wall can be a nightmare... but the same destructive early reflections can occur from being too close to the side walls...

Fair enough. But limiting the discussion for a moment to low frequency cancellations, wouldn't the destructive interference from the left wall cancel out the destructive interference from the right wall, assuming a symmetrical room and listening position, and low frequency instruments panned to the center of the mix? A case of self destructive interference, so to speak?

Food for thought--like I said, this thread got me to thinking...

[franman]

Wes,

To equal short reflections off side walls will just cause a deeper comb filter... the distance has to be long enough to creat the low frequency comb filters, which might be a factor in Ethans graph?? Have to see the impulse response... With regards to LF cancellations caused by Speaker Boundary Interference, having two (equal) side wall Interference situations will, once again, all things being equal, just cause a deeper cancellation for LF... the frequencies being affected are based on the difference in the distance from the source to the listener and the source-reflection point-listener... with the SBI it's typically a 1/4 wavelength issue from the port or woofer on the speaker to the boundary... make sense??

[Wes Lachot]

Fran,

Yes, that makes perfect sense.
Thanks.

[Ethan Winer]

Hey Wes, great to see you here!

[garret]

jimmyjazz wrote on Sat, 16 September 2006 10:28

You're going to have to put significant absorption on that back wall unless it's at LEAST 7-8 feet from your listening position,and more ideally 10-11 feet back.  That early reflection, no matter how diffuse, will mess with your head.  (Literally!)

I can attest to this... My home "studio" (I'm being charitable here in calling it that) is the old side porch of my house.  The room is 20 ft by 8 ft, with one long brick wall, and the other three walls of wood trim and large windows.

Setting up the long way is troubling, because the reflections are so out of balance (brick on one side, windows on the other).

The only workable solution I've found so far is to set up facing the long brick wall, and cover the back wall (long wall of windows) with 4" rigid fiberglass.  So I basically have a dead wall behind me, and _lots_ of bass trapping.  It works, er, sort of!  At least well enough to get by until I build something better in the basement.

-Garret

[Wes Lachot]

Garrett,

Since you have a long row of windows on the long wall behind you, much of the bass energy hitting the rear wall is going outside and not causing interference with the direct sound. This is a good thing, as long as the neighbors don't mind. If that rear wall was very solid you probably wouldn't be able to stand the bass reflections. A very close, solid back wall gives the low frequencies a ghostlike, ethereal quality that is extremely hard to judge.