Online Control Room /Studio Room frequency calculator

[TerryG]

Here's a fantastic online calculator for everything you wanted to know about rectangular room tuning. It shows modes, recommended absorbtion sabins on all surfaces for best RT60, etc. You'll want this link in your favorites.
Check your existing room and see where you can make improvements, or pre-screen the possibilities of what you might want to build. Imperial US or Metric.

Click one of the "compute" buttons using the default measurements and watch it unfold.
Then, insert your own measurements, take notes, and compare:


Bob Gold's Room Modes (http://www.bobgolds.com/Mode/RoomModes.htm)

Click on the "Explanations and References" at the bottom of the page for more info.

You'll discover the default measurements provide a very good spec.
I've managed to come up with only a few dimensions that have a better graph and Bonello curve for the spaces I'm designing. Very cool tool.

[Animus]

hmmmm cool. My studio is in a finished attic so it has a vaulted type ceiling. I wonder how I would calculate that.

[TerryG]

hmmmm cool. My studio is in a finished attic so it has a vaulted type ceiling. I wonder how I would calculate that.

My rooms will be vaulted as well...

What I've done is to calculate dimensions in three ways:
Using the lowest wall height, the highest, and calculating what the median would be based on whether the slope is continual or tops out before reaching the other side of the room.

These three graphs will give you a decent range to analyze what your overall situation is. Sonically, the vault angle alters reflections, but the volume of the room is still relative to some parameters of the calculator.
It would be cool to find some mathematician/Excel expert who could add a variable vault formula to these equations.

[Animus]

Cool let me know what you figure out.

Incidently, have you taken a look at ARC or that KRK ERGO?

[TerryG]

Cool let me know what you figure out.

Incidently, have you taken a look at ARC or that KRK ERGO?

I'll familiarize myself with those...

I've read about the older JBL Smaart, but never seen it in action.

And, there's an older program from the early 90's called MLSSA, known as "Melissa", that Robert Walker from the BBC refers to in his Controlled Image Design (CID) theory of creating minimal 15mS or less surface reflection paths for the ideal console listening position for any specific stereo speaker placement. I'd love to find that, or something with a similar capability. I've found some BBC Research papers online with dimensions and measured results for a couple designs... very cool stuff (to me).
I've converted the metric dimensions to US and I'm considering a 3/4 scale design since my shell space is smaller.
My in-wall speakers would be about 6' apart in an equilateral triangle instead of the 8' used in the BBC test room. And, the charting from the specs using Bob Gold's room Modes look very good.

Here are the primary CID papers:

http://www.bbc.co.uk/rd/pubs/reports/1995-03.pdf

http://downloads.bbc.co.uk/rd/pubs/reports/1995-04.pdf

Here's a link to a wealth of BBC Research information from several years, targeting 1995 to start:
http://www.bbc.co.uk/rd/pubs/reports/1990s/reports1995.shtml

Not much in the way of new thinking has happened in control rooms since.

[Andrew J]

Another useful tool can be found at www.realtraps.com (http://www.realtraps.com/modecalc.htm) (it's a windows exe). It's worth reading the help.

I don't have vaulted ceilings, but I do have a rectangular room where each corner is cut-off so that I end up with something a bit octagonal. Probably doesn't improve the axial modes, and might even make the tangential and oblique modes worse. Not sure really!

-Andrew

[TerryG]

Another useful tool can be found at www.realtraps.com (http://www.realtraps.com/modecalc.htm) (it's a windows exe). It's worth reading the help.

I don't have vaulted ceilings, but I do have a rectangular room where each corner is cut-off so that I end up with something a bit octagonal. Probably doesn't improve the axial modes, and might even make the tangential and oblique modes worse. Not sure really!

-Andrew
It can be like navigating a minefield trying to sort all the theories. The Bob Gold calculator is a great reference for parallel walls. But, other common theories say that avoiding parallel walls is the best thing to do, while others recommend maintaining symmetry with angles overall.
Andrew, are you in a situation with your corners that would benefit from making them quarter-round columns for dispersion, perhaps perforated to absorb some of what would otherwise be reflected? If so, there are formulas for designing these to target certain frequencies.

[Andrew J]

Andrew, are you in a situation with your corners that would benefit from making them quarter-round columns for dispersion, perhaps perforated to absorb some of what would otherwise be reflected? If so, there are formulas for designing these to target certain frequencies.

No, it's a hundred-year old house and the corners are built that way - two of them are external and have windows in them and the two internal ones have little triangular cupboards in them. I'll probably just put some gobos in front of them.

[Animus]

Another useful tool can be found at www.realtraps.com (http://www.realtraps.com/modecalc.htm) (it's a windows exe). It's worth reading the help.

I don't have vaulted ceilings, but I do have a rectangular room where each corner is cut-off so that I end up with something a bit octagonal. Probably doesn't improve the axial modes, and might even make the tangential and oblique modes worse. Not sure really!

-Andrew


Just stick some bass traps in those cutoff corners and see what it does. Don't go with Real Traps. Try GIK Acoustics. Much cheaper, not as cosmeticly pleasing, but gets the job down. I got 8 of their traps and heard a distinct improvement.

[Andrew J]

Stacy, you've got no idea how important aesthetics are to my wife! As far as sourcing the treatment, there are a number of Aussie based companies I'm considering - but thanks to the pointer to GIK, I haven't come across them before.

[D]

I fly out of Hobart all the time in my twin engine Beechcraft Baron 58.

[Andrew J]

I fly out of Hobart all the time in my twin engine Beechcraft Baron 58.

Can you fit any acoustic panels on board? :D