Room dimensions?

djc

djc

Why so serious?
I'm completely rebuilding my garage walls, which gives me an opportunity to reconfigure my little recording room out there. Right now it is 9'-7" long x 6'-10" wide with 8'-4 1/2" ceiling from the floor. The door is in the middle of one of the short walls, and I have my stuff on the other end, with a small window in one of the long walls for an A/C unit. I would like to make it a little bigger. I read somewhere about an optimal height, width, length ratio for a mixing room, but can't remember what it was. I do recording on my own going direct with guitar and bass, synth drums. The only thing I record live is vocals. Any suggestions on changing size?
 
You can do lots, depends mostly
on your budget and timeframe.

Can you make it, say 21x43x19?
That would let you do great drums.

A really cool things to do are:

1) have non-parallel walls and ceiling/floor.
Helps a lot with standing waves.

2) have a freestanding room inside your room,
to control sound escaping out, and leaking in.

Avoid having any dimention be a multiple
of any other. A room that is 12x16x8 will be terrible.
 
djc said:
... I read somewhere about an optimal height, width, length ratio for a mixing room, but can't remember what it was. ...
Click to expand...
I asked that question once too, but I don't remember the answer. I think it's like 1.0 - 1.6 - 1.2 LWH
The thing is, with control room geometry and non-parallel walls, the "optimal" dimensions kind of go out the door.

Like fishtop said, avoid parallel walls and dimensions that are multiples of each other.
 
I have a 17' x 20' garage, but my wife won't let me take all of it. I'll do some thinking about the non-parallel walls. I don't need much room because I don't have real drums, and don't intend to. I've decided to go the real guitars synth drums route. It's just a hobby, and I'm too old to be a rock star. But I do want as good a mixing room as I can build. Thanks for the input guys.
 
Your existing room ratios aren't bad at all, for that small an area.

There are several so-called "golden ratios" for rooms, one of the most common is 1:1.6:2.33 - an example of this would be a room with 10 foot ceilings, that is 16 x 23.3 feet. These ratios don't matter whether the ceiling height is the small or large dimension, only the ratios make much difference. The BBC use this in some of their vocal booths, it's referred to as "standing the room on end" -

With that small a room, there isn't really enough room to splay walls unless the adjoining areas can also have splayed walls. This will mean more wall treatment is necessary to combat the flutter echo that comes with parallel walls.

"The thing is, with control room geometry and non-parallel walls, the "optimal" dimensions kind of go out the door. " -

Not really, Michael - granted, they don't matter as MUCH, but the room will still have a more even sound signature if the AVERAGE LWH values are in good ratios to each other.

The non-parallel walls get rid of flutter echo, and they also "spread out" the modal resonances so they are much less noticeable, but if the average ratios of the room are allowed to be even multiples of each other the room still will have a less smooth/neutral characteristic sound that it imparts to the music.

You can still find ideal ratios of non-rectangular rooms with a spreadsheet designed for parallel walls - you just need to use AVERAGE values for each dimension, then double-check with minimum and maximum values for each dimension to make sure there aren't any surprises (like narrowest long dimension vs. widest width dimension being same )

If you can, it helps a lot to make a control room at least large enough so that you can keep the speakers at least a couple of feet away from walls and still have your head several feet from the rear wall... Steve
 
Thanks for that explaination KnightFly.

So if I understand correctly, to calculate the average of meanest modes, you use the average, the mean and the mode? :confused: :p :p


A little research and I found this:

the Optimum Favorable Rectangular Room Proportions. These dimensional ratios result in the least number of repeating room resonances, minimizing both harmonic buildup and comb filtering.



per M. Louden
1st 1.00 1.9 1.4
2nd 1.00 1.9 1.3
3rd 1.00 1.5 2.1
4th 1.00 1.5 2.2
5th 1.00 1.2 1.5
6th 1.00 1.4 2.1

(How to: Plan your room with inside finished heights, widths and lengths, which are proportional to the highest "grade" of ratio possible. For example; if your space allows for the 2nd ratio, due to a finished width limitation of 13 feet, your length is 19 feet, and your height is 10 feet...
 
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Michael, those are some of the so-called "GR's" - Sepmeyer published some others, one of which was the one I listed.

Interestingly enough, my axial mode spreadsheet shows some minor improvements possible to almost every one of the so-called "Golden Ratios" as far as more even distribution - I'm attributing it to the fact that those were derived with pencil, paper, and possibly slide rule. I know I would get tired of endless "what-if's" without being able to just change one cell of a spreadsheet...

When you start splaying walls and sloping ceilings, the bad news is you make things harder to calculate (duh) - the good news is it's not as noticeable if you get it wrong.

Still, if you want the best sound you can get it's better if you take the average of all 3 dimensions of the room to use for axial mode calculations - then, more as a check than anything (since the splayed walls buys you some lattitude) I would check min and max of all 3 dimensions in all 6 combinations (3!) , just to make sure that a longer dimension's MINIMUM length doesn't coincide with a shorter dimension's MAXIMUM length.

If there is a computer program available that will do all this for you, I'm not aware of it - but then, I can't even afford to CLICK on a site that might offer such a tool, any more than I can afford 5 Dun's for surround, along with all the goodies that would imply - this is just my way of ensuring that if the room WERE to be rectangular, there STILL would be no problems caused by axial modes.

That's the mindset I'm using when (slowly) designing the rooms for my 40x50 facility, along with the idea that If I wanted to I could put a bullet trap at one end and practice with a .44 mag at 2 am and not disturb the neighbors (If I "shoot" for that goal, I should be able to thrash a set of acoustic drums to death without worrying about the outside world at all, ever.)

Did I ever get around to answering your question? Sometimes I get so caught up in this stuff I forget where I started and which direction I was originally headed... Steve
 
My question was a parody. I was just having fun.
Guess it wasn't that funny. :(
It sure would be nice (Steve) if someone (Steve) would modify their spreadsheet to account for splayed walls and sloped ceilings. :D
Not that it makes much difference to me, my framing is now complete except for the rear control room wall.

I did run the modes for all of my rooms, using the average dimensions and your spreadsheet, but that was way back when. I'd have to go look up the results, because its been so long ago, I don't remember.
 
Kinda thought you might be "jist funnin'", and prob'ly woulda been sure if I hadn't just got off 12-hour graveyard shifts :=( -
Maybe I should send you a copy of my shift schedule, so you could know when "subtle " works and when it's best to use the "John Henry" approach :=) (As in, "Hey, Dumb-Ass, I'm jokin' here)

As to the Spreadsheet - Much "sheetier" people than I have tried what you request, and I've still not seen one - soooo, I'm instead feverishly working on a cad program that estimates materials, hacks into Bill Gates' account, calls the necessary local contractors and automatically builds a studio on OPM (Other Pricks' Money) -

If I'm successful (REALLY successful) you'll not hear from me for extended periods of time, 'cause I'll be busy making noise, recording same, and fondling faders til I'm passed out from ecstacy (the feeling, not the drug) -

If I'm only PARTLY successful, You'll not hear from me for extended periods of time, 'cause I'm being careful not to bend over and pick up the soap, 'cause I only get one phone call a week and no internet access, and 'cause I'm trying to figure out whose "bitch" I need to become for the least amount of pain... :=)

All seriousness re-engaged, though, I guess it wouldn't take that much to set up more cells on my ancient "Roomtune" sheet so that it asked for min and max of each dimension (assumption of straight wall segments, not curves, sorry) then calc's average and charts that (like it does now) , and finally looks at all the combo's of min and max and pops up a flag if they coincide, or come closer than 4-5 hZ -

Or, I could just wait, and someone at Studiotips.com will save me the trouble, like they did with ModesV2.xls - I'm really glad I found that site BEFORE I started on a version that figured Tangential and Oblique modes - one of the FEW times my timing has been better than "wish I'd a"... Steve
 
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