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22nd December 2010
#1
Gear Nut

How to work out room dimension for Mode Calculator when you have a sloped roof.

Hello,

I am starting to look at Room Mode Calculations and I wonder, my control room will be

4470mm wide
6400mm length
and the height is angledfrom side to side so as I sit at the mic position, to my left the wall is approx 3300 and on my left the wall rises to approximately 4500.

THese heights are estimates at this stage, but pretty close.

So, I am not sufre what height to enter in teh room mode calculator.

I am using John brandts calculator on his website.

Regards

Vic
22nd December 2010
#2
Lives for gear

is this an existing space, or are you using the calculator to determine dimensions to be built?
22nd December 2010
#3
Registered User

How do you use a calculator based upon an ideal rectangular space to determine the behavior in an irregular polygon?

You don't.
You measure.
22nd December 2010
#4
Gear Nut

Hi,

Thanks for the replies.

The room is partially built. The only dimesions I could really change would be the length of the room, which it would be possible for me to shorten.

But, so I guess the Room Mode Caclulator isn't appropriate then. Is it possible to do some sort of calculation or will I have to rely on testing in the room once it is up to that acoustic treatment stage ?

Thanks again.

Vic
23rd December 2010
#5
Lives for gear

So i have thought about this exact question quite a few times. It makes sense what SAC says... it should be pretty impossible to calculate the outcome.

But maybe one can say what could be expected by a cacave ceiling?
The concave ceiling would probably be bad for reflection since it would reflect ALL reflections towards the middle of the room.
But what about modal issues? Wouldnt a concave ceiling be beneficial for modes, since there is not specific roomheight?
23rd December 2010
#6
Lives for gear

Circular walls or concave ceilings would just make the room very uneven in response to modal activity as you move about it.

Neil
23rd December 2010
#7
Lives for gear

I read the original post again.

Am I right that your ceiling will slope from left to right? I would worry more about that than modal predictions.

MHOA states that an average of the two heights can be used to quote un "ballpark".... though it will be a very rough ballpark. Think Metrodome rough.
23rd December 2010
#8
Lives for gear

Quote:
Originally Posted by nixoblivion
Wouldnt a concave ceiling be beneficial for modes, since there is not specific roomheight?
I'm building a room in the attic of an A frame house... no even ceiling at all. I'll let you know. My gut tells me that there will be no pronounced axial height or width mode, rather a lot more oblique, and their overlap and locations could make this an utter failure, or a rousing success. Stay tuned, the thread is in my sig. line.
23rd December 2010
#9
Gear Nut

Hi,

Thanks again,

As I am sitting in the mix chair, the ceiling slopes from my right being the lowest part to my left being the highest part.

So do you think this sloped roof is putting me in a worse position for when it comeds time for acoustic treatment?

I'll have a look at your studio build thread later today as I have one more day of a builder here who is helping with framing and he is about to arrive.

Regards

Vic
23rd December 2010
#10
Lives for gear

left right symmetry is very important... particularly in the front half of the room.

this may be a case where breaking that "rule" of having the speakers firing down the length of the room is "always" better.

haven't done a conversion, but if I'm not mistaken, what you are currently considering your width is approx. 14' or so? That's not a bad length. WHat room model are you using? RFZ, non-environment,...? I would center your rig on the right wall... but as always, measuring the response is going to be the way to go.
18th September 2015
#11
Here for the gear

Viccy, yo can measure a roof pitch here
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