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R/E/P => R/E/P Archives => Acoustics in Motion => Topic started by: PieterS on October 02, 2006, 07:13:51 am

Title: Choose between flattest response or room volume?
Post by: PieterS on October 02, 2006, 07:13:51 am
Hi Francis,

I am in the proces of building a room, primarily used for mastering. It is not a very large room, outer shell dimensions are (in metric, hope you don't mind):

5.66 x 4.61 x 2.67

For isolation purposes I want a 25 cm reserve, so max inner dimensions will be 5.16 x 4.11 x 2.3.

These dimensions will meet EBU, Bolt and Bonello recommendations.

To be sure I purchased RPG's Room Sizer software and this comes up with the following best dimensions for a flat response:

4.78 x 4.02 x 2.61

This also meets EBU, Bolt and Bonello recommendations and fits the RPG method ofcourse, but is 5 cubic meter smaller in volume.

My question is, should I choose the Room Sizer dimensions and live with a smaller room, or choose the largest room? Or am I too picky?

Hope it makes sense.
Title: Re: Choose between flattest response or room volume?
Post by: franman on October 02, 2006, 11:25:16 pm
understood.. I have to check the dims, but what method (other than room sizer) did you use to calculate your compliance with EBU and Bonello??
Title: Re: Choose between flattest response or room volume?
Post by: PieterS on October 03, 2006, 03:13:53 am
I used ModeWiz from John Griggs, found on the Acoustics Forum.

http://forum.studiotips.com/viewtopic.php?t=2256

You need an account there to access the file.
Title: Re: Choose between flattest response or room volume?
Post by: jimmyjazz on October 03, 2006, 08:56:18 am
I don't follow your math.  The room you came up with has an interior volume of 48.8 cubic meters, and the room RPG's software says is the "flattest", apparently within some constraints, has an interior volume of 50.2 cubic meters.  It's bigger than your design.  Assuming the 2nd room is in fact "flatter" than the 1st, it seems like a pretty easy choice to me, all other things being equal.
Title: Re: Choose between flattest response or room volume?
Post by: PieterS on October 03, 2006, 11:04:57 am
I am sorry, you are right, it should have the same height:

5.16 x 4.11 x 2.61

This equals 55 cubic meter.
Title: Re: Choose between flattest response or room volume?
Post by: jimmyjazz on October 03, 2006, 12:13:37 pm
1.  "25 cm reserve" sounds pretty arbitrary.  As you are no doubt discovering, the modal distribution of your room is fairly sensitive to your interior geometry.  I would try to nail down your wall construction details first before moving forward.  It's possible that "25 cm" is really "22.4 cm".  You'll want to know that up front.

2.  Over the small range you are talking about, I wouldn't concern myself with room volume.  "Flatness" is probably more important.  Other things come into play, too -- the distance from your mix position to the back wall, etc.
Title: Re: Choose between flattest response or room volume?
Post by: franman on October 03, 2006, 11:13:31 pm
.... what he said (thanks Jimmy!)... flatter response over volume in these sizes is the way to go. Also KNOW your final room size because sometimes that couple of CM (or an inch) can throw all the modal calcs out the window.
Title: Re: Choose between flattest response or room volume?
Post by: PieterS on October 04, 2006, 01:24:51 am
Thank you both!