# Decay time - what is the "Holy Grail"



## hjones4841 (Jan 21, 2009)

I know that the first priority of room acoustic correction is to eliminate obvious ringing and FR errors. But, how can the optimum decay time for a given room be calculated, or is the answer "it depends"? The room is a dedicated 7.1 HT and is used exclusively for video/movies. Thanks.


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## bpape (Sep 14, 2006)

Well, it kind of depends on the size of the space. You can kind of use RT30 or RT60 calculations similar to a control room in a studio but you don't want it quite that dead. RT60 really isn't accurate for small space acoustics but it'll give you a general idea.

Try this link

http://www.bobgolds.com/Mode/RoomModes.htm

After you run it with your dimensions, scroll down lower right and there are a couple of different suggestions for different applications as well as some notes abouthow the room relates to known 'good ratios' and whether the room passes some general rules of thumb.

My son is actually working on something similar as a school project. Once he gets it done, I'll post a link. 

Bryan


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