Decay Times for Small Room?

Posted: Fri Apr 06, 2007 5:15 pm

Hello All,

[This was split off a previous post, see "Difficult Acoustic Topics" at http://www.recording.org/ftopict-41527.html.]

Here are my questions:

1. How important is it to have a relatively flat decay time across all frequencies?
2. Does a reduction in decay time, directly equal a reduction in room modal response at low frequencies? Or can you have a nice short decay at low frequencies (say 0.3 - 0.6 mS) and still have room mode responses that need to be tamed?

Everest seems to indicate that relatively flat decay times across all frequencies is the desired end goal. The idea I think, is that if the decay times are much different, then muddiness in the sound will appear at different frequencies, distorting the mix. Achieving this absorption would also seem to directly take care of the room modes, although it is difficult to achieve this absorption at low frequencies (below 125 Hz).

So let's say I treat my room with a lot of 4" type 703 absorbers, some on the walls and some over the corners. Then I add some tuned low frequency absorption to help out the lows. Due to their absorption properties and using the Sabine equation, I will likely end up with (calculated at least) T60 decay times that are relatively long at the lows, short at the mids (125-500Hz), and medium at the highs. Maybe 0.7 mS at the lows, 0.2 mS at the mids, and 0.35 mS at the highs. Definitely not flat.

Would this sound bad? Unnatural? Distorted?

The point here is, if indeed the room would sound bad, then it seems important to plan my absorber types such that they work together to get a flat decay time across all frequencies. That's the subject of this post: "Low Frequency Absorption Methods in Small Room?" at ????.

Thanks,

Kevin

Posted: Fri Apr 06, 2007 5:18 pm

Sorry, forgot the link for "Low Frequency Absorption Methods in Small Room?":

http://www.recording.org/ftopict-41594.html

Kevin

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