# calculating Reverberation Time, REW



## devincen (May 2, 2013)

Hi,

I'm new to REW and I would like to calculate some reverberation times. I recorded three impulse responses in different rooms and hoped, by using REW that I could calculate the reverberation times. Has anyone any idea, how to do so?

Thank you very much!


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## AudiocRaver (Jun 6, 2012)

On the main REW screen, there is an "RT60" button above the graph area. Give it a click. There is also an "RT60" button on the Overlays screen.


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## devincen (May 2, 2013)

I noticed, but when I go in the overlays screen and click on RT60. Do have to do make the difference between the two ends or, how do I calculate the RT then? If I want the "overall" RT, do I have to chose Topt?
Thank you!


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## JohnM (Apr 11, 2006)

You'll find explanations of the RT60 traces in the REW help and here. To look in more detail at aspects of the decay use the Filtered IR graph, the traces on that graph are explained here.


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## AudiocRaver (Jun 6, 2012)

devincen said:


> I noticed, but when I go in the overlays screen and click on RT60. Do have to do make the difference between the two ends or, how do I calculate the RT then? If I want the "overall" RT, do I have to chose Topt?
> Thank you!


Ah, you want an overall broadband RT60 number. JohnM would have to add a calculation for that.

JohnM: How hard would that be? How useful would it be?


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## devincen (May 2, 2013)

I'm just looking for a way to calculate the reverberation time of a room. I recorded some impulse responses from several rooms and I thought by running them through REW I would get some answers. Can I do that with REW or are there other (rather simple) ways to do so?
Thank you!


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## JohnM (Apr 11, 2006)

Yes, REW does that. Just import the impulse responses (File -> Import Impulse Response) and look at the graphs. Everything is calculated for you, I'm not sure how it could get any simpler.


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## AudiocRaver (Jun 6, 2012)

JohnM: I believe devincen is looking for a way to get to a broadband RT60 value, which REW does not provide, correct?


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## JohnM (Apr 11, 2006)

AudiocRaver said:


> JohnM: I believe devincen is looking for a way to get to a broadband RT60 value


That is what the Filtered IR plot shows with no filter.


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## stevekale (Jan 19, 2013)

You may find this article helpful in thinking about what measurements you might like to generate:

http://www.acousticfrontiers.com/st...0681100537/acoustic_measurement_standards.pdf


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## devincen (May 2, 2013)

Thanks for your response. Maybe I have to be more clear about what I want to do. I'm writing a (rather small) thesis about the effect of room acoustics on music performances. In this context I'd like to do a small experiment: I'd like to perform the same music in several rooms with each a different acoustic. Then I'd like to compare the different recordings and look for significant differences between them. Reverberation time seems to me one of the important factors that can influence the performance. That's the reason that I want to measure and calculate it.
This is only a small experiment, so in this case I haven't the intention to go in depth and measure all the aspects that could influence the performance.

Suggestions and tips are welcome, thanks a lot!


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## AudiocRaver (Jun 6, 2012)

JohnM said:


> That is what the Filtered IR plot shows with no filter.


Of course! Excellent. Thanks, John.


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## janick (Mar 10, 2011)

I'm trying to calculate my room reverberation time. I saw a comment on AVS forum but am not having luck on how to calculate. The comment was:

"I would try to reduce the reverberation time in relation to the listening position. You'll have to calculate this or pay someone to do it. If you are good with math, then you can write a spreadsheet or program to help you calculate the room. I would aim for 400 ms. The calculation will determine how much "stuff" to put on the walls."

Can REW give me the "ms" number? Attached is my .mdat fime


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## JohnM (Apr 11, 2006)

Just click on the button for the "RT60" graph, the Topt trace shows you the RT60 values in each frequency band.


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## RossoDiamante (Aug 12, 2013)

This is an awesome reference. But it is clearly for 2 channel (stereo) listening rooms and explicitly assumes that this is different than for studio or home theater configurations.

Is there a similar reference for home theater configurations?


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