measure long reverberation times

[ordinateur]

Hey guys,

i wanted to measure reverberation time in a reverberation chamber with an expected rev. times from 10 sec to 2 sec frequency dependent. REW only got "good" RT60 data when I used 128k sweeps, a few times averaged (44,1kHz, 1 sweep was ca. 3 sec). Every other setting hat one or many 0 sec results. I guess it has sth. to with the cut of the impulse response - but maybe also not. Does anyone have an idea, why this is so, and maybe a proposition what my settings are missing to measure very long rev. times?

Best!

 

[Bernard]

Hey guys,

i wanted to measure reverberation time in a reverberation chamber with an expected rev. times from 10 sec to 2 sec frequency dependent. REW only got "good" RT60 data when I used 128k sweeps, a few times averaged (44,1kHz, 1 sweep was ca. 3 sec). Every other setting hat one or many 0 sec results. I guess it has sth. to with the cut of the impulse response - but maybe also not. Does anyone have an idea, why this is so, and maybe a proposition what my settings are missing to measure very long rev. times?

Best!

Hey guy,
If you think it has something to do with the impulse response cut, then look at the picture and try it.
Note that the computation time will be longer.
That's where my expertise ends.

 

[John Mulcahy]

Use longer sweeps (512k or longer) and keep more (or all) of the IR.

 

[ordinateur]

Hey guy,
If you think it has something to do with the impulse response cut, then look at the picture and try it.
Note that the computation time will be longer.
That's where my expertise ends.
View attachment 57319

Oh, that's to easy, sorry that I didn't check! Thank you so much already. But do you know, if I need to provide the truncate setting before measurement, if can I also do it after measurement, because maybe REW stored the whole thing somewhere?

 

[John Mulcahy]

It has to be set before measurement.

 

[ordinateur]

It has to be set before measurement.

Thank you!