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13th July 2009, 08:37 PM  #321  
diyAudio Member
Join Date: Nov 2004
Location: france

Quote:
Also very interesting to be read is the DRC manual If we consider windowing length for various softwares : for analysis soft : Acoustisoft R+D : LF 0.5 to 2 octave resolution, HF fixed time 2 to 10ms SMAART FPPO : 24 fixed points per octave ARTA dual gate : HF and LF 5 to 60ms SAT smoothFFT : near ERB ? PRAXYS FLEXwindow : HF short window (?), mid 20 to 100ms, and full window under 50Hz 7dBmore Room Capture multiwin : small time window 0.02 to 100ms, for correction soft in periods : Sigtech : 2 to 7 periods DRC : 3 to 20 or near ERB Acourate : 10 Audiolense : 5 Trinnov : 5 to 10 Here a comparison of some windowing length (periods vs frequency) 

13th July 2009, 08:41 PM  #322 
diyAudio Member
Join Date: Jul 2007
Location: Central Berlin, Germany

sidenote:
jlo, are you the man behind crossvolver? If so, I cannot get it to work (that is, routing of the inputs and output of my 8ch sound cards, virtual WAV input would be prefered anyway) and there is about zero info on the net. A thread here on DIYA on it would be nice.  Klaus 
13th July 2009, 08:51 PM  #323  
diyAudio Member
Join Date: Nov 2004
Location: france

Quote:


13th July 2009, 08:58 PM  #324  
diyAudio Member
Join Date: Nov 2004
Location: france

Quote:


13th July 2009, 09:18 PM  #325 
diyAudio Member
Join Date: Jul 2007
Location: Central Berlin, Germany

>> yes, just mail me
OK, thanks... I will summarize what my "core problems" are (still need to play more with this nice piece of SW) and will give you note, presumably tomorrow or wednesday the latest. 
13th July 2009, 09:46 PM  #326  
diyAudio Member
Join Date: Mar 2003
Location: Denmark, Copenhagen

Ffpo?
Quote:
http://www.eaw.com/Info/EAW%20Smaart...ndamentals.pdf Then FFPO is purely smoothing in the frequency domain. E.g. When I smooth with 1/N and N = 1 the point in 1000 Hz is an average (windowed) from 500 Hz to 2000 Hz See attachment And as far as I can google this is the same as FFPO? 

13th July 2009, 10:15 PM  #327 
diyAudio Member
Join Date: Apr 2007

Hey Guys,
Smaart's FPPO uses multiple FFT sizes of varying Time constants to give 24 points per octave. For instance at 48k Sample rate(SR) an FFT of of 32K gives a Time constant(TC) of 683ms for a Frequency resolution (FR) of 1.5Hz Broken into the approximate bands : 0 > 125 Hz, FFT 32K, TC 683ms, FR 1.5Hz 125 > 550Hz, FFT 8k, TC 171ms, FR 5.9Hz 550 > 2kHz, FFT 2k, TC 43ms, FR 23.4Hz 2k > 8kHz, FFT 512, TC 11ms, FR 93.8Hz 8k> Nyquist, FFT 128, TC 3ms FR 3750 Hope this helps,
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Warmest regards, Ferrit37 
13th July 2009, 10:21 PM  #328  
diyAudio Member
Join Date: Mar 2003
Location: Denmark, Copenhagen

Quote:
This FFPO is then a 5timewindow approach compared to the dualtimewindow. But is that a FFPO ? I lack a definition of FFPO. 

13th July 2009, 11:23 PM  #329 
diyAudio Member
Join Date: Dec 2004
Location: Novi, Michigan

The more logical thing to use is use the log sampled FFT that was published in the AES some time ago. This gives a constant number of points per decade with only a single FFT. Getting log sampled data from constant sampled data would not be too hard. Some interpolation thats all.
I'd love to see that done so that I could play arround with it. 
14th July 2009, 12:09 AM  #330 
diyAudio Member
Join Date: Apr 2007

It's FPPO
Fixed Points Per Octave and basically there's 24 points per octave hence 24FPPO As Earl says Log spaced or Fractional octave is the way to go (Smaart 7) hint Don Keeles paper on Logspaced FFT http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20(199411%20AES%20Preprint)%20%20Log%20Sampling.pdf cheers
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