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Author Topic: delay estimation and measurement  (Read 16430 times)

Raimonds.Skuruls

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Re: delay estimation and measurement
« Reply #10 on: February 16, 2014, 07:05:38 am »

Hi Raimonds,

Perhaps these links might be of interest to you!

http://www.fulcrum-acoustic.com/assets/pdf/whitepapers/spectrogram-loudspeaker-transient-response-2005.pdf
http://www.fulcrum-acoustic.com/assets/pdf/whitepapers/improving-loudspeaker-transient-response-with-dsp-2005.pdf
http://www.fulcrum-acoustic.com/assets/pdf/whitepapers/us8081766B2-creating-dsp-filters-improve-transient-response.pdf

Best regards,

Arthur
Sveiks, Artūr,

Thank you very much for links to those papers!
But seems like those works are still ideas (patent law view) for almost 10 years.
Evan patent is not describing the invention such way that it can be implemented without additional research work. It can not be prior art.
Pictures of those works have some similar properties to my work due to Heisenberg-Gabor limit.
Anyway, I have not seen any, ready to use in field, solution to show delays in easy readable way allowing to judge systems tuning quality in some seconds and than allowing tuning delays by direct measurement thus excluding errors due to derivate calculation when information about delay is acquired from heavy disturbed phase measurements.
BR,
Raimonds Skuruls
http://aplaudio.com

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Timo Beckman

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Re: delay estimation and measurement
« Reply #11 on: February 17, 2014, 07:03:50 am »

Would be nice to see this kind of "perfect" looking measurements at different mic positions so onax and more important ofax 15/30/45/60dg etc mic positions.

If i do a measurement on what ever brand of speaker it can be nice to have a "perfect" response onax but if the ofax positions suck i have some more work to do (at least in my book) because the majority of people are at the ofax positions

If a loudspeaker has a perfect onax phase/magnitude response but a not so perfect ofax response there has to be a compromise between the all mic positions.
« Last Edit: February 17, 2014, 07:10:19 am by Timo Beckman »
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Martyn ferrit Rowe

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Re: delay estimation and measurement
« Reply #12 on: February 17, 2014, 07:19:15 pm »

Hi Raimonds,
You might find this interesting, Wavelet analysis that's used in Clio by Audiomatica.
http://www.audiomatica.com/wp/wp-content/uploads/2012/03/audaesny2007.pdf

Also there's a couple of MatLab packages for wavelet analysis.
cheers
ferrit
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Raimonds.Skuruls

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Re: delay estimation and measurement
« Reply #13 on: February 18, 2014, 06:40:40 am »

Would be nice to see this kind of "perfect" looking measurements at different mic positions so onax and more important ofax 15/30/45/60dg etc mic positions.

If i do a measurement on what ever brand of speaker it can be nice to have a "perfect" response onax but if the ofax positions suck i have some more work to do (at least in my book) because the majority of people are at the ofax positions

If a loudspeaker has a perfect onax phase/magnitude response but a not so perfect ofax response there has to be a compromise between the all mic positions.
The „perfect" looking measurement” of delays is almost not dependant on a direction. Especially, for the coaxial design. If we have 3 ... 4 bands stocked vertically, we will have no dependence in horizontal plane and very small (negligible) in vertical plane. Hardest case is when different bands are fare from each other. We can make timing alignment just for one, most important direction in such case.


My friend John from Los Angeles sent me his first measurement of his studio monitors. I never can predict, that studio monitors may have such serious timing error – LF band is delayed for about 20 ms and crossover point is smear out. Please find picture attached.

The problem of controlling the speaker’s radiation in all directions is my previous work.
The key word in such problem is Sound (Acoustic) Power Frequency Response.
It is historically well forgotten thing. Tens of years ago the Reverberation Chambers (opposite to anechoic chamber) have been used to measure sound (acoustic) power emitted by speaker. And lot of works are pointing to importance of this and talking about this. Let’s stop talking and start doing. Let’s measure SPFR and create correction for it.  http://aplaudio.com/conc2/spfr/
Quote
Hi Raimonds,
You might find this interesting, Wavelet analysis that's used in Clio by Audiomatica.
http://www.audiomatica.com/wp/wp-content/uploads/2012/03/audaesny2007.pdf

Also there's a couple of MatLab packages for wavelet analysis.
cheers
ferrit
Thanks, Martyn, for valuable information. It will be addition to my collection of project names that are working on similar problems.
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Raimonds.Skuruls

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Re: delay estimation and measurement
« Reply #14 on: March 01, 2014, 08:17:27 am »

At least two topics are about “align subs to mains” here.
Let’s see how to achieve this taking in to account everything – crossover filter responses, equalizer filter responses, particular loudspeaker resonances, physical placement of boxes.
http://forums.prosoundweb.com/index.php/topic,148587.msg1364464.html#msg1364464

BR,

Raimonds
http://aplaudio.com
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Raimonds.Skuruls

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Re: delay estimation and measurement
« Reply #15 on: April 01, 2014, 08:33:18 am »

Two posts early I wrote about John’s problems with his monitors.
Actually, the monitors are Quested V3110  for about 4000$ each.
We did some work and get results.
Please find pictures attached.
1)   an initial AFR,
2)   an initial TDA delay graph,
3)   an AFR after minimum phase correction of AFR,
4)   a TDA delay graph after minimum phase correction of AFR,
5)   a TDA delay graph after delay correction.

And impressions of John:
 "Last night I listened to a project I recorded in 2005, I have listened to the project hundreds of times over the years. I heard details that I forgot were there like speed changes in the Lesile speaker and small inflections in the back up vocal. The reverb detail was un believable. It brought back memories of every detail of the sessions. The guitar tone reminded me of the guitar players amp and the mic I used. Over all I am very impressed with the correction, the detail is like headphones. I still need to work on the room some more and I would like a little more high end. More as I listen.
Thanks, John"

BR,

Raimonds
http://aplaudio.com
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Raimonds.Skuruls

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Re: delay estimation and measurement
« Reply #16 on: November 19, 2014, 07:09:58 am »

TDA software gets new function – Non Linear Distortion analysis.
Now we can see frequency response of each particular harmonic.
Please find attached Non Linear Distortion analysis graph that is showing
almost 10% NLD at 2 kHz for some concert hall system.



BR,
Raimonds
http://aplaudio.com
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Raimonds.Skuruls

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Re: delay estimation and measurement
« Reply #17 on: November 26, 2015, 02:54:48 am »

Hello Colleagues,

The discussion with Dr. Floyd Toole about his paper
"The Measurement and Calibration of Sound Reproducing Systems"
should be interesting to you.
The paper and start of discussion is available at AES forum:
https://secure.aes.org/forum/pubs/journal/?ID=524
Than the administrator of AES forum William McQuaide have decided:
"So we do not think that our readers will benefit from further postings" and denied next post.
All discussion is available here: http://aplaudio.com/downloads/Reading_Dr_Toole.pdf
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