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Old 28th May 2013, 12:30 AM   #431
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Quote:
Originally Posted by Jmmlc View Post
Hello Bohdan,

Be sure I am convinced that linearized phase audio system have their benefits and even if it seems so, I don't want to dimiss phase linearization where it provides its benefits.

That's only for the lower frequencies ( let's say less than 150Hz) for which I think that the audible benefits of phase linearisation are questionable...

Jean-Michel Le Cléac'h


Hi Jean-Michael,

Thank you for your comments.

Yes, you are correct, the benefits of linear-phase performance can not be dismissed. In my tests, the linear-phase subwoofer was a clear winner.

What specific linear phase tests have you conducted?.

Please describe the equipment, software used, test signals, documented test results and performance curves of your equipment, including EQs.


And most importantly, please provide acoustical test results of a square wave of several frequencies, played by your speakers.



Best Regards,
Bohdan
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Old 28th May 2013, 11:26 AM   #432
pos is offline pos  Europe
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Quote:
Originally Posted by bohdan1232000 View Post
Please describe the equipment, software used, test signals, documented test results and performance curves of your equipment, including EQs.


And most importantly, please provide acoustical test results of a square wave of several frequencies, played by your speakers.
Agreed, but please, pretty please, if those tests are not directly related to rePhase, publish them in another thread.

No offense meant, but I would really like to keep this thread on topic, that is a reference thread to help users find information about rePhase (which has no documentation outside of forum threads...) rather than general assumptions and experiences about linear-phase speakers
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Old 29th May 2013, 12:11 AM   #433
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Originally Posted by pos View Post
Agreed, but please, pretty please, if those tests are not directly related to rePhase, publish them in another thread.

No offense meant, but I would really like to keep this thread on topic, that is a reference thread to help users find information about rePhase (which has no documentation outside of forum threads...) rather than general assumptions and experiences about linear-phase speakers

Hi Pos,

No problem.

The title of this thread is “rePhase, loudspeaker phase linearization, EQ and FIR filtering tool”. Since we are talking about loudspeaker phase linearization, therefore this conversation sits very well within the title and scope of this thread.

This conversation is not off-topic.

It would only be fair and courteous to give Jean-Michel and opportunity to explain his “hands-on” involvement in linear-phase loudspeaker testing, rather than cutting him off, half-way through the sentence.



Best Regards,
Bohdan
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Old 29th May 2013, 03:15 AM   #434
dlr is offline dlr  United States
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Quote:
Originally Posted by bohdan1232000 View Post
The title of this thread is “rePhase, loudspeaker phase linearization, EQ and FIR filtering tool”. Since we are talking about loudspeaker phase linearization, therefore this conversation sits very well within the title and scope of this thread.

This conversation is not off-topic.
I think I get his meaning. He left out a single letter in the topic that would make it more clear. The title he intended, I suspect, should have been

“rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool”.

My impression is that he's attempting to focus on his tool, not the topics in general.

Dave
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Old 29th May 2013, 05:13 AM   #435
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Originally Posted by dlr View Post
I think I get his meaning. He left out a single letter in the topic that would make it more clear. The title he intended, I suspect, should have been

“rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool”.

My impression is that he's attempting to focus on his tool, not the topics in general.

Dave

Hi Dave,

Good point – thank you.

However, Jean-Michel needs to come back with the answers. If he used rePhase, this thread is good to continue as Pos requested.

Best Regards,
Bohdan
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Old 29th May 2013, 08:35 AM   #436
Jmmlc is offline Jmmlc  France
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Quote:
Originally Posted by bohdan1232000 View Post
Hi Dave,

Good point – thank you.

However, Jean-Michel needs to come back with the answers. If he used rePhase, this thread is good to continue as Pos requested.

Best Regards,
Bohdan

Hello Bohdan,

I never spoke about rephase itself but about the few experiments abaout phase linear filtering, phase linearization I am not originator of, but to which I attended. (During the European Triode Festival or during a meeting of the asssociation Melaudia I am member of which, during private listening sessions, etc.).

A friend of mine gave me the IR of his phase linearized system which show some long very low frequency pre-ringing. I'll see if I can share that IR.

But my own experience on such subject is not zero as few seems to suggest, as I was probably in France one of the first to experiments with the tools developped by Angelo Farina long time ago (convolution, Kirkeby, inverse filtering...) .

My opinion is that the benefits of phase linearization is more audible with bad loudspeakers and crossovers. With good one I don't hear so much improvment... I only post my opinion here as some food for further thoughts. Do what you want of it.

Finally I would say that we can do a parallel between phase linearization and directivity control. They both provide some benefits, but there is so many and more basics improvments of an audio system that can lead to greater benefits and that should be done before ...

Best regards from Paris.

Jean-Michel Le Cléac'h
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Old 29th May 2013, 11:33 AM   #437
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Already posted in this thread

loudspeakers with passive xover linearized with rePhase.(at 4 feets)

measured at listening point (10 feets).

Click the image to open in full size.
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Old 31st May 2013, 02:49 PM   #438
pos is offline pos  Europe
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Quote:
Originally Posted by dlr View Post
I think I get his meaning. He left out a single letter in the topic that would make it more clear. The title he intended, I suspect, should have been

“rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool”.

My impression is that he's attempting to focus on his tool, not the topics in general.

Dave
Hi Dave,

I thought the "tool" word at the end (without an "s") made the sentence clear enough, but it appears it was not the case (language barrier, sorry...).

Thanks for that. I edited the title in the first post, but it looks like the title thread did not change (yet). I will let some time for the server to reindex the title thread and will eventually contact a moderator to get it modified if this does not work automatically...
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Old 8th July 2013, 12:49 PM   #439
more10 is offline more10  Sweden
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I am hacking on my ADSP-21469. Currently I am trying to get the FIR accelerator to work, I will be using it for downsampling. In order to get some filter parameters i downloaded rePhase.

Can I use the output as FIR coefficients?
Is low-pass/reject high good enough for anti-aliasing?

It would be nice if you added "c array" as an output format option. Also a "reverse c array" would be nice since the FIR code wants the coefficients in reverse order.
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Old 8th July 2013, 01:24 PM   #440
pos is offline pos  Europe
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Hi

For anti-aliasing with a minimum number of taps (keeping power for actual processing) you should try the steepest possible filter (eg 1000dB/oct LR), a nuttall window (best ripple rejection most of the time), see what you get for a given (and small) number of taps, and lower the cutoff frequency until you get a decent rejection at targeted Nyquist, and a flat enough response within the intended range.
In fact in this case it is the number of taps that will dictate the slope.
Of course the larger the number of taps, the better (better rejection, and flatter inband amplitude)

Here are some simulations: (in french sorry for that, but the screenshots alone should be self-explanatory)
Le sujet Najda: une carte DSP pour applications HP - Page 4 du forum Correction active et logiciels de mesure sur Homecinema-fr.com - 30034920 - 1291

Regarding the output format, the closest to a C array that you can use will probably be the txt format. You should be able to transform that in a C array by automatically turning the carriage returns into commas with a good text editor.

I will add the C array (and possibly the reverse one, if it is a common practice... even if that feels a bit strange??) in the next version, but I don't know when I will release it yet.
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Last edited by pos; 8th July 2013 at 01:48 PM.
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