rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool

:confused: It was just recently announced the filter quality with REW plus rePhase is en par with Acourate nowadays. ( No word about the preringing issue though)
...
Folks, why do you stay so vague all the time???

Hi soundcheck,

I hesitated to answer because of the tone of your post :(

Having said that, you probably have to understand that Acourate has two goals, which are described here:
Computer Audiophile - Acourate Digital Room and Loudspeaker Correction Software Walkthrough
and there: Computer Audiophile - Advanced Acourate Digital XO Time Alignment Driver Linearization Walkthrough

rePhase has more to do with the second application of Acourate. This is why its usage in the room correction side of things is not well documented. But if you dig into this Guide to Speaker/Room Correction Using Freeware and JRiver, you will get some clue on how to use rePhase in a room correction process.

We are not here on the web to jeopardize the business of Acourate or Dirac. We are here to share our experience and explain how we were able to use some tools to make progress on our own. This is why I found useful to share my experience using rePhase in the room correction process.

Having said that Acourate is a fantastic tool too and I invite you to buy a license of it if you can. You will get very quickly and easily top corrections and will probably be very happy with it. This is BTW what I did too.

But if you want to dig deeper on your side, because you are willing to spend time understand how things work and share with a passionate community, I also invite you to spend some time looking at rePhase which is a fantastic tool brought to us by Pos.

Regarding pre-ringing, you probably need to read this: http://www.bodziosoftware.com.au/pre_post_ringing_ir_and_pulses.pdf which has been written by Bohdan who is active on this thread. I was able to get as I wrote very ugly as well as clean impulses with rePhase, in the same way that I was with Accourate. Depending on how you tune Acourate (number of cycles for the FDW) you can get surprising results. I will not share my worst experiments here but it can be surprising. On the other hand, if you are careful, you can get very good impulses with Acourate as advertised by Dr. Brueggemann. But, as I have written the other day, if you are careful to use minimum phase filters and minimum phase corrections, the behavior of your system will be as close as possible to a minimum phase system. In this case, you should not have pre-ringing on the impulses produced by rePhase either, although the tool in itself does not provide any optimization against pre-ringing.

Finally, my experience with room correction tools, and I have owned a Trinnov Amethyst, tried a Dirac license, own an Acourate license and spent some time looking at rePhase, is that all products can, depending on the way you use them, produce very good results. The difference between them is the implication you need to put into the process to get these good results and the money you are willing to invest. But keep in mind that the results you get will only be as good as the understanding you put into the design of your target curve and the quality of your measures. So as has been written, take your time to make measurements, understand things, read a lot.

And come back here to share your experience with rePhase if you are willing to contribute :)
 
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Never mind, found some pilot errors, answered my own questions, thinking there must be a better way but don't want a PC in my playback path
Jack, You can indeed use several EQ banks.
Regarding REW import, next version will have an import functionality in each bank, working toghether with the "rephase" equaliser that John implemented in the last Beta version of REW.
In the meantime (which should be short hopefully) you can still import EQ by hand.
You have to make sure the Q types are the same tho: if you are using the "minidsp" equaliser in REW then you should set the type to "proportional Q" in rePhase.
 
Hi soundcheck,

I hesitated to answer because of the tone of your post :(

Having said that, you probably have to understand that Acourate has two goals, which are described here:
Computer Audiophile - Acourate Digital Room and Loudspeaker Correction Software Walkthrough
and there: Computer Audiophile - Advanced Acourate Digital XO Time Alignment Driver Linearization Walkthrough

rePhase has more to do with the second application of Acourate. This is why its usage in the room correction side of things is not well documented. But if you dig into this Guide to Speaker/Room Correction Using Freeware and JRiver, you will get some clue on how to use rePhase in a room correction process.

We are not here on the web to jeopardize the business of Acourate or Dirac. We are here to share our experience and explain how we were able to use some tools to make progress on our own. This is why I found useful to share my experience using rePhase in the room correction process.

Having said that Acourate is a fantastic tool too and I invite you to buy a license of it if you can. You will get very quickly and easily top corrections and will probably be very happy with it. This is BTW what I did too.

But if you want to dig deeper on your side, because you are willing to spend time understand how things work and share with a passionate community, I also invite you to spend some time looking at rePhase which is a fantastic tool brought to us by Pos.

Regarding pre-ringing, you probably need to read this: http://www.bodziosoftware.com.au/pre_post_ringing_ir_and_pulses.pdf which has been written by Bohdan who is active on this thread. I was able to get as I wrote very ugly as well as clean impulses with rePhase, in the same way that I was with Accourate. Depending on how you tune Acourate (number of cycles for the FDW) you can get surprising results. I will not share my worst experiments here but it can be surprising. On the other hand, if you are careful, you can get very good impulses with Acourate as advertised by Dr. Brueggemann. But, as I have written the other day, if you are careful to use minimum phase filters and minimum phase corrections, the behavior of your system will be as close as possible to a minimum phase system. In this case, you should not have pre-ringing on the impulses produced by rePhase either, although the tool in itself does not provide any optimization against pre-ringing.

Finally, my experience with room correction tools, and I have owned a Trinnov Amethyst, tried a Dirac license, own an Acourate license and spent some time looking at rePhase, is that all products can, depending on the way you use them, produce very good results. The difference between them is the implication you need to put into the process to get these good results and the money you are willing to invest. But keep in mind that the results you get will only be as good as the understanding you put into the design of your target curve and the quality of your measures. So as has been written, take your time to make measurements, understand things, read a lot.

And come back here to share your experience with rePhase if you are willing to contribute :)

Now where is that like button when you need it, good post! :up:
 
To achieve a more complete answer on pre-ringing audibility, with the help of the paper of Bohdan and a manual replication, here are the measures I made on my system.

Conclusion: none of these correction systems are producing audible pre-ringing IMHO.

An externally hosted image should be here but it was not working when we last tested it.
 

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Jack, You can indeed use several EQ banks.
Regarding REW import, next version will have an import functionality in each bank, working toghether with the "rephase" equaliser that John implemented in the last Beta version of REW.
In the meantime (which should be short hopefully) you can still import EQ by hand.
You have to make sure the Q types are the same tho: if you are using the "minidsp" equaliser in REW then you should set the type to "proportional Q" in rePhase.

Hi Pos:
Thanks for your reply and for an invaluable tool! That is very good news about the import functionality!
Jack
 
Hi soundcheck,

I hesitated to answer because of the tone of your post :(

Having said that, you probably have to understand that Acourate has two goals, which are described here:
Computer Audiophile - Acourate Digital Room and Loudspeaker Correction Software Walkthrough
and there: Computer Audiophile - Advanced Acourate Digital XO Time Alignment Driver Linearization Walkthrough

..........

And come back here to share your experience with rePhase if you are willing to contribute :)
:worship::worship::worship:
 
rePhase 1.2.0 is out: http://sourceforge.net/projects/rephase/

Many thanks to John for implementing the rephase equaliser and export format in REW, skyunlimited for the beta testing, and SwissBear for his insightful feedback and ideas.

Code:
1.2.0 2016-12-08
  New features:
    - REW automated EQ settings generated using the 'rePhase' equaliser
      type (as implemented in REW V5.17 beta 14 and up) can now be imported
      directly into a paragraphic EQ bank
    - EQ points in paragraphic EQ tabs can now be individually bypassed
    - added a "tools" menu in paragraphic EQ tabs, effective on current
      bank:
      * load/save current bank into a '.eq' file as a JSON object
        (gain paragraphic EQ tab only)
      * load/save current bank into the clipboard as a JSON object to
        easily copy it to other banks or rePhase instances, or share it
        through forum posts
        (gain paragraphic EQ tab only)
      * import REW EQ settings generated with 'rePhase' equaliser type
        (gain paragraphic EQ tab only)
      * convert back and forth between constant and proportional Q types
        (gain paragraphic EQ tab only)
      * invert corrections
      * bypass or activate all EQ points
      * order by frequency, active or reversed order
    - "Help" menu entry (albeit probably not very helpful :( )
  Bug corrections:
    - The long lasting encoding issues with paths when loading, saving, and
      generating files should now at last be solved. It was already
      supposed to be the case in version 0.9.7, then 1.1.0, and should now
      *at last* be effective. Please report any problem with files or paths
      containing special characters (accents, etc.).
    - Corrected a bug introduced in version 1.1.1: fader position could
      sometimes change based on the position of the mouse cursor after
      loading or saving a file
    - Stop confining mouse cursor within faders, as it could stay stuck
      under some rare circumstances
  Adjustments:
    - set default optimization setting to none, as optimization process can
      increase preringing and should only really be used when the number of
      available taps is too limited to obtain the desired magnitude curve
    - increased default number of taps to 16384 to reflect an increase in
      CPU and DSP power in the last years (wishful thinking? :) )
    - boost FFT length calculation ratio to improve precision
    - changed default windowing algorithm from rectangular to hann for a
      more generic default behavior
    - EPS vector files screenshots including result curves are now
      significantly lighter and result in smoother curves compared to
      versions 1.1.0 and 1.1.1
    - suppressed flickering when switching between Views buttons
    - default to "Large" view mode
 
Hi Pos,

Thank you so much for your continued efforts and for this wonderful piece of software. Thank you to John too for his implementation of the interface of REW with rePhase.

Great job, wonderful collaboration :)

Agree much and also thanks your skills and sharings, at same hope its alright remind we can support other way if any of us non know how to code have some more or less coins left then both Rephase and REW have "Donate" buttons.
 
Hi,

What you are looking for is file association, the fact that windows can learn what program to start when you click a given file by looking at its extension.
The way this mechanism is handled has evolved in recent version of windows.

rePhase is just an executable file, and does not come with an installer that takes care of putting shortcuts in the start menu, or doing file association.

So this file association process, if needed/wanted, has to be done by the user. Right-clicking on a rephase settings file and then choosing the "open with" entry will let you choose an executable (you will have to actually browse to the exec file), and then you should be able to make it permanent (at least until next version, or until you move it, or?) by checking a button.

Thanks for your answer. I forgot to answer back.

I did try that, but somehow, even when I browse to the exec file, windows will not let me open it using Rephase. It might be a specific problem with my Windows.. ?
For now I just use the drag and drop method

Regards
 
Hello!

First of all I would like to say a big thank you for this great tool.
For my current project I would like to use a lowpass filter at 22 kHz to prevent that the 28 kHz resonance of the tweeter modulates into the lower frequencies and increases multisine distortion.
For this I plan to create an linear phase FIR filter with rePhase but I am not sure, how steep this can be without causing any problems. I created this filter with 400 taps at 96 kHz and 192 dB / octave.
Can such filters cause any audible problems like pre-ringing or something else? I changed the scaling to 50 kHz and -150dB and the rolloff was totally smooth.

Thank you!
 
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Acoustic Engineer, I am no expert on this but from what I remember from Doug Self's active crossover book except for the Butterworth and LR filters I think that all other filter types have some kind of pre or post ringing as a mathematical certainty. The question really becomes is that ringing from one of the alternate math function audible or are these ringing frequencies far enough down in level to be ignored?

My question for you in your particular situation with the driver you are dealing with is even with a fast slope at 28Khz what is the attenuation at 20Khz or even at 14Khz with the given slope you have chosen? It takes a pretty high slope to keep any harmonics from a really badly behaving device out of the pass band of the device, at the same time you have to look at what is exciting that high frequency breakup mode, or is it really only a problem when you are measuring with a wide bandwidth that is greater than our normal listening acuity? An input filter on many amps and other devices would seem to limit the possibility of exciting that 28Khz mode, besides the fact that most music has little to no information in that range.
 
Hi Mitch,

Thanks for the link.

BTW your book is awesome. Very useful to understand how to use rePhase/REW as well ;)

Kind regards,
Pierre

Hi Pierre,

I am glad you found the eBook useful. Like you say, while I use Acourate, the principles can be applied using most DSP software.

Interested folks can browse the Table of Contents and read the first couple of chapters by clicking on the link in my sig below and then clicking on Look Inside.

Kind regards, Mitch