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

[SwissBear]

Originally Posted by soundcheck

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...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

[pos]

Originally Posted by nc535

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.

[wesayso]

Originally Posted by SwissBear

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...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!

[SwissBear]

Originally Posted by wesayso

Now where is that like button when you need it, good post!

Thank you wesayso Your are very appreciated too

[SwissBear]

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 no longer works. Please upload images instead of linking to them to prevent this.

[nc535]

Originally Posted by pos

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

[SwissBear]

Hi everyone,

A short contribution, aimed at those who, like me, are starting on rePhase, and willing to learn more. How to use rePhase and REW to simulate systems' behavior: Using REW and rephase to generate amplitude and time domain corrections

[GiAnt1961]

Originally Posted by SwissBear

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

[pos]

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.

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

[SwissBear]

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