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Phase Linear EQ with no pre ringing? Equalizer Plugins
Old 1 week ago
  #31
Lives for gear
 

If someone has finally created a plugin eq that doesn't flat out suck, what's not to like? I remember when the original versions first came out, fun toys! (but of course not transparent sounding)
Old 1 week ago
  #32
Gear Nut
 

Quote:
Originally Posted by JP__ View Post
Buying an exotic dongle for demoing is a huge bummer unfortunately (still have a early CodeMeter here, but this doesnt seem to work right?)...
Right. Confirmed at the source. Out of their hands they said, due to CodeMeter Libs.
Old 1 week ago
  #33
Gear Maniac
 

acourate - https://www.audiovero.de/en/acourate.php - seems to have so pre-ringing compensation. it's a room correction system also used by bob katz. it's not a vst, but it's as far as I understand a program to create digital filter.

not sure what pre ring compensation means exactly here and not sure how good it works. have anyone tried it by chance?
Old 1 week ago
  #34
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macc's Avatar
 

Verified Member
Been having this discussion on a mastering group on Facebook. Copy/pasting my own post...

From what I've read Uli saying, Acourate's PRC works by delaying the freq/s related to the pre-ring, usually which are tied to specific problem areas in the room response (sharp spikes in excess phase, etc). But Acourate's correction is mixed phase, so it doesn't matter in terms of 'it's no longer a linear phase correction', as it isn't intended to be. If, however, you used that approach with an eq, the impulse response would no longer be symmetrical = not linear phase any more. Hmmm.

Disclaimer: this post is mostly conjecture based on inference about Acourate's PRC, and my own inferior knowledge and understanding. Hopefully it makes sense though.
Old 1 week ago
  #35
Quote:
Originally Posted by macc View Post
Been having this discussion on a mastering group on Facebook. Copy/pasting my own post...

From what I've read Uli saying, Acourate's PRC works by delaying the freq/s related to the pre-ring, usually which are tied to specific problem areas in the room response (sharp spikes in excess phase, etc). But Acourate's correction is mixed phase, so it doesn't matter in terms of 'it's no longer a linear phase correction', as it isn't intended to be. If, however, you used that approach with an eq, the impulse response would no longer be symmetrical = not linear phase any more. Hmmm.

Disclaimer: this post is mostly conjecture based on inference about Acourate's PRC, and my own inferior knowledge and understanding. Hopefully it makes sense though.

But acourate is not an EQ in the traditional sense! Its a filter meant to undo the room's own "filter" (the acoustics).

No acoustics problem is lin phase in the first place, so why even use it?!

Again: Given linear phase specification, the filter magnitude (how flat, how sharp, how complicated) directly dictates the impulse response of the filter. There is ABSOLUTELY no choice, no room for creativity in this corner.

Last edited by FabienTDR; 1 week ago at 04:04 PM..
Old 5 days ago
  #36
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macc's Avatar
 

Verified Member
Quote:
Originally Posted by FabienTDR View Post
But acourate is not an EQ in the traditional sense! Its a filter meant to undo the room's own "filter" (the acoustics).

No acoustics problem is lin phase in the first place, so why even use it?!
Hi Fabien,

Not sure if I'm understanding your understanding of my post correctly

I wasn't saying that room effects are lin phase, but that Acourate uses FIR filters that can result in pre-ring when addressing certain things (points with wild excess group delay etc). It has a method for addressing that pre-ring which is fine for room correction, but *if* you are looking for a true LP response (as in this eq) then it cannot be used. That is the only point I was making.



Quote:
Again: Given linear phase specification, the filter magnitude (how flat, how sharp, how complicated) directly dictates the impulse response of the filter. There is ABSOLUTELY no choice, no room for creativity in this corner.
Absolutely, I agree 100%. There isn't any room not to disagree as it's a statement of pure fact
Old 5 days ago
  #37
Just to better illustrate why ripples pre and/or post the IR are to be expected in all useful cases:












Flat passband = Ripples in the impulse response
No ripples in the IR = No passband.


This is a logical consequence of the Fourier transform.

Min phase only produces post ripples,
and lin phase both pre and post ripples.
The examples shown above are all linear phase.

_
Attached Thumbnails
Phase Linear EQ with no pre ringing?-irripple_1.jpg   Phase Linear EQ with no pre ringing?-irripple_3.jpg   Phase Linear EQ with no pre ringing?-irripple_4.jpg   Phase Linear EQ with no pre ringing?-irripple_2.jpg  

Last edited by FabienTDR; 5 days ago at 06:53 PM..
Old 2 days ago
  #38
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gyraf's Avatar
Thanks, Fabien.

As always, I really appreciate and enjoy your explanations from this domain..

Jakob E.
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