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Old 11th July 2012, 02:50 AM   #21
Pano is online now Pano  United States
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I tried PORC EQ this morning thanks to the help of Greenm01. First listen is very promising, I'll get to experiment with it more later this week and will report back here. Well worth a try, I'd say.
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Old 12th July 2012, 07:48 PM   #22
jlo is offline jlo  France
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Hi all,

before trying PORC on my speakers, I did a simulation.
Hereunder are :
my home left speaker without correction / same speaker with DRC-FIR normal correction / convolved response with PORC

Click the image to open in full size.

Step responses as above, DRC corrects phase response but PORC doesn't
Click the image to open in full size.

Phase responses compared ( the blue is DRC-FIR corrected)
Click the image to open in full size.

As PORC doesn't have microphone curve compensation, please forget response above 12kHz (I couldn't compensate for this yet)
Nice work, PORC seems very promising. I'll have to take time to listen and compare now.
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Last edited by jlo; 12th July 2012 at 07:57 PM.
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Old 12th July 2012, 08:14 PM   #23
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Quote:
Originally Posted by jlo View Post
DRC corrects phase response but PORC doesn't
Can you please explain how the DRC-FIR phase response is a correction, based on these graphs? There exists no convenient test that delivers an easily understood quality rating for phase. Given our insensitivity to phase, the real question should be: does it matter in a normal listening environment?

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As PORC doesn't have microphone curve compensation, please forget response above 12kHz (I couldn't compensate for this yet)
I didn't include mic compensation in PORC becuase the software I use (Room EQ Wizard) already compensates for it.

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Nice work, PORC seems very promising. I'll have to take time to listen and compare now.
Thanks. I would like this to be a community project; open to improvements and suggestions.
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Old 13th July 2012, 06:52 PM   #24
jlo is offline jlo  France
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Quote:
Can you please explain how the DRC-FIR phase response is a correction, based on these graphs?
The step response in the middle is the one corrected with DRC-FIR and shows a corrected phase response. In the lower picture, the blue curve is the DRC-FIR phase and it is mostly flat, showing correction compared to the uncorrected green one.
But I agree with you, phase response is far less important than amplitude response.

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I didn't include mic compensation in PORC becuase the software I use (Room EQ Wizard) already compensates for it.
Does it mean that REW can export with mic compensation ?

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I would like this to be a community project; open to improvements and suggestions.
Sometime ago I did a GUI for DRC-FIR, so I just added PORC calculation, but, sorry, only for Windows and no real manual : http://www.ohl.to/audio/downloads/align2.zip
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Last edited by jlo; 13th July 2012 at 06:56 PM.
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Old 13th July 2012, 08:27 PM   #25
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Quote:
Originally Posted by jlo View Post
Does it mean that REW can export with mic compensation ?
HOLMImpulse certainly can. That's what I used.
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Old 13th July 2012, 08:35 PM   #26
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Quote:
Originally Posted by jlo View Post
The step response in the middle is the one corrected with DRC-FIR and shows a corrected phase response.
How do you know that the DRC-FIR "correction" is true to the uncorrected input? Based on the second graph, neither PORC nor DRC-FIR look like (visually) the uncorrected phase.

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Does it mean that REW can export with mic compensation?
Yes.

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Originally Posted by jlo View Post
Sometime ago I did a GUI for DRC-FIR, so I just added PORC calculation
That's interesting. I've used some of your VST plugins before and I like your GUI. I haven't had time to look your PORC plugin, but that would be great if PORC had a user friendly front-end. It would be even better if it was a standalone package without having to manually install all the Python dependencies.
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Old 13th July 2012, 08:38 PM   #27
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Old 4th September 2012, 07:19 PM   #28
jlo is offline jlo  France
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Hello Greenm01,
Just received my OpenDRC and made some tests.
I use Align2 as a GUI frontend http://www.ohl.to/audio/downloads/align2.zip, and I use the target files of DRC-FIR.
Everything works with PORC but not the target function. With mostly flat curves, no problem, but when you try to compensate for mic correction or choose curves with some boost in low frequencies, then you can get strange results, ie here is PORC with bk-3-subultra-spline-48.0.txt
Click the image to open in full size.
Any clue ? (I'm not a Python user but I will try to understand).
Anyway, with PORC, you've brought us a very nice tool..
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Old 4th September 2012, 07:55 PM   #29
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Default error/bug

Quote:
Originally Posted by jlo View Post
Any clue ? (I'm not a Python user but I will try to understand).Anyway, with PORC, you've brought us a very nice tool..
I purposly did not include microphone compensation in PORC because I already have it included with my recording software (Room EQ Wizard).

In regard to the target curve error there may be a bug or improvement that I can make to my spline function in Python. Thanks for pointing this out. Will you please post 'bk-3-subultra-spline-48.0.txt' so I can test it myself?
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Old 5th September 2012, 12:43 PM   #30
jlo is offline jlo  France
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Hello,

here is a test target where I'd like to keep a bit of boost in lower frequencies :
30 -6
40 0
50 4
400 0
3000 0
10000 -2
18000 -6
here is the result !
Click the image to open in full size.


now a bit modified
10 -60
30 -6
40 0
50 4
400 0
3000 0
10000 -2
18000 -6
20000 -60

it gets better but the bass boost is nowhere :
Click the image to open in full size.

Spline curve calculations are allways tricky : would it be possible to avoid splines ?
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