EASY FIR crossover PC based+DRC - Page 5 - diyAudio
Go Back   Home > Forums > Source & Line > PC Based

PC Based Computer music servers, crossovers, and equalization

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 12th December 2012, 08:44 PM   #41
diyAudio Member
 
Join Date: Jan 2006
Location: grenoble
Hi Boden,

you can easily try it on,just install VSThost,SIR v1.011,and generate 1 stereo flat impulse (2000 or 4000 taps ).with rePhase.
it's very quick to do.no need to create a crossover file,just add plugin with stereo connection,and load impulse.wav for each one.

i think a P3 processor can do the job.
just reduce number of impulse taps (samples).according to the desired slope and ripple level.

electovoice DX46 FIR crossover+FIR EQ ,512 taps max for each channel.
the processor inside is certainly less powerful than a P3.

Click the image to open in full size.
  Reply With Quote
Old 12th December 2012, 09:34 PM   #42
diyAudio Member
 
Join Date: Jan 2006
Location: grenoble
the same config is used with jriver
jriver has a native convolver filter (vst convolver )

install asio4all
install jriver media center or jukebox

open tool-->options-->dsp

Click the image to open in full size.

add plugin as shown below (convolver filter is a native one ).

Click the image to open in full size.

and like VSThost before ,load the config.txt for the crossover.
you can add SIR v1.011 too,for DRC convolution

Click the image to open in full size.
  Reply With Quote
Old 14th December 2012, 09:40 AM   #43
diyAudio Member
 
Join Date: Jan 2006
Location: grenoble
to drive a stereo amplifier in a bridged mode:

this is an example for lowpass+subsonic+bassboost impulse.

when generating impulse with rePhase,in the "general" tab,choose "polarity inv"

signal will be shifted to 180

Click the image to open in full size.

you can check it with REW.
but some minor setting has to be done.

import the impulse.wav with REW,as we can see,phase is not "flat".
because REW do not centering the impulse.

Click the image to open in full size.

need to centering IR by adjusting delay ,and manualy center it at t=0.
this is only to work with REW,nothing to do with VSTconvolver.
HOLM is more accurate.

Click the image to open in full size.

result

Click the image to open in full size.

and a the second with 0 phase shift.
you can drive a stereo amp (if it's possible ) in a bridged mode.

Click the image to open in full size.

with a flat response Impulse,you can drive a XLR symetric input.

Last edited by thierry38efd; 14th December 2012 at 09:53 AM.
  Reply With Quote
Old 14th December 2012, 10:10 AM   #44
diyAudio Member
 
Join Date: Jan 2006
Location: grenoble
when working with holm to simulate or making manualy convolution.

it seems that the only way to work with IR is to use .TXT files

impulse.txt
frequency.txt
(if you are opening measurement,export slot X.txt and import immediately the slot X.txt)

sometimes,import impulse.txt need to centering impulse.

Click the image to open in full size.

and when C=AxB or C=A/B do not show the new curve.
a simple way is to reset setting,it does not cancel the actual curves.
for me,it's working every times.

Click the image to open in full size.

Last edited by thierry38efd; 14th December 2012 at 10:33 AM.
  Reply With Quote
Old 16th December 2012, 04:35 PM   #45
diyAudio Member
 
Join Date: Jan 2006
Location: grenoble
difference between classic digital (or analog ) equalizer.

a correction made with REW EQ (minimum phase ) and the group delay.

Click the image to open in full size.

Click the image to open in full size.

using FIR EQ does not affect the phase.

-with rephase,EQ tab.
-LPGEQ (linear phase graphic EQ) 62 bands vst plugin.
to add in J river or any VSThost

VST plugins [slim slow slider presents]

Click the image to open in full size.

Last edited by thierry38efd; 16th December 2012 at 04:44 PM.
  Reply With Quote
Old 17th December 2012, 02:45 PM   #46
diyAudio Member
 
Join Date: Jan 2006
Location: grenoble
Quote:
-LPGEQ (linear phase graphic EQ) 62 bands vst plugin.
to add in J river or any VSThost
after a real try,LPGEQ has no enough resolution below 1 kHz.

to reduce CPU load:
generate lowpass IR with the necessary lenght .
generate hipass with lower lenght.

example:
FS=48kHz
lowpass IR.wav 4800 taps --> IR lenght 100 ms
hipass IR.wav 1200 taps -->IR lenght 25 ms

(a kind of manual warped FIR )

in the config file,delay the shorter IR by the difference of lenght.
75 ms here.

48000 2 4 0
0 0
75 75 0 0

g:\hipass.wav
0
0.0
0.0
g:\hipass.wav
0
1.0
1.0
g:\lowpass.wav
0
0.0
2.0
g:\lowpass.wav
0
1.0
3.0


this case is for very,very slow CPU.(i.e netbook or old laptop )
we can do the same with bandpass etc...

the total delay is define by the longest IR (hipass and lowpass in the low frequency ).

Last edited by thierry38efd; 17th December 2012 at 02:50 PM.
  Reply With Quote
Old 19th December 2012, 01:09 PM   #47
diyAudio Member
 
Join Date: Jan 2006
Location: grenoble
to simplify channel routing:

the config file is more simple.with one command line,convolver can sum the ch input or the ch output

example
stereo + subwoofer (ch 3 )

48000 2 3 0
0 0
0 0 20 (you can add delay for sub placement)
c:\impulse\hipass.wav
0
0.0
0.0
c:\impulse\hipass.wav
0
1.0
1.0
c:\impulse\subwoofer.wav
0
0.5 1.5 convolution input ch 0,1 (-6 dB)
3.0 to channel 3 (subwoofer)



example stereo to five loudspeakers

48000 2 5 0
0 0
0 0 0 30 30 (30 ms delay for the rear speakers)
c:\impulse\flatresponse.wav
0
0.0
0.0 2.0 (left to front left and rear left)
c:\impulse\flatresponse.wav
0
1.0
1.0 3.0 (right to front right and rear right)
c:\impulse\flatresponse.wav
0
0.5 1.5 convolution input ch 0,1 (-6 dB)
4.0 to channel 4 (center speaker)

there are lot of possibility

Last edited by thierry38efd; 19th December 2012 at 01:19 PM.
  Reply With Quote
Old 22nd December 2012, 11:34 PM   #48
diyAudio Member
 
Join Date: Jan 2006
Location: grenoble
Default group delay correction

how to correct all loudspeakers group delay (phase distortion ).

it concerns all speakers:
passive crossover
active+passive crossver
active crossover


and any acoustic phase distortion
-vented box
-closed box
-horn speaker


need only one convolution engine (or mix phase correction with crossover ).

a measurement of one loudspeaker at 1m is used.
and rePhase (tab filter linearization )

at the begining,it was the first (and the only one ) purpose of rePhase.
this is the most interesting and technical work to do.FIR EQ/crossover is very simple.

example of a correction in a midfield measurement

Click the image to open in full size.

the idea is to create an opposite delay to those of the spekaer in his box.

phase rotation is not a problem,when rotation is constant.
a linear phase system can have rotation.

example:3 linear phase rotation

Click the image to open in full size.

group delay in this 3 cases is constant.

group delay at 1M (3 feets) and correction to apply
Click the image to open in full size.

with rephase the tab "filter linearization is used.
-entry the slope/frequency of all your cross-over (passive or analog (and IIR filter too ).
-entry acoustic load
-choose any analog correction in the low frequency (subsonic+bassboost...)

Click the image to open in full size.

this is the theory parameter of your system,slope,frequency,bassreflex...

my loudspeaker without phase linearization

Click the image to open in full size.

and after lnearization,note the phase correction does not affect magnitude
this is 2 independants curves.

Click the image to open in full size.

Last edited by thierry38efd; 22nd December 2012 at 11:39 PM.
  Reply With Quote
Old 26th April 2013, 09:42 PM   #49
diyAudio Member
 
Join Date: Jan 2006
Location: grenoble
Hi,for those using a VST HOST,
most imporant subject to get all convolution for all applications.
a new FREE "virtual cable" by VB-Audio Virtual Cable
  Reply With Quote
Old 22nd May 2013, 07:10 AM   #50
diyAudio Member
 
soundcheck's Avatar
 
Join Date: Mar 2005
Location: D
Hi there.

Very interesting project.

I've got some questions

1. Acourate DRC seems to do rather successful preringig reduction.
People are pretty positive about that feature which was developed
not long ago after years of having that preringing i.

Is rephase taking any actions to reduce the FIR filter associated preringing??


2.

Kind of off-topic??

Has anybody ever tried to generate Ambiophonics filters

Cheers
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
iDFT-based XOs (FIR) steph_tsf Digital Line Level 15 5th November 2013 10:59 PM
AVX based FIR VST, crossover / EQ / DRC and delay KOON3876 PC Based 97 26th November 2012 07:18 AM
Is there any PC based software to crossover the L & R channels to the sub? spot PC Based 11 29th November 2011 11:46 AM
Looking for a New PC based Loudspeaker Crossover - What is available? mikaljones21 PC Based 9 28th June 2010 02:53 PM
Linux XO/DRC Fanless PC w. Lynxtwo jon_denmark Digital Source 6 20th July 2007 06:54 AM


New To Site? Need Help?

All times are GMT. The time now is 08:23 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2