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Multi-Way Conventional loudspeakers with crossovers

rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool
rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool
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Old 14th January 2016, 08:28 PM   #901
zizione is offline zizione  France
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Quote:
Originally Posted by pos View Post
Did you get the polarity and t=0 of the measurement right?
This is important to get the proper visualization of phase shifts and correct... correctly. They have been some advice in the previous posts that you should follow.
What phase corrections have you been using?

Regarding amplitude correction, you should only use minimum-phase ones, and as for the phase correction try to keep things simple. You don't want to correct measurement artifacts (position related, or windowing related...).
Phase and amplitude corrections done (properly) at different position can be "mixed" without problem.
Minimum-phase EQ should also help solving some phase variation, and eliminate the need for some phase EQs.

Not not hesitate to share you corrections and/or measurements.
Hello,
Here are some visuals of :

left and right measurements in REW. I have not done specific settings except calibration of the microphone and setup of asio devices. All my measurements and corrections are done at 96 Khz.

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

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


I did not touch settings with regards to polarity and timing.

Then usage of rephase for phase correction with those settings :
For the left channel :
rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool

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

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

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


On this tab, I used 1/3 oct bands and corrected on the 3 of them

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



For the right channel :
rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool

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

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


Filters are well exported with success to Daphile or Fedolight, but the results are not so much noticeable... I'm sure I might do something wrong.

Also looking at the wave form in Audacity, there seems to be very few elements in the wave. Is this normal ?

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


Many thanks for your help
David
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Old 14th January 2016, 11:41 PM   #902
bohdan1232000 is offline bohdan1232000  Australia
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Quote:
Originally Posted by zizione View Post
Hello,
Here are some visuals of :

left and right measurements in REW. I have not done specific settings except calibration of the microphone and setup of asio devices. All my measurements and corrections are done at 96 Khz.
........
Many thanks for your help
David

Hi David,

Can you also provide REW measurements (SPL/phase) of the equalized loudspeakers at 70cm and 80cm?.

My apologies if you have already done so, but I somehow missed this - thanks.

Best Regards,
Bohdan
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Old 15th January 2016, 06:54 AM   #903
zizione is offline zizione  France
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Hi Bodhan, if you mean their import in rephase before correction, there you go :

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


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


Thanks
David
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Old 15th January 2016, 12:22 PM   #904
bohdan1232000 is offline bohdan1232000  Australia
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Quote:
Originally Posted by zizione View Post
Hi Bodhan, if you mean their import in rephase before correction, there you go :
Thanks
David

Hi David,

No, that is not what I was asking for.

I was interested in SPL and phase after correction.
This measurement should be taken at two locations: (1) at the same distance as the original measurements and (2) 10-20cm further away.

You have also provided already Audacity screen shot of what seems to be an impulse response of the equalized loudspeaker - am I correct?.
If this is the case, please expand the Audacity screen to full size of your PC monitor screen and change vertical axis to Logarithmic. It is useful to evaluate IR in logarithmic scale.

Best Regards,
Bohdan
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Old 15th January 2016, 02:57 PM   #905
jmbee is offline jmbee  France
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Hi David,

The JMR Cantabile are supposed to be filterd as:
" 6, 6 and 18 dB/octave
. Cut of frequencies 600 and
3800 Hz. The two woofers are working together
under 600 Hz. "

and can be seen like a two ways for xover.
If you look at global shape of the phase measurements, accidents free,( at 110 Hz ect ) it gives:

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


in rePhase ( time inverse ) just two settings: ( grosso modo ) to reach
the global shape, then some eq to add.

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


cdt
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Old 15th January 2016, 06:32 PM   #906
zizione is offline zizione  France
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Merci jmbee, I will try to create those shapes time inverted, revert and generate the filters and give a try and a measurement ! Good stuff to keep me busy over the weekend

David
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Old 15th January 2016, 07:07 PM   #907
BYRTT is online now BYRTT  Denmark
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rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool
zizione, have you zero aligned IR those REW mesurements before export to frd-file to use in Rephase.

Here a couple of ways prepare in REW before export to frd-file, no claim these is the only and right way.

In general its worth after a new measurement look in both "Distortion" and "Impulse" windows as first thing after a new measurement sweep, if anything there looks weird and collapsed sweep again. Many has no problem but many setups show measurement chain trouple at some sweeps probably caused by environmental interferences and sample rate converting somewhere. Frq response often looks fine therefor look into the other two windows to see these sweep flaws.

1:
After a measurement or opening a old saved one view window in either "SPL & Phase" or "Impulse" plot then hit "Controls" and "Estimate IR Delay". Now export that as frd-file to be corrected in Rephase.

2:
Above will have phase plot that is speaker + room, this one will form phase as to be same minimum phase plot that is associated the actual frq response. First do same as point 1 except do not export as frd-file but export as "Impulse Response as Wav" as in below picture 1. Now import that IR-wav-file and zero align it with "Estimate IR Delay" command and its now ready to be exported as frd-file to be corrected in Rephase.

EDIT for point 2 after hit "Estimate IR Delay" then button above it "generate Minimum Phase" need be pushed too else one gets error pointing to this subject under the export as "Impulse Response as Wav" command.

3:
This is same as point 2 but add a frq dependent 1/6 oct 4,3 cycles window so as correction made in Rephase is more based first front wave than room. Procedure is before export frd-file as in point 2 ensure at left side that imported IR-wav file is high lighted then hit icon "IR Windows" and set it as in below picture 2 and hit button "Apply Windows". Now export that as frd-file to be corrected in Rephase.

In all three points above IR will be aligned but big difference is what measurement present to Rephase to correct for in time domain, so one must judge what will be most right if measurement is taken at 0,5-1,0 meter distance or at listening position and how much room is really present into measurement. Point 2 and 3 is inspired from another thread subject starts in link A convolution based alternative to electrical loudspeaker correction networks.
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File Type: png 2.PNG (16.0 KB, 64 views)

Last edited by BYRTT; 15th January 2016 at 07:29 PM.
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Old 16th January 2016, 09:14 AM   #908
zizione is offline zizione  France
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Thanks BYRTT for your very detailed answer. I will try all or the 3 methods together with the one provided by Jmbee and see which results I get.
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Old 17th January 2016, 06:24 PM   #909
zizione is offline zizione  France
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Hi guys,
During the week-end, I have tested all methods. So far, I'm staying with Method 3 of BYRTT which provided the best improvement. It is quite amazing how deeper and clearer bass sounds, instruments are much more differentiated, space gained also a lot.
On complex messages like "Unsustainable" of Muse, everything is in place, and much clearer...
I'm going to continue a little bit my investigations, but I'm an happy guy right now...

Thanks Jmbee and BYRTT for your help
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Old 18th January 2016, 06:24 AM   #910
BYRTT is online now BYRTT  Denmark
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rePhase, a loudspeaker phase linearization, EQ and FIR filtering tool
Thanks feedback zizione had a look at Jean-Marie Reynaud web site your speaker model CANTABILESUPREME looks great.

Glad to hear method 3 was a better one, credit should go to gmad and wesayso over that thread i just passed info. Actually haven't tried method myself yet but there is some logic in it works as a good base to make correction in Rephase especially for listening position scenario and full range speakers with frozen XO by that mean a speaker where we can't DSP control each driver by their own. Think measurement method ensure to some degree we get most speaker and less room and what wiggles can be linearized for a minimum phase speaker with IRR EQ correction at first before we finalize with FIR to correct for IRR XO points phase turn and or continue and also correct for hole IRR system stop bands roll off.

Think it can be discussed as personal taste if one prefer real linear phase correct for hole IRR system stop bands roll off, i ran this myself for many months but think they over that thread at present prefer that phase follow IRR associated frq response.

Should you want to try that receipt then when you measure your new corrected system hit "Estimate IR Delay" then "Generate Minimum Phase" and continue edit new corrections in Rephase with FIR power methode as jmbee tipped until measurement of corrected system show same minimum phase (IRR) trace as actual phase trace is. For fun made FR/IR/SR/square wave plots for a smooth IRR band pass system BW2 30Hz - BW2 22kHz if it runs 96kHz sample rate for correction and measurements to model your speakers specs. Think below show IRR pass band system can throw very fine waveform when we FIR correct only XO phase distortion away, it doesn't need linear phase all the way down from DC up to lightspeed to produce nice speaker grade square waves.

Have tried with method 1 in one spot around 1 meter distance linearize frq as smooth and wide as possible and then add as wide and linear phase as possible, sound over crazy good listening in that spot but acoustics is unfortunately not as a electric wire that only has one route so sound elsewhere is certantly not as should be.
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Last edited by BYRTT; 18th January 2016 at 06:27 AM.
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