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Multi-Way Conventional loudspeakers with crossovers

How to improve step response
How to improve step response
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Old 18th January 2019, 01:41 AM   #41
mark100 is offline mark100  United States
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No offense, but until you show measurements that separate group delay into the components of physical distance and the 'phase growth' you speak of, the plots don't support a claim that group delay can be compensated for by delay. There's no way to know what is what.

As acknowledged, a Harsch crossover is a mixed type and order crossover that utilizes delay in it's alignment. I say it is not typical, and does not make any case whatsoever for using delay to compensate for group delay in linkwitz-riley, butterworth, or bessel crossovers.

Please show otherwise...

Oh, and another asked again please ... is your term 'phase growth' what the rest of us would call group delay, or perhaps increasing group delay?
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Old 18th January 2019, 07:15 AM   #42
phase_accurate is offline phase_accurate
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What we are still missing are generally valid maximum figures for group delay distortion perception.
Although I have developed active rossovers with almost perfect temporal response I am convinced that absolute perfection is probably not necessary to audibly satisfy even the most transient-susceptible listeners.
The avantage of transient-improved crossovers (like the Harsch and other time-aligned topologies) over transient-perfect ones would be the easier implementation, better lobing characteristics (OK, that restriction is not valid for some digital implementations) and much relaxed driver requirements.

But I agree, group-delay compensation by applying simple delay to any old crossover topology doesn't work.

Regards

Charles
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Old 18th January 2019, 08:16 AM   #43
merlin el mago is offline merlin el mago  Europe
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Quote:
Originally Posted by Lojzek View Post
Using crossover data in post #4 and files in post #23.
It seems the same step response like mine post #23.
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Old 18th January 2019, 08:36 AM   #44
zbig001 is offline zbig001  Poland
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Forgive me in case of my ignorance, but Seas Millennium section should not run through hpf output of the midbass speaker?
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Old 18th January 2019, 08:39 AM   #45
KSTR is offline KSTR  Germany
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Today, constructing analog transient-perfect speaker is moot. Just build the best speaker you can without taking care about total phase, rather match phases of all ways perfectly (unless for D'Appolito, where zero inter-driver phase isn't the proper phase offset for correct lobing).

Just unroll the total phase by manipulating the source signal with a proper digital filter. Unless you're playback chain is completely analog this filter always can be inserted in some way with no additional complications.

Only thing you must know for this is the excess phase (the phase of the allpass function that a typical crossover represents), preferably in analytical form. Take the time inverse of its impulse response and feed that into a convolver, most software players or renderers (in case of streamers) will allow for convolver plugins.

Done, with zero cost and zero ill-effects.
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Old 18th January 2019, 08:43 AM   #46
zbig001 is offline zbig001  Poland
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I think that even if we use very long FIR filters, this should not be perceived as panacea for every situation.
Especially in present times, when the top frequency supported in our digital track is by no means 20 kHz, only much more...
The higher this frequency, the worse should be behavior of FIR filters in phase and amplitude at the bottom (not enough taps to cover this range).
To my ears only IIR filters are actually suitable for treating the low frequencies.
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Old 18th January 2019, 08:46 AM   #47
Lojzek is offline Lojzek  Croatia
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Quote:
Originally Posted by merlin el mago View Post
It seems the same step response like mine post #23.

Yes it does. There is room for improvement in your filter. Impedance at 200 Hz is unnecessary low. And try to make frd files as suggested in white paper "How to Achieve Accurate In-Room Quasi-Anechoic Free-Field Frequency Response Measurements Down to 10 Hz". Need Excel to perform merging of near field response with baffle step applied to it, and far field response, and creating frequency response tails in FRD Response blender.
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Old 18th January 2019, 08:49 AM   #48
KSTR is offline KSTR  Germany
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Quote:
Originally Posted by phase_accurate View Post
What we are still missing are generally valid maximum figures for group delay distortion perception.
This is true but it seems to be extremely individual and also depending on the source material.

But it's really easy to conduct your own experiments and come to conclusions.

See previous post for the prerequisite, a perfect phase-coherent and also transient-perfect speaker. Then add in a bunch of analytically derived phase distortion kernels (including the polarity inverted versions) and check if this is audible or not. There is little published research on this you we have to this our own.
Personally, I've found for example that with headphones the sensitivity to phase distortion is way lower than with speakers in a real room so I don't recommend using them (and that's why many published result may not be valid because they've been established with headphones).
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Old 18th January 2019, 11:29 AM   #49
merlin el mago is offline merlin el mago  Europe
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Quote:
Originally Posted by Lojzek View Post
There is room for improvement in your filter.
Thank you, let me how?
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Old 18th January 2019, 12:28 PM   #50
plasnu is offline plasnu  United States
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Quote:
Originally Posted by zbig001 View Post
To my ears only IIR filters are actually suitable for treating the low frequencies.
Every digital filter out there sounds different for some reasons, so IIR can be better than FIR in some cases.
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