Time alignment of drivers seems to me to simply be alignment in the z (back to front) axis, so I don’t see how that would be less important than aligning drivers in the y (vertical) or x (horiz, use a coax) axis?
Thx, glad it made sense.Very interesting, I learned a lot, thank you. I am still a little fuzzy on some details. After reading your post my understanding is that linear phase crossovers don't ring because the ringing is cancelled out by the two filters at the crossover point. So here a few questions. How about minimum phase crossover filters and post ringing? Seems like they would be more prone to ringing? It is popular with DIY digital crossovers to not use the exact same slope or even the exact crossover point in order to "blend" the drivers together from flatter FR but with what you are saying this would be a bad idea from the "ringing" standpoint. Is that right? Do you have any insight into how audible "ringing" is for either crossovers or independent high and low pass filters? Thanks
I like this, and sort of tried it…but with Minidsp 2x4 hd there’s not enough fir taps to correct out of band phase and gain (or at least I couldn’t figure it out adequately). I was trying to equate the two drivers an octave out of band prior to L-R crossover.The idea of flattening out-of-band, prior to adding xovers
Aah cool!I like this, and sort of tried it…but with Minidsp 2x4 hd there’s not enough fir taps to correct out of band phase and gain (or at least I couldn’t figure it out adequately). I was trying to equate the two drivers an octave out of band prior to L-R crossover.
How do you achieve this?
well... I tried that. And you really have to be careful, because any automated process, can't give you any better result, than the data that you put in. So you might end up with quite a few weird sounding results, before you feel that it sounds somewhat good enough, to worth the effort, compared to IIR - IMO.Ultimately, if you get the FIR bug, automated FIR generators that make FIR files to match target curves are the way to go.
Essentially, matching response to a target curve does the same thing as flatten first, and add xover....only without so much work !
I would say that the benefit of FIR, is the precision, compared to IIR. But at lower frequencies, it really ain't worth the hassle - IMO.Heh, I can say I did precisely as you suggest…except I failed in any attempt to use FIR…2x4 hd has limited available taps, and I was trying to align under 500 hz between twin 15” woofers and a fullrange. as I recall there are only 1200 taps available per channel…and I remember convincing myself I can’t get there from here.
Hi, just making sure i understand...Heh, I can say I did precisely as you suggest…except I failed in any attempt to use FIR…2x4 hd has limited available taps, and I was trying to align under 500 hz between twin 15” woofers and a fullrange. as I recall there are only 1200 taps available per channel…and I remember convincing myself I can’t get there from here.
Haha...ain't that the truth!!!!well... I tried that. And you really have to be careful, because any automated process, can't give you any better result, than the data that you put in. So you might end up with quite a few weird sounding results, before you feel that it sounds somewhat good enough, to worth the effort, compared to IIR - IMO.
so-called "Time alignment" actually turned out to be critical in two way loudspeakers in the early days of the "talkies".
I was being facetious. Those Western Electric horns were one of the reasons the Shearer horn research began. Their time delay between drivers must have been measured in minutes.so-called "Time alignment" actually turned out to be critical in two way loudspeakers in the early days of the "talkies".
I'll bet you knew that already.
I think this was already mentioned before in this thread.
View attachment 207050
source: https://worldradiohistory.com/Archive-All-Audio/Archive-Audio/70s/Audio-1977-08.pdf
Hilliard reference cited above (Ref. 1) J. Hilliard, "Historical Review of Horns Used for Audience Type Sound Reproduction" J.A.S.A. 59 (1), 1 (Jan. 1976).
Industry Pioneers #18: Dr. John K. Hilliard, The Standard Of Motion-Picture Sound
Hilliard set Hollywood's audio standards, designed some of the earliest cinema speakers, and made innovations in microphone technology.www.soundandcommunications.com
tap-tap!I was being facetious. Those Western Electric horns were one of the reasons the Shearer horn research began. Their time delay between drivers must have been measured in minutes.
Using 16th order / brickwall filters to improve driver alignment and phase brings up the question of which is more audible phase issues or filter ringing neither of which are well studied as far as I can tell.
I would say that the benefit of FIR, is the precision, compared to IIR. But at lower frequencies, it really ain't worth the hassle - IMO.
...
Yeppers, back when passive xovers ruled, stuff by Vandersteen, Theil, and Dunlavy among others, helped demonstrate the value of phase-correct, time-aligned designs.RichardVandersteen's floor standing speakers attempt both at time-alignment and "phase-correct designs" of the drivers.
A tough act!
Hi, no clue what you mean...From a dispersion perspective, that will yield a massive change as one moves in frequency through that region.
Hi, no clue what you mean...
massive change in what? thru what region?
I just look at polar responses. On -axis vs off-axis measurements.
Ime, High order lin phase xovers have helped definitely those converge, with less variance
Whatcha mean? thx
When one is using multiple subs, say, 3 or more for multiple seating positions or rows in a home theater, does perfect (or near-perfect) linear phase down to the bass even make much practical sense at all?
I expect not. perfect impulse/step will occur only to a specific spot ime.Has anyone actually achieved a perfect looking step response in all seats in a home theater? I remember Geddes asking how one's supposed to even go about getting it "perfect" (linear phase and ideal-looking step response below Schroeder) in his dedicated home theater/listening room.
Gotcha. Thx.I mean a 12” woofer will have a certain horizontal radiation at 490 Hz.
If a 3” MR is 100% at 510 Hz, then the dispersion angle will do a 4:1 jump over a small frequency range.
This is true when phase tracks, and if the phase is being wild, then it can be worse again.
The opposite example would be a wideband driver with no crossover… and the horizontal and vertical dipersion will slowly narrow as the frequency increases.