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Multi-Way Conventional loudspeakers with crossovers

Powered speakers _ are they phase coherent by design ?
Powered speakers _ are they phase coherent by design ?
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Old 9th September 2019, 10:10 AM   #11
AllenB is offline AllenB  Australia
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Quote:
My ideal speaker has a fantastic 3D soundstage and great voice reproduction. That is what i am looking for.
I don't think phase is your issue.
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Old 9th September 2019, 10:30 AM   #12
ginetto61 is offline ginetto61  Italy
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Originally Posted by AllenB View Post
I don't think phase is your issue.
Hi ! i agree that the listening room comes first ... but i understand speakers come second in order to get great soundstage (assuming that the soundstage has been well captured in the recordings of course). Let's say that if there is in the recording i would like to get it.
Moreover i have the feeling that to design a phase coherent crossover is quite challenging. Just a feeling.
That they are more the exception than the rule ?
This could be the reason why many audio lovers prefer wideband single drivers ?
and despite of all their other limits
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Thank you very much indeed
Kind regards,
gino
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Old 9th September 2019, 10:49 AM   #13
phase_accurate is offline phase_accurate
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There are some ways to build transient-perfect (=phase-coherent) or at least transient-improved crossovers that can't be done easily in a passive way.

I once did a quite simple active crossover for a wideband Driver plus woofer topology which is not that difficult to implement and that is almost transient perfect. For ages I wanted to do that one again with cheaper drivers buit I didn't find any time for it so far.

Regards

Charles
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Old 9th September 2019, 10:55 AM   #14
sangram is offline sangram  India
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Originally Posted by ginetto61 View Post
Moreover i have the feeling that to design a phase coherent crossover is quite challenging. Just a feeling.
That they are more the exception than the rule ?
This could be the reason why many audio lovers prefer wideband single drivers ?
and despite of all their other limits
It's not particularly challenging to design a phase coherent speaker on one axis.

The moment you throw in a real room with different arrival times for the same frequencies, that you begin to face a problem.

For any two driver combination excepting coaxials and horns, actually being phase coherent at listening position in a real room is quite difficult, regardless of performance in anechoic conditions.

Single driver speakers are not immune to room issues either so suffer from phase errors in real world situations anyway.
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Old 9th September 2019, 11:05 AM   #15
Draki is offline Draki  Macedonia
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Originally Posted by ginetto61 View Post

leaving aside xover less speakers which would be an example of multi-ways phase-coherent speaker?
This is a random but very telling example (of a phase coherent passive, non-DSP multi-way system)

Vandersteen Audio Treo loudspeaker Measurements | Stereophile.com
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Old 9th September 2019, 11:24 AM   #16
phase_accurate is offline phase_accurate
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Leaving aside the discussion wether transient-perfect is needed at all, there is always the discussion about loosing transient-accuracy off axis. I would say that if it matters at all it will definitely only matter on axis anyway, because only the first wavefront is used to localise a sound source by our auditory system.

OTOH I agree that some methods used for achieving transient-improved
response are detrimental to the off-axis amplitide response. How much that matters depends on the actual listening situation.

Regards

Charles
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Old 9th September 2019, 11:59 AM   #17
sangram is offline sangram  India
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I'll try and illustrate using a theoretical simulation. I do not like the construction complexity of tilted or stepped baffles. When I desire time alignment I will put tweeter below woofer or 'fix it' in the crossover.

I have attached two pictures, each is for a 'phase coherent' system with drivers tracking phase reasonably well (for a multi-driver system on a flat baffle). All FRD/ZMA files were traced from manufacturer's IB measurements, and the bump at the low end is to compensate for baffle step. Both driver sets are totally different, and time offsets have been manually entered.

In picture 1, notice the two drivers track phase very accurately right upto the point the the woofer starts going crazy due to breakup. Though in FR terms it is contributing very little to the output, this is not going be winning any awards for good performance. It will be a little rough up top.

In picture 2, you will see the drivers tracking much better all the way till 40-45dB of attenuation, with very little phase difference till we get past 9k. This will be a better product (provided drivers have low distortion etc and if I manage to get the time to actually finish the crossover and buy parts).

IOW, phase coherence alone does not make a speaker sound good.
Attached Images
File Type: png Clipboard01.png (134.5 KB, 183 views)
File Type: png Clipboard02.png (167.9 KB, 189 views)
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Old 9th September 2019, 12:50 PM   #18
AllenB is offline AllenB  Australia
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Originally Posted by ginetto61 View Post
But let's take a full range single driver no xover speaker as an example of 100% phase coherent speaker.
Show me any driver with no phase variation. A crossover is not the only thing to change phase.

A crossover can even improve phase.
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Old 9th September 2019, 12:55 PM   #19
sangram is offline sangram  India
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Originally Posted by AllenB View Post
Show me any driver with no phase variation. A crossover is not the only thing to change phase.

A crossover can even improve phase.
QFT.

The assumption is that single drivers have 100% phase coherence.

The truth is that dynamic loudspeakers by their very design are not phase coherent devices. It is impossible to have any device/component that creates a delay between current and voltage to be 'phase perfect', if that were a thing.
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Old 9th September 2019, 12:57 PM   #20
mark100 is online now mark100  United States
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Hi, adding to what others have said about the use, or rather miss-use, of the term phase often heard in home audio discussions...
'Polarity' is the preferred term for getting + and - in sync together.

If I may define a powered speaker as a multi-way, where each driver section is actively driven by a separate amplifier channel, then I would say any good design has been built to be phase coherent. It's silly not to.

In the prosound world, phase coherency has become a clearly stated objective, often ranking with frequency response, pattern control, and SPL.

Meyersound has stressed phase accuracy for well over 20 years. Today, every new design touts phase coherency...here's a couple of examples from yamaha and rcf ........ DZR / DXS XLF Series - DZR Features - Speakers - Professional Audio - Products - Yamaha - UK and Ireland
FiRPHASE - RCF


It's audible and can only help ime/imo, ...whether in a good room, a bad room, or outdoors (best place to evaluate)
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