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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 4th September 2019, 03:24 PM   #1
ginetto61 is offline ginetto61  Italy
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Default Powered speakers _ are they phase coherent by design ?

Hi ! lately i have become obsessed by this phase coherency thing.
Because i do not understand it.
My questions are:
- is phase coherency really important in a speaker ?
- is a powered speaker coherent by design ?
Thanks a lot for any kind advice.
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Thank you very much indeed
Kind regards,
gino
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Old 4th September 2019, 06:13 PM   #2
planet10 is offline planet10  Canada
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Powered speakers _ are they phase coherent by design ?
Quote:
- is phase coherency really important in a speaker ?
Jury is still out. The growing FR segment of the market might be an indicator that it is (no XO). But so much has to do with the nature of your hearing, and how phase coherent the media is.

Quote:
- is a powered speaker coherent by design ?
No. They are usually just as bad as most speakers.

dave
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Old 4th September 2019, 11:38 PM   #3
Enzo is offline Enzo  United States
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A powered speaker is just a speaker. It just happens to have the amplifier in the same box instead of sitting next to it. Any phase issues between woofer and tweeter would exist either way.
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Old 5th September 2019, 07:42 AM   #4
ginetto61 is offline ginetto61  Italy
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hi thanks a lot for the very kind and helpful advice
First of all please let me explain a little the origin of my doubts
I was listening to the old cd test depicted here below

Click the image to open in full size.

there is a test voice track with a signal first in phase and then out of phase
When in phase the voice is dead center .. when out of phase the voice is difficult to locate in space not focused
I guess that when the effect is very strong the speakers should be more phase coherent ? because they allow to discriminate better the situation in phase from out of phase ?

leaving aside xover less speakers which would be an example of multi-ways phase-coherent speaker?
Maybe this one is almost phase coherent ?

https://www.stereophile.com/images/a...107DC1fig8.jpg

Click the image to open in full size.

as you can understand i am as much confused as intrigued
For me 3D soundstage is everything
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Kind regards,
gino

Last edited by ginetto61; 5th September 2019 at 08:01 AM.
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Old 5th September 2019, 10:58 AM   #5
DF96 is offline DF96  England
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The effect of swapping phase on one channel would be clear even with really bad speakers. All it requires is that the two speakers are identical, not that they are good.

May you are confusing interchannel phase problems with frequency-dependent phase problems?
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Old 5th September 2019, 12:07 PM   #6
ginetto61 is offline ginetto61  Italy
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Quote:
Originally Posted by DF96 View Post
The effect of swapping phase on one channel would be clear even with really bad speakers. All it requires is that the two speakers are identical, not that they are good.
May you are confusing interchannel phase problems with frequency-dependent phase problems?
Hi and yes probably i am confusing things because phase is a very difficult concept for me to understand. I can understand freq response, distortion, dispersion but phase i do not understand.
But let's take a full range single driver no xover speaker as an example of 100% phase coherent speaker.
I have listened to some of the kind like the Quad esl 63 and Magneplanar ... do they really provide a "coherence" in sound that is very difficult to achieve instead with a standard multiways speaker or it is just a sensation ?
I mean there must be some reasons why wideband drivers have become so popular lately. I know that they have limits in freq range, dispersion and distortion ... but what i could get in return ? what are their peculiar characteristics that are impossible to match with a more traditional design ? are they the way to go ?
My ideal speaker has a fantastic 3D soundstage and great voice reproduction. That is what i am looking for.
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Kind regards,
gino

Last edited by ginetto61; 5th September 2019 at 12:23 PM.
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Old 5th September 2019, 05:41 PM   #7
planet10 is offline planet10  Canada
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Powered speakers _ are they phase coherent by design ?
Quote:
Originally Posted by ginetto61 View Post
...there is a test voice track with a signal first in phase and then out of phase
When in phase the voice is dead center .. when out of phase the voice is difficult to locate in space not focused
I guess that when the effect is very strong the speakers should be more phase coherent ? because they allow to discriminate better the situation in phase from out of phase ?
i would guess that that track shows you whether 1 speaker is out of phase with the other, nothing to do with the phase performance of the speaker.

Having the speakers connected in the same phase is very important.

dave
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Old 5th September 2019, 05:43 PM   #8
planet10 is offline planet10  Canada
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Powered speakers _ are they phase coherent by design ?
Quote:
Originally Posted by ginetto61 View Post
… let's take a full range single driver no xover speaker as an example of 100% phase coherent speaker.
I have listened to some of the kind like the Quad esl 63 and Magneplanar …
Not good examples, each of those is a 2-way.

dave
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Old 5th September 2019, 06:10 PM   #9
Enzo is offline Enzo  United States
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Planet said it first, but I think you are confusing two terms. IN a stereo setup, the two speakers need to be in phase with each other, meaning they move forward or back at the same time. When you ask if a speaker is phase coherent, what we generally mean is within one speaker, are the drivers (woofer, tweeter) lined up in the box so the sound wavefronts from all drivers arrive at the listener together. In other words, if the tweeter is four inches closer to the listener than the woofer is, the sound from each arrives slightly different in time.

SO your single driver speaker would be phase coherent only in the sense that all the frequencies come from the same driver The single driver box could be wired in or out of phase with its mate, but that is separate.

Any speaker will reveal phasing if you reverse the wires to ONE side of the pair.

Within a multi-driver cabinet, it is also important for all the drivers to be in phase with one another. That is not the same as phase coherent. By their nature, crossover circuits can alter the phase of a signal, so it often is not as simple as wiring all the + terminals together.

Your description was classic. In phase speakers make the sound seem to come from the center between the speakers. Out of phase speakers make the sound seem to come from somewhere around you. Also out of phase tends to cancel the bottom end substantially.
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Old 9th September 2019, 08:55 AM   #10
ginetto61 is offline ginetto61  Italy
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Quote:
Originally Posted by Enzo View Post
Planet said it first, but I think you are confusing two terms.
IN a stereo setup, the two speakers need to be in phase with each other, meaning they move forward or back at the same time.
Hi ! that is clear to me. Red with red and black with black always.
I had an old pair of speakers without the red and black marks. Then a friend told me to check with a 1.5V battery ... when the + of the battery and of the speaker are connected the woofer comes forward.

Quote:
When you ask if a speaker is phase coherent, what we generally mean is within one speaker, are the drivers (woofer, tweeter) lined up in the box so the sound wavefronts from all drivers arrive at the listener together. In other words, if the tweeter is four inches closer to the listener than the woofer is, the sound from each arrives slightly different in time. SO your single driver speaker would be phase coherent only in the sense that all the frequencies come from the same driver The single driver box could be wired in or out of phase with its mate, but that is separate.
Quote:
Ok i understand. But this i would call time coherence ? i have seen many speakers with drivers mounted in a way that the center of emissions of the different drivers are on a same plane like the old B6W dm6 and many others.

Quote:
Any speaker will reveal phasing if you reverse the wires to ONE side of the pair.
Within a multi-driver cabinet, it is also important for all the drivers to be in phase with one another. That is not the same as phase coherent. By their nature, crossover circuits can alter the phase of a signal, so it often is not as simple as wiring all the + terminals together.
Your description was classic. In phase speakers make the sound seem to come from the center between the speakers. Out of phase speakers make the sound seem to come from somewhere around you. Also out of phase tends to cancel the bottom end substantially.
Thank you very much indeed. I think i have identified better the problem with your help.
I should have asked about phase coherent crossovers ?
is there any link treating this precise topic ?
And i also wonder if active xovers are easier to me built phase coherent than passive ones.
Actually i do not understand why not all commercial crossovers are phase coherent ... is it so difficult to design one ?
Thanks a lot again,
Kind regards
__________________
Thank you very much indeed
Kind regards,
gino

Last edited by ginetto61; 9th September 2019 at 09:08 AM.
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