Hi ! i read often about phase in speakers and the importance that a speaker is phase coeherent, expecially for a good rendering of the virtual soundstage that i love immensely
I have at hand a Dayton Audio DATS v3 Is it possible to check in some way if a speaker is phase coeherent with this device ?
could you please link a phase graph of a speaker that is indeed phase coeherent and i can keep as reference please ?
this phase issue has always been difficult for me to understand
Thank you very much
Have a nice day before it is too late
I have at hand a Dayton Audio DATS v3 Is it possible to check in some way if a speaker is phase coeherent with this device ?
could you please link a phase graph of a speaker that is indeed phase coeherent and i can keep as reference please ?
this phase issue has always been difficult for me to understand
Thank you very much
Have a nice day before it is too late
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Hi please excuse me if i reply to myself I skipped on a due diligence However I think i have found a perfect reference ?
https://www.stereophile.com/images/719MLRSfig1.jpg
the phase vs Hz cuve is almost completely flat Impressive
This i can see with the DATS for sure
another good but old one
https://www.stereophile.com/images/719MLRSfig1.jpg
the phase vs Hz cuve is almost completely flat Impressive
This i can see with the DATS for sure
another good but old one
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Phase coherence does not mean good sound. It means phase of two sources are working together.
It would normally refer to phase of the measured sound pressure responses, not of their impedances.
It would normally refer to phase of the measured sound pressure responses, not of their impedances.
Hi thanks a lot Let me elaborate a little Some multiways speakers sound like a single driver speaker I guess this is what they mean for coherence
is this not a good think to get ? i have seen for example that Thiel and Dunlavy speakers show phase vs Hz plots quite flat and fwiu this is a design requirements i have no chance to understand how to design a phase flat speaker but i can measure that Is of no importance ?
some speakers show phase curves going up and down +/-90 degrees
i see I wonder if this can be measured as well
Regarding good sound i understand that is very difficult to correlate it with measurements
Like the sound of a certain cone material
I mean Al and paper cones sound extremely different But it is impossible to show this with measurements Only by listening Am i right ?
I did not say it was a bad thing and I did not say it was a good thing. I just said that coherence means being in phase.
Imaging is significantly related to other in room behaviours, overall phase is not the key. Sometimes your speaker will be in phase for good imaging and sometimes it will not be in phase for good imaging.
You can show resonances and breakup artifacts. These can be measured. You might recall these are mostly at higher frequencies where you should have already crossed..
Coherence is usually in reference to "acoustic phase", not "electrical phase".
Here's a link to a post that shows acoustic phase, among other things.
https://www.diyaudio.com/community/threads/radian-5208c-coaxial-project.283818/post-6707453
Good acoustic alignment between drivers contributes to coherence. "Minimum Phase" is needed for each driver to see how closely their phases are aligned. Under 30 degrees is often considered good, less than 10 degrees is excellent. Room acoustics play a big role in imaging, as noted by @AllenB.
Here's a link to a post that shows acoustic phase, among other things.
https://www.diyaudio.com/community/threads/radian-5208c-coaxial-project.283818/post-6707453
Good acoustic alignment between drivers contributes to coherence. "Minimum Phase" is needed for each driver to see how closely their phases are aligned. Under 30 degrees is often considered good, less than 10 degrees is excellent. Room acoustics play a big role in imaging, as noted by @AllenB.
Hi thank you very much I have never seen this graph in the lab reports I cannot understand the graphs at all
I wonder if there is some explanation for dummies somewhere But it is too difficult topic
I wonder if there is some explanation for dummies somewhere But it is too difficult topic
So if you decided that phase should track to a fixed separation of 60 degrees, it would be good at between 30-90 degrees and better at 50-70 degrees?
Not sure what fixed separation is. My description of phase alignment refers to relative phase difference between two drivers summing through their crossover region. With perfect phase alignment, the two would overlay each other exactly. It's usually not a trivial exercise to get there.
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Here's a plot of actual spl and acoustic phase for a recent budget 2-way speaker project.
The main part of the crossover region is between 1300 Hz and 4000 Hz, centered at about 2300 Hz.
This is where the 2 drivers contribute to the total summation. Below that, the woofer dominates. Above that, the tweeter dominates.
The phase separation is not fixed, but the alignments in that region are within about 30 degrees of each other.
Optionally, you could say that the average phase separation in that region is 0 deg, with a +/-15-degree variation.
The sound is not fantastic, but it's actually not bad, considering the total budget was under $70 (US) for the pair.
Good enough for a garage speaker. 😉
The main part of the crossover region is between 1300 Hz and 4000 Hz, centered at about 2300 Hz.
This is where the 2 drivers contribute to the total summation. Below that, the woofer dominates. Above that, the tweeter dominates.
The phase separation is not fixed, but the alignments in that region are within about 30 degrees of each other.
Optionally, you could say that the average phase separation in that region is 0 deg, with a +/-15-degree variation.
The sound is not fantastic, but it's actually not bad, considering the total budget was under $70 (US) for the pair.
Good enough for a garage speaker. 😉
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Pages 3-5 at this link are a decent overview if the topics are unfamiliar. Step response is where some of this behavior shows up in typical reviews.
https://www.stereophile.com/content/measuring-loudspeakers-part-two-page-3
Hi thank you sincerely for the link
While it is absolutely clear to me the concept of time coeherency or alignment when they start to speak of phase i do not understand anything
Phase is a concept to difficult for me to understand
What i know is that a correct phase is important for a good 3d soundstage rendition
Now i have learned that what must be measured is the acoustic and not the electrical phase This complicates the task
Moreover i understand that this one below is the acoustic phase plot of a perfectly acoustic phase coeherent speaker
i wonder which one actually is Mystery
While it is absolutely clear to me the concept of time coeherency or alignment when they start to speak of phase i do not understand anything
Phase is a concept to difficult for me to understand
What i know is that a correct phase is important for a good 3d soundstage rendition
Now i have learned that what must be measured is the acoustic and not the electrical phase This complicates the task
Moreover i understand that this one below is the acoustic phase plot of a perfectly acoustic phase coeherent speaker
i wonder which one actually is Mystery
Hi thanks but now i surrender Then what makes a speaker a soundstage champion ?
in the same room different speakers behave quite differently regarding soundstage
Most speakers tend to sound flat two dimensional with no soundstage depth That is exactly the contrary of what stereo is about
When 3d effect is very well rendered it has something of magic
in the same room different speakers behave quite differently regarding soundstage
Most speakers tend to sound flat two dimensional with no soundstage depth That is exactly the contrary of what stereo is about
When 3d effect is very well rendered it has something of magic
Hi, the magic happens inside your head, in the auditory system. For the magic to happen, the playback system needs to be aligned in multiple fronts. For example, even if you had "ideal speakers", what ever those are, you must still have good positioning of the system. Even if you had good positioning of the system, but have yourself in not "optimal" area this will ruin it, you with your auditory system are part of the playback system, huge part of eventual perception of sound in the room. Beyond this, there might not be optimal sound never with some particular bad acoustics in room with combination of some speakers.
And to my knowledge it's just how your auditory system is able to lock on to the phantom center, get fooled it's a real sound source. Brain locks in when original harmonics of original sounds are preserved well enough they make huge amplitude peaks superimposing every fundamental cycle, making the sound source stick out above all sounds around us, which the auditory system now pays attention to because in nature this kind of sound source is physically close to us so auditory system would elevate your attention to it, because it's very likely something important for survival. Conversely, not important sounds do not get your attention, which means if the sound of your stereo is noise to your auditory system you won't perceive it well, your auditory system ignores it as noise, unimportant.
Apparently main mechanism is that harmonics do not superimpose as big peak if phase is ruined by the speaker (too much group delay) for example, and the noise part could be way loud if your room has too loud early reflections or edge diffraction, noise in general. So, make sure "noise" is down, and make sure original harmonics are preserved well and you should have it to maximize signal to noise ratio of the direct sound basically, so your brain can lock in, consider sound of your system important and pay attention. Easiest thing is to shorten listening distance (listening triangle size) to increase ratio of direct / reflected sound. Also make sure Left and Right speakers match well enough, are equidistant to you and with same toe-in so with ~same frequency response to make sure the phantom center is as solid as possible, and are without too bad edge diffraction issues and room early reflections to keep the noise part down further helping this stuff.
See David Griesinger lectures / papers on auditory proximity and limit of localization distance.
And to my knowledge it's just how your auditory system is able to lock on to the phantom center, get fooled it's a real sound source. Brain locks in when original harmonics of original sounds are preserved well enough they make huge amplitude peaks superimposing every fundamental cycle, making the sound source stick out above all sounds around us, which the auditory system now pays attention to because in nature this kind of sound source is physically close to us so auditory system would elevate your attention to it, because it's very likely something important for survival. Conversely, not important sounds do not get your attention, which means if the sound of your stereo is noise to your auditory system you won't perceive it well, your auditory system ignores it as noise, unimportant.
Apparently main mechanism is that harmonics do not superimpose as big peak if phase is ruined by the speaker (too much group delay) for example, and the noise part could be way loud if your room has too loud early reflections or edge diffraction, noise in general. So, make sure "noise" is down, and make sure original harmonics are preserved well and you should have it to maximize signal to noise ratio of the direct sound basically, so your brain can lock in, consider sound of your system important and pay attention. Easiest thing is to shorten listening distance (listening triangle size) to increase ratio of direct / reflected sound. Also make sure Left and Right speakers match well enough, are equidistant to you and with same toe-in so with ~same frequency response to make sure the phantom center is as solid as possible, and are without too bad edge diffraction issues and room early reflections to keep the noise part down further helping this stuff.
See David Griesinger lectures / papers on auditory proximity and limit of localization distance.
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With many speakers, there tends to be some tradeoff between image specificity and soundstage depth. You run into this with loudspeaker dispersion (narrow vs wide), room placement, and room treatment.
How much of each thing you like comes down to personal preference. As the Stereophile link mentions, most speakers are not time and phase coherent, and many listeners can't tell the difference. So it's not like it's the only answer to achieving good sound. It's typically viewed as a "nice to have," though obviously some manufacturers think it's important for their designs.
https://www.stereophile.com/content/measuring-loudspeakers-part-two-page-4
"One school of thought holds that it is very important to perceived quality; another, which includes almost all loudspeaker engineers, finds it unimportant. Floyd Toole, now with Harman International but then with Canada's National Research Council, in his summary of research at the NRC into loudspeaker performance that is described in two classic 1986 papers [32, 33], concluded thusly: 'The advocates of accurate waveform reproduction, implying both accurate amplitude and phase responses, are in a particularly awkward situation. In spite of the considerable engineering appeal of this concept, practical tests have yielded little evidence of listener sensitivity to this factor...the limited results lend support for the popular view that the effects of phase are clearly subordinate to amplitude response.'
This is also my view. Of the 350 or so loudspeakers I have measured, there is no correlation between whether or not they are time-coherent and whether or not they are recommended by a Stereophile reviewer. However, I feel that if other factors have been optimized—on-axis response, off-axis dispersion, absence of resonance-related problems, and good linearity—like a little bit of chicken soup, time coherence (hence minimal acoustic phase error) cannot hurt. In my admittedly anecdotal experience, a speaker that is time-coherent (on the listening axis) does have a small edge when it comes to presenting a stereo soundstage, in terms of image focus and image depth. But time coherence does not compensate for coloration, poor presentation of instrumental timbres, a perverse frequency balance, or high levels of nonlinear distortion.
In 1990, Rodney Greenfield and Malcolm Omar Hawksford [34] used DSP-based digital filters to try to separate the audible effects of a loudspeaker's phase error from its amplitude response error. The point was made that a semi-reverberant environment will tend to mask phase effects. In addition, when typical recordings are played, which may have undergone many phase-altering stages during production, the audibility of phase differences becomes moot: 'one is simply detecting a change in phase distortion and not a correction of it and as such preferences would most likely be personal.' Nevertheless, the authors "very tentatively" concluded that equalizing a loudspeaker's excess phase error modified listeners' perception of the apparent soundstage."
If you aren't comparing a phase coherent to non-phase-coherent speaker in this scenario, that should tell you something also.
Good matching of frequency response between left and right speakers and even dispersion patterns are generally considered beneficial.
and this is clear My brain uses the signals coming out from the speakers to create a virtual soundstage No problem for this
yes and no I perceived a better soundstage once just changing the integrated and this impressed me a lot
I have always thought that amps do not soundstage Speakers do
But in that case i was listening two different integrated One soundstaged much better that the other All other things kept equal
thank you very much again and lets see if i have understood correctly I have to breakdown the complex advice
More than equipment what provides a better sensation of the virtual soundstage is how speakers are placed in the listening room and their interactions with the room boundaries ? so even a soundstage champ speaker placed bladly will fail to provide the soundstage is capable of ?
i am afraid i can do much with my auditory system aside cleaning y ears Actually i am losing all high freqs above 13k these days
thanks again this is very important usually i get fascinated by the things i do not understand and phase is for sure one of those
i was clearly overrating this phase accuracy thing Amplitude i can understand better and i can also measure it Good One issue closed
the only thing that i could measure is the frequency balance if you mean the frequency response
nonlinear distorsion aside the other parameters seem to me impossibile to measure I guess they can only be evaluated by listening ?
is this the reason why FR in an anechoic room looks worse i.e. less linear than in a normal listening room ? sometime the effect or room boundaries is very impressive on global linearity
much more complex of what i thought Tend even speakers with a irregular acoustic phase response can be great at throwing in the right conditions a great soundstage in the room ? then i will stop worrying about phase completely One problem less