These are not linear-phase loudspeakers, maybe they have good phase tracking between the drivers (like any decent speaker with Linkwitz-Riley crossover) but their phase response wraps, so not linear.
It's not easy to create a linear-phase loudspeaker with passive crossover.
Check this, almost linear phase, passive 2-way:
Simple Passive Harsch XO Using PTT6.5 and RS28F in a Waveguide
It's not easy to create a linear-phase loudspeaker with passive crossover.
Check this, almost linear phase, passive 2-way:
Simple Passive Harsch XO Using PTT6.5 and RS28F in a Waveguide
The Harsch crossover does have considerable problems off axis, which is more of a concern than the phase thing.
Can you please describe coherence in this case..
The Kairos aren't linear phase, but they don't use standard Linkwitz-Riley crossovers either. Here's a couple of lines from Jeff's write-up (LINK):
"Crossover: 1.8 kHz Asymmetrical 1st Order / 2nd Order slopes at crossover point
Time Domain: Time aligned first arrival impulse
Phase Response: Minimum Phase within 30 degrees error through crossover region"
See the attachment (also taken from the write-up) for the measured system FR and phase. Note that this is the sealed response with the port plugged. I'd imagine you would see phase wrap with port open. YMMV.
Attachments
I'd like to get linear phase 100hz-10Khz. So the "Kairos" seem to do that according to the graph attached in this topic. For near field monitoring (this application), the room reflections would be minimized and I think a 2-way with relatively linear phase in the 100hz-10Khz region would be of great benefit.
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While there are linear phase 2-ways that have been designed for near-field monitoring,
Earthworks Sigma 6.2 loudspeaker | Stereophile.com
Earthworks Sigma 6.2 Monitors
In my experience the driver center-to-center spacing and crossover frequency should be carefully considered to avoid excessive lobing and narrowing of the service area.
Although I am not aware of any 3-way linear phase kits, a 3-way design will make it easier to address the driver spacing and crossover frequency interactions.
Pushing the limits of small speakers - The Reference Mini build thread
The above thread is about an active rather than passive design, nonetheless lists many of the concepts and issues that should be addressed to make a linear phase speaker design function optimally, whether the crossover is active or passive.
hth, jonathan
Earthworks Sigma 6.2 loudspeaker | Stereophile.com
Earthworks Sigma 6.2 Monitors
In my experience the driver center-to-center spacing and crossover frequency should be carefully considered to avoid excessive lobing and narrowing of the service area.
Although I am not aware of any 3-way linear phase kits, a 3-way design will make it easier to address the driver spacing and crossover frequency interactions.
Pushing the limits of small speakers - The Reference Mini build thread
The above thread is about an active rather than passive design, nonetheless lists many of the concepts and issues that should be addressed to make a linear phase speaker design function optimally, whether the crossover is active or passive.
hth, jonathan
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With regard to near field.
Sound Reproduction, Toole Chapter 4.8.1
Researchers had to go to a lot of trouble to make it audible. When they did, there was no clear preference, "because two ears and a brain seem not to care."
I think DIYers can get caught up in the physics of sound while ignoring the psychology of sound. Our brains create and perceive sound. If you want to see examples of how sound is not entirely dependent on physics watch this YouTube video on audio illusions. Will This Trick Your Ears? (Audio Illusions) - YouTube
Having said that, you might have primed yourself to believe phase coherent speakers sound better than phase incoherent speakers. Consequently, if someone told you the speaker was phase coherent -- even if it wasn't -- it might actually sound better to you. That's not a bad thing. You tricked yourself into thinking something sounds better and you derive greater satisfaction as a result. It's not too different from building a visually beautiful speaker and thinking it sounds better because the finished maple sounds more natural than synthetic plastic. Or buying a set of drivers recommended by people who say they are "detailed and musical in the mids" and then believing the drivers sound detailed and musical in the mids.
If your brain is primed to believe something is true it might be true for you because our brains create audio illusions.
That's neat. On the one hand Toole says you can't hear it and on the other Linkwitz says you can. I think that's good because Linkwitz supplies a foundation to prime your brain so you think you hear something, e.g. a much wider and deeper soundstage.
It's like the auditory illusion video I posted above. You might hear a structure jumping up and down even though there's no audio. Well, if you prime your brain to believe linear phase produces a wider and deeper soundstage you will hear the illusion of a wider and deeper soundstage.
However, I wonder if you could prime your brain to believe yellow colored speakers produce a wider and deeper soundstage similar to chromesthesia. Or moving your speakers further apart, etc. I know when some people listen to Don Keele's curved CBT arrays they hear audio illusions related to the visual shape of the array.
And the reverse is probably true. I'm primed by Toole to not hear a difference so I probably won't hear a difference.
It's like the auditory illusion video I posted above. You might hear a structure jumping up and down even though there's no audio. Well, if you prime your brain to believe linear phase produces a wider and deeper soundstage you will hear the illusion of a wider and deeper soundstage.
However, I wonder if you could prime your brain to believe yellow colored speakers produce a wider and deeper soundstage similar to chromesthesia. Or moving your speakers further apart, etc. I know when some people listen to Don Keele's curved CBT arrays they hear audio illusions related to the visual shape of the array.
And the reverse is probably true. I'm primed by Toole to not hear a difference so I probably won't hear a difference.
Linear-Phase speakers reproduce superior square wave response and impulse response.
"Measurements with square wave signals should be included as standard testing procedures in order to be able to detect errors with sound quality and spatial imaging in loudspeaker systems. Many technical and acoustical faults can not be registered with SPL or frequency measurements, although they have induced significant irregularities into the relevant audio signal waveform."
"Measurements with square wave signals should be included as standard testing procedures in order to be able to detect errors with sound quality and spatial imaging in loudspeaker systems. Many technical and acoustical faults can not be registered with SPL or frequency measurements, although they have induced significant irregularities into the relevant audio signal waveform."
That "wider and deeper soundstage" of linear-phase designs may fail to manifest itself if cabinet edges are left in a state that causes diffractions / reflections, if the design doesn't consider lobing errors, or if sharp changes in directivity are allowed.
It is almost certain that the drivers reproducing the upper frequencies will require some form of physical setback for time alignment, which is very likely to introduce additional cabinet edges and sources of diffraction (unless all-pass delay networks are used).
And if the crossover frequencies and driver spacings are not carefully considered, lobing errors and abrupt changes in directivity (which will cause the direct and reflected sounds to have different spectral balances) are practically guaranteed.
Generally linear-phase speakers are less tolerant of design or construction techniques that would pass muster on conventional speakers.
Reading researchers' publications doesn't always clarify how thorough (or not) the researchers were in their design or testing methodology.
It is almost certain that the drivers reproducing the upper frequencies will require some form of physical setback for time alignment, which is very likely to introduce additional cabinet edges and sources of diffraction (unless all-pass delay networks are used).
And if the crossover frequencies and driver spacings are not carefully considered, lobing errors and abrupt changes in directivity (which will cause the direct and reflected sounds to have different spectral balances) are practically guaranteed.
Generally linear-phase speakers are less tolerant of design or construction techniques that would pass muster on conventional speakers.
Reading researchers' publications doesn't always clarify how thorough (or not) the researchers were in their design or testing methodology.
In Toole's book he uses the word "square" 26 times but never mentions measurements with square wave signals. Mostly, he talks about the inverse-square law. (3rd edition published in 2018)
The sense I get from Toole's book is that some things are important and others aren't. So, linear phase -- if it was audible -- would get overwhelmed by changing seating position or turning on a fan. Further, even if you sat in an anechoic chamber you might not even prefer whatever it is linear phase might do. In contrast, Toole says room reflections are preferred, yet room reflections interfere with phase. My conclusion from Toole's book would be that we should pay attention to getting good room reflections (with all the associated linear phase disruptions) and don't chase after linear phase because the only way to achieve it is to destroy your room reflections.
The caveat, of course, is that belief is a heck of a drug. Especially when the goal is an illusion such as differences in sound stage size. We know our visual perception can dominate our ears. If I wanted an audio illusion and there wasn't a clear proven way to do it with physics I'd trick my brain with visual cues.
The sense I get from Toole's book is that some things are important and others aren't. So, linear phase -- if it was audible -- would get overwhelmed by changing seating position or turning on a fan. Further, even if you sat in an anechoic chamber you might not even prefer whatever it is linear phase might do. In contrast, Toole says room reflections are preferred, yet room reflections interfere with phase. My conclusion from Toole's book would be that we should pay attention to getting good room reflections (with all the associated linear phase disruptions) and don't chase after linear phase because the only way to achieve it is to destroy your room reflections.
The caveat, of course, is that belief is a heck of a drug. Especially when the goal is an illusion such as differences in sound stage size. We know our visual perception can dominate our ears. If I wanted an audio illusion and there wasn't a clear proven way to do it with physics I'd trick my brain with visual cues.
This design looks good. But why is the tweeter reversed in polarity? Doesn't the waveguide set it back to have proper alignment already?
www.audioexcite.com >> Revelation Two – M4 WG
www.audioexcite.com >> Revelation Two – M4 WG
The polarity of one driver needs to be reversed because the crossover slopes are following 2nd order Linkwitz-Riley pattern (and the drivers are aligned via tweeter set-back). With that, you can get an acoustical in-phase response between the drivers but half cycle lag of the lower frequency one. That lag is one thing that a linear-phase crossover want to eliminate.
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