That would be tough considering the X-2s are manually time aligned when set up by the dealer. Unless of course the set up procedure was not followed to the letter.
phase/time alignment
- Thread starter rblnr
- Start date
According to all the measurements I've ever seen, none of the Wilsons are time-aligned designs.
That's why I asked the question about the comparison.
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A musical waveform is a complex overlay of frequencies, amplitudes, and phase relationships. With current technology, no single transducer can reproduce the full range of music at realistic sound pressure levels and maintain consistent dispersion. The only practical solution to this problem is a multiple driver array, but multiple drivers introduce their own set of problems, chief among them the challenge of preserving the precise time relationships of the musical waveform. The fact is, misalignment of the drivers by small fractions of an inch will audibly degrade transient performance, soundstage height, width, and depth, as well as introduce tonal anomalies that destroy the otherwise convincing "presence" of an instrument or a singer's voice.
The key to solving this problem lies in the vertical alignment of the various drivers in an adjustable modular array so that each driver's waveform propagation "matches up" with its neighbors' in such a way as to create the sonic equivalent of a single point source.
Wilson's patented Adjustable Propagation Delay has long set the standard for precise driver positioning in order to ensure correct propagation alignment for a wide range of listening locations. Alexandria took this technology a step further with the introduction of Aspherical Propagation Delay. Not only can each driver module move forward and back in the time domain, but each module rotates on its polar axis to achieve optimal dispersion for any chosen listening postion.
In conventional systems, drivers are mounted in a flat baffle such that each driver is positioned at a different distance in relation to the listener. Thus, energy from the tweeter arrives at the listening position in advance of the midrange, which in turn arrives before bass generated by the woofer. The problem of achieving both time-domain coherence and optimal driver dispersion is only exacerbated by larger speaker systems. Most speaker designers simply ignore this measurement.
With Aspherical Propagation Delay. Alexandria's driver modules adjust to achieve optimal driver dispersion for nearly any size room and for any chosen listening position. The Alexandria and now the MAXX Series 3 are the only loudspeakers to utilize these combined innovations.
Introduction • Epiphany in Vienna • The Drivers • The Crossover • Aspherical Propagation Delay • Specifications
Company Conversations with Dave Wilson
Authentic Excellence
Authentic Values
History
Events
News Current Newsletter
Newsletter Archives
Press
Reviews
Awards
Dealers U.S.
International
Contact
Pro Users Music Industry
Motion Pictures
Home
A musical waveform is a complex overlay of frequencies, amplitudes, and phase relationships. With current technology, no single transducer can reproduce the full range of music at realistic sound pressure levels and maintain consistent dispersion. The only practical solution to this problem is a multiple driver array, but multiple drivers introduce their own set of problems, chief among them the challenge of preserving the precise time relationships of the musical waveform. The fact is, misalignment of the drivers by small fractions of an inch will audibly degrade transient performance, soundstage height, width, and depth, as well as introduce tonal anomalies that destroy the otherwise convincing "presence" of an instrument or a singer's voice.
The key to solving this problem lies in the vertical alignment of the various drivers in an adjustable modular array so that each driver's waveform propagation "matches up" with its neighbors' in such a way as to create the sonic equivalent of a single point source.
Wilson's patented Adjustable Propagation Delay has long set the standard for precise driver positioning in order to ensure correct propagation alignment for a wide range of listening locations. Alexandria took this technology a step further with the introduction of Aspherical Propagation Delay. Not only can each driver module move forward and back in the time domain, but each module rotates on its polar axis to achieve optimal dispersion for any chosen listening postion.
In conventional systems, drivers are mounted in a flat baffle such that each driver is positioned at a different distance in relation to the listener. Thus, energy from the tweeter arrives at the listening position in advance of the midrange, which in turn arrives before bass generated by the woofer. The problem of achieving both time-domain coherence and optimal driver dispersion is only exacerbated by larger speaker systems. Most speaker designers simply ignore this measurement.
With Aspherical Propagation Delay. Alexandria's driver modules adjust to achieve optimal driver dispersion for nearly any size room and for any chosen listening position. The Alexandria and now the MAXX Series 3 are the only loudspeakers to utilize these combined innovations.
Introduction • Epiphany in Vienna • The Drivers • The Crossover • Aspherical Propagation Delay • Specifications
This is time aligned:
http://www.stereophile.com/floorloudspeakers/vandersteen_model_seven_loudspeaker/index5.html
So is this:
http://www.stereophile.com/floorloudspeakers/1208thi/index4.html
This is not:
http://www.stereophile.com/audaciou...ialties_maxx_series_3_loudspeaker/index6.html
One reason folks need to learn to read measurements.
The JL subwoofers have a "phase" adjustment that allows the user to effectively delay their signal in order to synch with the main loudspeakers. This adjustment can be made fairly well with just an SPL meter and a test tone close to the crossover frequency.
Lee
Lee
The results of the writer are consistent with what a lot of other research shows as well. Most companies choose not to chase time alignment. Vandersteen and Thiel are two companies that produce time-aligned designs, however, and have also addressed some of the compromies inherent in such designs. Vandersteeen's new drivers are examples: Break-up modes are well outside the operating band.
Thanks Jeff,
Now I wonder if JA just plunked the Maxx on his driveway and measured them without the top modules being focused.
It could happen right?
Note: I'm not a Wilson owner. Others do time alignment electrically or mechanically without adjustability. As for adjustability it appears, the principle is the same as Ascendo where alignment is done for specific distances not just from driver to driver but listening position as well.
The question in my mind then is given the velocity of sound being constant given certain variables like air pressure, how is the distance to listening position an important factor? Could the factory setting be right when it comes to drivers relative to each other but when adjusted, wrong for that but right for the listening position?
Now I wonder if JA just plunked the Maxx on his driveway and measured them without the top modules being focused.
It could happen right?
Note: I'm not a Wilson owner. Others do time alignment electrically or mechanically without adjustability. As for adjustability it appears, the principle is the same as Ascendo where alignment is done for specific distances not just from driver to driver but listening position as well.
The question in my mind then is given the velocity of sound being constant given certain variables like air pressure, how is the distance to listening position an important factor? Could the factory setting be right when it comes to drivers relative to each other but when adjusted, wrong for that but right for the listening position?
It's not coincidence that several companies that use first order slopes design their own drivers too. The shallower rolloff taxes the driver more than, say the 24db rollofff of 4th order slopes. My old Epos ES14s -- a speaker that had some real magic, used a house designed midwoof and tweet -- it would have been difficult to accomplish the very minimal xover (straight into the midwoof, single cap to the tweeter) with off the shelf parts. Thiel, Vandersteen, Reference 3A, etc. all use proprietary designs on some or all drivers.
In many Stereophile speaker measurement sections it's noted where drivers are wired in inverted polarity vs. others in the same box -- this presumably to smooth frequency response and perhaps compensate for the phase shift inherent in steeper slopes. I'm not dogmatic about this, but looking back over the speakers I've really liked, nearly all been first order, phase coherent designs.
The Ascendo M-Fs allow for similar fine adjustment to accommodate a given listening distance.
In many Stereophile speaker measurement sections it's noted where drivers are wired in inverted polarity vs. others in the same box -- this presumably to smooth frequency response and perhaps compensate for the phase shift inherent in steeper slopes. I'm not dogmatic about this, but looking back over the speakers I've really liked, nearly all been first order, phase coherent designs.
The Ascendo M-Fs allow for similar fine adjustment to accommodate a given listening distance.
A while back somebody got a hold of a pair of speakers on the west coast which was used in a favorable review. The new owner never got them to sound right and gave up. In frustration he sold them on-line and shipped them to Japan. The owner in Japan also was disappointed and took them into a shop to see what was wrong. The shop discovered that the drivers had been wired out of phase, reversed/corrected the connections and all was good after that (from what I know).
Now I wonder about what I thought I knew after reading rblnr's quote.
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I have to wonder if a coaxial speaker has an inherent advantage when it comes to timing.
Example-1:
First Generation KEF Uni-Q Driver
http://6streetbridge.blogspot.com/2008/11/first-generation-kef-uni-q-driver.html
Example-2:
Great Plains Audio
http://www.greatplainsaudio.com/2_way.html
And if coaxial drivers are so great timing wise, why are the found typically in automobiles and in-wall H.T. systems and not in ultra high-end loudspeaker systems?
Example-1:
First Generation KEF Uni-Q Driver
http://6streetbridge.blogspot.com/2008/11/first-generation-kef-uni-q-driver.html
Example-2:
Great Plains Audio
http://www.greatplainsaudio.com/2_way.html
And if coaxial drivers are so great timing wise, why are the found typically in automobiles and in-wall H.T. systems and not in ultra high-end loudspeaker systems?
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Thiel, ATC, Cabasse, BG and some others in addition to KEF go the coaxial route. And the argument is that it's more of a point source, and better time wise as the voice coils are aligned. The cone around the high frequency driver can act as a waveguide.
A reason it's not so common is that it usually means building your own drivers which most manufacturers don't do.
some info from Thiel:
http://www.thielaudio.com/THIEL_Site05/Pages/FAQs/faqtimephase.html
A reason it's not so common is that it usually means building your own drivers which most manufacturers don't do.
some info from Thiel:
http://www.thielaudio.com/THIEL_Site05/Pages/FAQs/faqtimephase.html
I'm coming in late so forgive if out of place...
While I think Bob nailed the main reason (cost), another reason coaxial/triaxial speakers are uncommon is the refractions and interaction among drivers at the output side are harder to control. For example, the upper frequencies from the woofer hit the horn flare of the midrange/tweeter and hurt the sound a bit. Sonic design gets tricky... The design and implementation is also much more complex from a mechanical design point of view.
While I think Bob nailed the main reason (cost), another reason coaxial/triaxial speakers are uncommon is the refractions and interaction among drivers at the output side are harder to control. For example, the upper frequencies from the woofer hit the horn flare of the midrange/tweeter and hurt the sound a bit. Sonic design gets tricky... The design and implementation is also much more complex from a mechanical design point of view.
A while back somebody got a hold of a pair of speakers on the west coast which was used in a favorable review. The new owner never got them to sound right and gave up. In frustration he sold them on-line and shipped them to Japan. The owner in Japan also was disappointed and took them into a shop to see what was wrong. The shop discovered that the drivers had been wired out of phase, reversed/corrected the connections and all was good after that (from what I know).
Now I wonder about what I thought I knew after reading rblnr's quote.
Some reading about crossovers, and there is a bit about wiring out of phase toward the bottom:
http://www.aperionaudio.com/AperionU/crossover.aspx
You added 4-makes to my short list of one (KEF), thank you.
EDIT: found a few of the others not yet named......some are more like "Dual Concentric" not Coaxial though.
http://www.soundimage.dk/Different-col/Coax.htm
http://www.soundstagenetwork.com/avtour2009/he_dly06.html
http://www.dagogo.com/view-article.asp?harticle=211
http://www.madisound.com/manufacturers/seas/prestige/passive-coaxial.php
http://www.transmissionaudio.com/
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Keep in mind that timing inaccuracies happen in the midrange and upper midrange where wavelength is much shorter. 3000 Hz, has a physical length of (1128 / 3000) = .37 ft or 4.4 inches. So 2.2 in. is reverse polarity (180 degrees). If crossover frequency happens to be near 3kHz, reverse polarity IS a big deal. Even a 1 in. difference equals to a 90 degree phase shift. Physical alignement is only one part of the problem - or solution, because each crossover component compounds the problem a little more.
Physical alignement has limited effect because it can be exactly right at only one point in space, and wrong most of the time, so other conditions must be carefully evaluated by the designer. I find that some restricted output on axis and at crossover frequency (ex. 2,5 kHz) might be beneficial and tends to give a slightly more spacious sound.
Physical alignement has limited effect because it can be exactly right at only one point in space, and wrong most of the time, so other conditions must be carefully evaluated by the designer. I find that some restricted output on axis and at crossover frequency (ex. 2,5 kHz) might be beneficial and tends to give a slightly more spacious sound.
What the Wilson fails to note is that careful offsetting of the mid and (or) tweeter in the vertical plane can achieve the same result - time alignment - in a much simpler way. Moreover, optimal timing can be dialed in with proper toe-in. It is true, however that most manufacturers ignore this.
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