Phase Coherence or Time Alignment: Which More Imp?


This thread is really a follow on from a prior one that I let lapse. Thanks to everyone who contributed and helped me to better understand the importance of crossover design in building a loudspeaker. What I gathered from the last thread that there are opposing camps with different philosophies in crossover design. Leaving aside for a moment those that champion steep slope designs, my question is for those who have experience with speakers that are time aligned and/or phase coherent (using 1st order 6db per octave crossovers). Which is more important, phase coherence or time alignment? In other words, which more strongly influences the sound and performance of a loudspeaker? The reason I ask is because of the four speaker lines currently on my shortlist of floorstanders, three are either phase coherent or time aligned or both. The Wilson Benesch Curve's/ACT's and the Fried Studio 7 use 1st order crossovers but do not time align the drivers through the use of a slanted baffle. The Vandersteen 5's and the Quatro's both time align the drivers and use 1st order crossovers. I guess what I am asking is do you need to do both or is the real benefit in the crossover design? I'd appreciate your views.
BTW the other speaker is the Proac D25 and D38
128x128dodgealum
Roy, I played sax for over 30 years and I became sold on time and phase speakers when listening to this instrument as well as other woodwinds (and other various instruments.) Other speakers with high slopes just destroyed a lot of what should have been there. For some years (in the past), I blamed it on electronics and/or the recordings. With time, I discovered what you already knew. I have found very few speakers that get the attack, decay and harmonics correct for me. It was extremely interesting to read your explanation and examples. It definitely follows what I personally hear.
I have noticed the positive recommendations you are receiving here and other places on your speakers. With the apparent unfortunate situation with Meadowlark, it looks like you, Richard V. and Thiel must carry the load.
It is good to see Green Mountain Audio being successful. I'm certainly going to have to give your product a whirl at some point.
Curently, I am investigating no negative feedback equipment. With time and phase coherent speakers, it has proven to be extremely interesting. There is something to it for sure. It seems to open up the presentation even more and further enhance that "You are there sensation." It is also interesting that time and phase coherent speakers, for all the critcisms they get for being laid back and not transparent, sure show this difference.
Thanks Roy,
indeed these difficulties can be minimized with careful design!
Thats why I use Tannoy LittleReds. It uses a combination of
first and second order filters. The phase response curve shows it to shift the entire audio spectrum uniformly by 30deg compared to amp output with a slight dip and a bump around the crossover frequency (+8deg,-10deg). So it acts as a time delay
(unavoidable) with a maximum phase shift of 18deg but this is limited to about 200hz either side of the x-over frequency ie the shift starts at 1k,
goes through zero (that is the 30deg total shift) at 1.2k rises again and is back at zero (30deg) at 1.4k.
Also, being point sources, they stay in phase no matter where you are in the room, unlike common multi-driver systems.

Personally, I have NEVER heard a speaker to be 'too analytical' or 'too revealing' although I heard speakers being 'too forward' or 'fatiguing' these usually featured metal-dome tweeters. I would have thought that 'analytical' and 'revealing' are essential attributes of any accurate speaker.
Without being 'analytical','revealing' and accurate any critical listening is
obviously impossible. People having problems with these attributes should probably by a Bose waveradio and just be happy with all the money they saved. They are the reason that high quality audio is in the dire state its in.
(Sorry, didn't mean to be ranting but statements like 'too analytical' just get me going. I am also aware that it wasn't you who said it, so don't take it personal.)
In my own experience, based on spending time in recording studios and listening to every speaker I can since I was 15 I have to say that Tannoys are closest to the real thing followed by decent studio monitors. Than come a variety of planars ( fantastic at low volume but lacking in macro dynamics),
full-range drivers ( great dynamics and imaging, bad at low volume, dodgy treble and (if in a horn) lumpy bass response.
After that the majority of dynamic speakers who do everything somewhere between average and badly.

This, of course, is a grotesque over-generalization as there are really bad studio monitors and really good HiFi speakers. I have not come across any
green mountain gear here in Europe so I cannot say anything to your product.
Overall you still have to look at the whole speaker-system and not just the xover, my Tannoys have loworder filters and sound fantastic, most studio monitors use fourth order and sound very good and back in the 80' I came across some 5way, first order filtered Dynaudios which also were excellent!

Cheers Golix
(haven't founded anything but...
can explain gravity without
bending space)
Though my own sensibilities lie with Roy, and the very cogent points he put forth, I want to make it clear that as Jeff Joseph basically said, there's more than one way to skin a cat. Jeff's speakers have established themselves as fine a loudspeaker as one can find in this hobby. I admire and respect both he and his products.
Jeff Joseph seems like a very good guy, he gave a nice presentation in New York last week. Yes, with his speakers' performance he finds himself in good company, but only through a time coherent speaker can one accomplish the acoustic output as a duplicate of its electrical input. The infinite slope cannot maintain the acoustic waveform.

Richard Vandersteen though that I'm more sensitive to time domain shifts than most people. Not that I have golden ears, but it's just where my sensitivies lie. For other listeners, higher order cross-overs may be perfect for them - so yes, there is more than one way to skin a cat.
I have no doubt Jeff Joseph is a good designer based on his beliefs and having never met the man, I'll take your word that he is a good fellow(which I'm sure he is.) However, I'm of the camp that there is only one way to skin a cat. These two designs are too far apart for even a sorta right pick between them. Sorry, this falls into a more right or wrong area. Otherwise, it forms a who cares theory (which is probably a good one since most will pick what sounds best to them no matter what the design.)
My opinion certainly doesn't invalidate anyone else's choice. I'm sure these speakers have a loyal following just as most other brands. They just weren't for me.