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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
dodgealum
hearhere
55 posts
 
One name that should not go unmentioned in this thread is John Dunlavy. He was/is a big proponent of time alignment and his speakers use a first-order crossover. If I recall correctly, John was undecided on how important phase coherence was, but time alignment was crucial. Based on how much I like his speakers, I'm inclined to agree!

Also (and again assuming that I recall correctly), John felt that after his speakers (of course), Thiel came the closest to getting it right.

Apologies to John Dunlavy if I'm misstating any of his positions.
skrivis
30 posts
 
I own a pair of C/3-Ls, and have seen crossover schematics for other models, and they use a simple 1st-order series network. Period. There's no way to get a higher-order electrical network out of what's there.

The published articles I've seen from Bud all talk about 1st-order series crossovers as being superior.

Perhaps he was talking to you about the acoustic response? Or perhaps the "archived" info you're referring to dates back to before modern drivers allowed symmetric 1st-order crossovers?
trelja
3,223 posts
 
As Larry alluded to, Bud Fried did produce time aligned speakers. He sure was a proponent.

Skrivis' C/3L speakers are time aligned, along with the simple first order crossover he stated. They also use true transmission line midbass loading - which is actually MORE important that loading the woofer that way. I'm sure he'll agree that the notes just flat out fly out of the speakers, with no smearing whatsoever. I really like my pair...

Larry, I am certain your speaker venture will be a successful one. Best of luck! Please let me know if I can be of any assistance at all,
Joe
theaudiotweak
2,769 posts
 
Joe about a year ago or so ..well I guess I got into a verbal pissing match with a speaker designer here on the Gon who told me that series crossovers didnt work..Well maybe he couldnt make them work but Fried made them work and the fellows with Starsound made them work..Some designers all to often, only follow what their text book or their professor told them was possible... I have heard Larry's speakers on several occasions always at his home. Always impressive, very musical yet detailed, a great look and way under priced..Tom
trelja
3,223 posts
 
Nice post, Tom!

I think one can argue from a lot of different perspectives, it makes for interesting conversation and enhances everyone's experience here. However, when one tries to say that something that has been to be viable (and over an extended period) "cannot work", one sure puts themselves in a difficult position.

As I reread through this thread, I am more than embarrassed to have noticed that I was flat out backwards in my Zeta description. Zeta of 0.7 is more forward, and 1.2 is more laid back. Can't believe I actually made that mistake in the morning! Surprised no one crucified me on this. Mea culpa, mea culpa...
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