Time coherence - how important and what speakers?

Some consider time and phase coherent extremely important especially Richard Vandersteen.

But then you hear people rant and rave about the Hyperions, the Dynaudio Evidence Master and Temptation, the Krell LAT-1 all of which are not (I believe). From what I've read and heard from others, I would probably lean toward a speaker that was time and phase coherent in design.

Don't know about the Joseph's but the Meadowlark Blue Herrons selling for $9k are also time and phase coherent. Much effort appears to have been put into the the BH's, much like the Vandersteen Model 5's.

But on paper (I've not listened to either), the Vandersteen's appear to be over the top when it comes to design and detail. And they're only $1k more than the Blue Herons.

-IMO

While I have heard speakers that I enjoyed that weren't Time coherent I am consistently attracted to speakers that are. To my ears it is important. Dunlavy, Meadowlark, Quad, Spica, Thiel and Vandersteen are. I'm not sure but I think that the ESL Acustats, Audiostatic, German Physics, Huff omnis, Original Walsh, Yankee, Museatex Mel, ESL Sound Labs, Stax, Martin Logan CLS & CLZ might be ? Does anybody know about these last possibilities?

Any single-driver speaker, whether cone, walsh, electrostatic, or whatever, is automatically time and phase aligned. That's one of their biggest advantages.

I may be wrong but I don't believe that Karl's statement is correct. Highs come at you quicker where lows are much slower. A flat diaphragm is not timed aligned by looking at its impulse response and other factors. The frequencies are reproduced at the same time but do not arrive at your ears at the same time. I am aware of only a handful of time aligned (and/or phase correct) speakers. Going back through a lot of specs, etc., nobody has ever called an electrostatic time aligned that I can find. They are certainly not phased aligned. Look at the electrostatic impulse response and phase graph. The phase angle is all over the place.

Two points for you Bigtee.

Number 1 - If the highs travel much faster than the lows, then how does aligning the acoustic centers of the drivers time-align them? Answer: The time alignment attempts to simulate a single source of the sound so that the sound emanates from the same plane. The tweeters are not moved back to compensate for the speed of the frequencies. They are moved back to align the acoustic centers of the drivers for line-source radiation from the same plane.

Number 2 - All drivers have phase charts that are "all over the place". Phase alignment does not mean that there is not phase change. Phase alignment can mean 2 things. It can mean that the multiple drivers are crossed-over in such a way that the phase changes induced by the crossover are within a certain tolerance between each driver. It can also refer to the phase relationship between the driver and the port in a reflex design, or the positioning of the speaker relative to the behind wall, in a dipole radiator speaker. Many drivers will even reverse phase, at or below the resonant frequency of the driver. Every driver that I am aware of has phase irregularities. It is inherent in the electromagnetic transducer design.

From what I have heard, generally "time-aligned" means the acoustic centers of the drivers are aligned. And "phase-aligned" means that the crossovers use a relatively phase coherent 2nd or 4th order alignment.