Time Phase/Coherence-Vandy 5A vs. SL M-1

So let me ask you - will your purchase decision be based on which loudspeaker sounded best to YOUR ears, or will it be based on someone else's answers to technical/philosophical questions about those speakers?

Rex,

Of course I will purchase what I perceive to be the best sounding loudspeaker. I just find it fascinating that there are so many design approaches to excellent sounding speakers. Sometimes opened ended questions/comments generate interesting and spirited discussion on the board.

Besides world class performance in many different areas, two aspects that I find particularly appealing with both the Vandersteen 5A and Sound Lab M-1 speakers is how utterly non-fatiguing these speakers are during prolonged listening.

There are some very interesting and informative threads in the archives. Type in "phase coherent" and "time coherent" in the search archive. I'm a believer in time and phase coherent speakers,assuming all other parameters are properly dealt with. Still, what ultimately matters is what speakers sound best in your system and in your particular listening room.

Disclaimer - I peddle Sound Labs.

Okay I'm wading into deep waters here, not being an engineer. But maybe that's okay - I'm a dealer after all, fin on my back, perpetual toothy grin, hmmmm... maybe these deep waters will provide an opportunity or two. A tasty exchange of ideas, if you will. Food for thought, perhaps. Cue the theme from "Jaws"...

I think I found the quote Fgm4272 was referring to. In an interview published in Soundstage online magazine (http://www.soundstage.com/interviews/int07part2.htm), Richard Vandersteen said:

"Panels tend to be large and the distances from the panel to the listener’s ear are different for each point you measure. A sound radiating from a panel has many points of origin on the panel and those all have different distances to travel to get to the listener’s ear. So panels introduce quite a bit of time smear for the most part."

Richard Vandersteen's assertion would be true if panels did not radiate as coherent line sources or planar sources (which they do, as can be demonstrated with fairly simple measurements).

If Richard's position was correct - that is, if we heard the sound from each point on a planar diaphragm at a different instant (requiring that the diaphragm not behave as a line or planar source) - then the output from such a panel would be so smeared that intelligibility would be significantly degraded (see Helmut Haas's landmark paper entitled "The influence of a single echo on the audibility of speech", JAES March 1972; and James M. Kates' "A perceptual criterion for loudspeaker evaluation", JAES December 1984). This smearing would be easily revealed by an oscilloscope trace of the speaker attempting to reproduce a square wave. I recall a very detailed brochure publised by DCM years ago demonstrating how close their speakers came to reproducing a square wave - bettered only by the (drum roll please....) flat panel Quad ESL!! (Now commonly known as the "57".)

Roy Johnson of Green Mountain Audio, another designer of well-respected time and phase coherent loudspeakers, recently wrote:

"Full-range single panel speakers are/can be minimum phase - and IMO why they are enjoyable, even at the expense of sitting dead on center because of that large panel vs. the short treble wavelengths."

Here's the link (scroll about 3/4 of the way down the first page to the last paragraph of Roy's post): http://www.audiocircle.com/circles/viewtopic.php?t=9652&postdays=0&postorder=asc&start=0

[Note that the faceted-curved panel of the Sound Labs avoids the small sweet spot problem Roy mentions.]

Now despite all the foregoing devastatingly convincing arguments (saying that tongue in cheek, folks), I think what really matters most is what Fgm4272's ears tell him. And if it's a tie, then I'll readily concede that the Vandies kill the SLabs in the WAF department.

Cheers,

Duke