This is one of tomservo's posts on audioasylum
Posted by tomservo ( M ) on December 29, 2004 at 12:56:06
In Reply to: Pinging Tom Danley posted by KCHANG on December 28, 2004 at 14:29:24:
Hi Kurt
Hey I remember the day you guys came up and aren’t you the fellow who had those amazing little full range drivers at the Chicago horn show some years ago too?
I was really impressed with those (Fostex I think you said?) drivers on your "casual baffle board".
As I recall, the speakers I had at the time you guys came up were a square, 60X60 2 way Unity horn and a pair of 10 inch woofers out board on the sides. That became a product called a C-3 and a couple years after its introduction the configuration (with side firing woofers to produce forward lf directivity etc) was not so loosely copied by a larger pro-sound company as a "line source" concert speaker.
That product (the prototypes you heard) had pretty good phase response through the horn range (4, 5 inch mids, 1 B&C compression driver), being about + - 120 degrees of acoustic phase from about 350Hz to 10KHz using TDS. Below this they were like a regular direct radiator in a vented box (a bunch more phase associated with direct radiation and the box low cutoff).
Normal, multiway speakers would typically have hundreds or thousands of degrees of phase span in the same range, measured the same way fwiw.
The "best" so far (using only passive filters) that is in production is the Runt, which has an acoustic phase which is at about +45 degrees at 100Hz, falling to about zero at 300Hz, staying around zero to about 3KHz and then rising to about +450 degrees at 20KHz (reflecting an equivalent shift in position reaching about ¾ inch at 20KHz.).
That last rise can be fixed but I could not hear the difference and more parts cost more $.
I intended to snag a pair of these to let Tom try them, seeing as how he has left the world of (large) horns behind, maybe its the effect all that iron he was around I dunno
The most recent effort is the td-2, this is a 3 way horn (an attempted improvement on the td1 using what I learned since it was designed) and I have had several versions of that which were "near zero" even more of the range.
This remains at the limited prototype stage.
The company Yorkville in Canada is making several versions of the Unity under license and are doing well with the product. Not only that but I made the acquaintance of a couple nice people up there who love speakers as much as I do, in Bill’s case, maybe more.
Anyway, I like the company’s approach and double that for the folks I have met and deal with.
Servodrive / SPL went the route of side by side demo’s and some trade articles which leads to sales, but that alone is not what is needed to grow beyond those that can be reached that way. This resulted in a number of high visibility installation’s but again usually only when a side by side demo was possible.
As a result the REP’s who show the product have good sales, the ones who’s "trunks are full" already or "have a bad back" (don’t demo product) don’t sell much.
In frustration with this approach and other issues, I quit on Oct 15th and am pursuing a couple other possibilities with several new speaker inventions.
Servodrive / SPL seems to be putting all their eggs in the military / industrial sound basket instead, oh well, I just don’t find the idea of producing the sound and intensity of a jet engine (for active sound cancellation and testing) to be as interesting as music / sound reproduction for "listening".. If you horn guys have another local meeting and want to hear a pair of the prototype td2’s (although the horns are not painted), I do have a pair.
Cheers,
Tom Danley
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Topic: Tom Danley leaves Servodrive/Sound Physics Labs??? (Read 17448 times)