David Gravereaux <davygrvy@[EMAIL PROTECTED]
> wrote:
>
>Its been proven by numerous users that the piezo array does work.
>Myself, I'll stay with my EV DH3 on HPT94 constant directivity horns and
>when I build my DR280s. I'll use them not the piezo array. Yes, it's
>old-world 1940s tech and scary. Yes, Bill is rather counter culture.
My first experience with the piezo array was at Georgia Tech in the
mid-eighties, where the EE department auditorium had a pair of speakers
that someone had built as an undergraduate project. They employed an
arc of Motorola piezo tweeters with some phase ****ft networks, and they
did
indeed provide good directionality in one plane while providing a nice
wide and even pattern in the other. The comb filtering was not very
audible once you got about fifteen feet away.
The problem with them is that they sounded shrill and shrieky, and I have
since found that this appears to be a characteristic shared by all of the
piezo drivers out there. Some are better than others; I think Vandersteen
did a remarkable job with the things. But they all sound shrieky.
Not that horns don't have some severe problems too.
>James should consider the Omni10 for tops and maybe the Tuba24 for the
>subs if he needs the bottom.
If I were an amateur looking to build some homebrew speakers for a band,
I'd look at coaxial drivers. Selenium and Radian make some good sounding
ones for cheap... PAS, Tannoy, and BMS make some even better ones for more
money. The advantage of the coaxial is there is very little engineering
work to do... you put the driver into a box (and you can use the
manufacturer's
numbers or plug-and chug the box alignment formulae to figure the volume
out yourself), use the crossover the manufacturer supplies or copy the
design
they recommend, and go. The top end horn is integrated into the low end
driver, so you don't have to fight to get them to sound right together
because
the manufacturer has already done the hard work for you.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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