🚀 go-pugleaf

In article <1992Nov19.233034.25857@magnus.acs.ohio-state.edu> acampane@magnus.acs.ohio-state.edu (Angelo Campanella) writes:
>
>Look for a book by Harry(?) Olson.
>
>When he was at RCA around WWII, he did a good job at describing the practical
>amenities of loudspeaker design.
>
Yeah, he did a pretty good job. Except he was wrong about how bass reflex
systems work. And he was wrong about how passive radiator systems work,
and we was basically a few bricks short of a chimney describing sealed-box
direct radiators. He was dealing in an era where the understandings of
driver materials, radiation pattern, mutual driver-vent-cabinet
interactions, crossover netaorks and radiation patterns, cabinet
coloration, and so forth were either inheard of or, at best crudely hinted at.

Other than the fact that he got most of it wrong, yeah, he did a good job.

Let's not be to hard, though, on old Harry, he was one of the more
knowledgeable people of the day. But we have learned a hell of a lot since
his time. Yeah, the McLachlan book I recommended is from the same vintage,
but his is a hell of a lot more in terms of theory than Olson's, which is
what the original poster was looking for. And the very basic theory still
stands reasonably well.

>Other than that, keep in mind that all you are trying to do is to drive a
>parcel of air at an audio rate, with a plate (or horn) large enough to produce
>the sound power you want without nonlinear effects due to the compressibility
>of air.  (196 dB = 1 atmosphere).
>
>Most popular way has been a lightweight solenoid driven by reaction in a
>magnetic gap--- the common loudspeaker.
>
>Enclosures are merely to enhance the radiation over the lower range of
>frequencies, the higher being effected by direct radiation fron the driven
>plate ('cone').

This is a tremendous oversimplification of the real problems at hand but,
I presume (or I sincerely hope) they are, in fact, stated as such
intentionally.

By the way, I wouldn't sweat trying to reach 196 dB. That's the sound
pressure level of a Saturn V launch AT THE PAD. (Saturn V's were spec'ed
at producing about 6 million whats of acoustic power at sea level,
equivalent to about 189 dB SPL at close range. Might make for an
interesting surround-sound demo, though!)



-- 
|                Dick Pierce                |
|    Loudspeaker and Software Consulting    |
| 17 Sartelle Street   Pepperell, MA  01463 |
|       (508) 433-9183 (Voice and FAX)      |