[sdiy] Slightly OT: really loud but light weight speakers

[Joris]

John:

> This looks like a driver only. A horn is required. The horn
> functions as an acoustic transformer. This is how the
> efficiency is obtained.

Harry:

> a horn driver would be less than useless without a horn... and for
> a 500Hz cutoff it will have to be a very large horn (just guessing
> maybe 4" x 10" at the mouth... with no horn it will sound really
> sick (not in a good way)

Thanks for explaining... I was a bit naive to think I could just leave
the horn off. And you're right about the size of the horn, it would be
too large.

> I'd go with several small tweeter horns and live with the 2KHz
> cutoff.

That sounds like a good idea, some more mid and bass would be great
but that's probably just impossible for small light weight speakers.

> My initial idea was to suggest you use two horns, and beat
> two high frequency oscillators... the resulting sum and difference
> tones would be very loud and very obnoxious... make the other
> bots wish they were dead...

Tim:

> Use two or even three horns driven by slightly unstable oscillators
> (about 2 to 2.5 kHz). The beat frequencies combined with the
> noise from the oscillators as they drift about would be really and
> truly nasty.

I like the idea a lot, but I don't want to make the
audience/spectators wish they were dead :)

I'll keep this idea in mind though, the sample player we're using can
do stereo samples...

Right now we've already got some harsh noises in there btw: revving F1
engines, distorted industrial loops, sirens etc. Anyway thanks again
for the help so far, once the new bot is somewhat functional I promise
I'll post some pics and samples!

Joris