[sdiy] About that spherical impulse generator...

[Harry Bissell Jr]

The small moving mass could provide excellent
damping... and if you had just the right amplifier
driving it I bet you could get very good pulse shapes.

OK good idea.

H^) harry



--- Glen <mclilith at charter.net> wrote:
> There was someone recently talking about building a
> roughly spherical
> shaped speaker array, for the purpose of capturing
> the impulse response of
> an acoustic space. I assume that swept sine waves
> were going to be played
> on the 24 speakers of this array.
> 
> What about using a dirac pulse instead? Since the
> speakers can't follow the
> transient of the dirac very well, replace them with
> a spherical array of
> piezoelectric discs. These are cheaper than
> speakers, have a much better
> transient response, and for the short duration of
> the dirac pulse, could be
> driven much harder than they normally would be for a
> continuous signal. I
> believe that someone said that the speaker beaming
> issue was worse for
> larger diameter speakers and higher frequencies.
> Since these piezo elements
> are much smaller than most speakers, you can pack
> many more of them on the
> surface of your approximated sphere, for any given
> sphere diameter. I would
> think this should reduce the beaming problem a great
> deal. I know, you
> probably don't think that piezo discs could generate
> enough volume, but
> keep in mind that there will be MANY of these discs
> pulsed to their
> absolute maximum peak volume, all at the same time.
> It only has to be loud
> for an instant. I think it just might work, at least
> for smaller spaces,
> perhaps not even as small as one would first think.
> 
> Does anyone think it's a crazy idea? ...an
> interesting idea? ...maybe even
> a good idea?  :)
> 
> 
> later,
> Glen Berry