[sdiy] ot: rotating speaker simulation or stupid approach

[Czech Martin]

Why would the doppler effect be lost?

Imagine the following: 100 speakers in a single line, every cm a speaker.
A "sequencer" with interpolation and VCA will make the active of those
speakers move forth and back. What is the difference of that arraw
to a single speaker on a model railway track waggon, moving
foth and back? 

The question is: how many virtual speakers do I need in order to avoid
cancelation effects when doing the interpolation from one
speaker to the next.


m.c.

-----Original Message-----
From: Jaroslaw Ziembicki [mailto:aon.912230836 at aon.at]
Sent: Mittwoch, 2. Juli 2003 17:58
To: Czech Martin
Subject: Re: [sdiy] ot: rotating speaker simulation or stupid approach



----- Original Message -----
From: "Czech Martin" <Martin.Czech at micronas.com>
To: "Sdiy (E-mail)" <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, July 02, 2003 4:34 PM
Subject: [sdiy] ot: rotating speaker simulation or stupid approach


> Has someone heard or read about a circular array of fixed speakers
> in order to simulate a rotating speaker?
> I mean N VCAs and N amplifiers together with N little fullrange speakers,
> with some control that will stear the speakers in a circular fashion.
> I think this would be a hardware implementation of the first idea,
> avoiding any rotating or heavy parts.
> Martin Czech

Many, many years ago I read an article where such method has been
described. It was a kind of a loudspeaker box. I think there were 4 (maybe
6)
loudspeakers, 90 (60) degrees one from another. They used silicon diodes in
the
electronics for gating the signal (a very primitive VCAs). I have no idea
how it
worked. I don't believe it's possible to get the Doppler effect on that way.
You
would get some kind of 3D effect - and it may sound very nice, but not very
close
to the original Leslie...
There was another approach described in this article: the (heavy)
loudspeaker is
mounted inside the box and it doesn't move - and there is a rotating
(lightweight)
"horn" that leads the sound to outside.

Regards
Jarek