Leslie Update

[Doug Tymofichuk]

Greetings, all!

Over the weekend I found some time to play with my slip 
rings. Just as a test, I attached the center of a 14 inch 
long bar of aluminum to the slip ring assembly. On one end 
I mounted an old tweeter and on the other a small full 
range speaker. I wired them together and through the slip 
rings, and then hooked it up to the stereo.

Spinning the assembly by hand, I could get it up to about 
100 rpm, which sounded pretty good. The high frequencies 
from the tweeter alternating with the full range speaker 
was a neat effect, which could be modified with filters on 
the input signal. I found a big difference with putting my 
ear very close to the speakers as opposed to farther away, 
so I think two or more microphones at different distances 
is an excellent idea. There was very little mechanical 
noise from the slip rings at this speed, without even 
attempting to acoustically shield them, at higher speeds 
it may become a problem (have to drive it with a motor to 
find out)... This was with much less than 1 watt of 
amplifier drive power, as that was all that the full range 
driver was rated for. The effect was quite pronounced, even 
my wife was impressed, a significant feat in itself! Even 
if it did not sound any better than this when completed, I 
would be quite happy with it I think.

Based on this, I am going to continue further with 
experimentation, adding a variable speed motor drive, 
positioning the drivers nearer to the center of rotation 
and adding baffles or horns to bring the sound back to the 
edge of rotation (for faster speed changes; less momentum), 
adding microphones, and placing the whole works into a box 
for wall reflections, resonance, and isolation.

I'll keep you posted. 

----------------------
Doug (head still spinning) Tymofichuk 
dougt at cancerboard.ab.ca