[sdiy] Update on my arpeggiator

[Ian Fritz]

At 04:06 PM 6/3/05, phillip m gallo wrote:

>Inquisitive, not argumentative, what would a spiral sound like?

This is an interesting topic.  There are several parameters that define or 
characterize a spiral waveform.  These are perhaps easiest to think about 
using the 'scope trace, or geometric, picture of the wave.  Here's my list 
of characteristics:

1.) Minimum radius.  The spiral does not have to start from the origin.  It 
can start part way out.  So the radius of the wave might go from 2 V to 5 
V, for example.

2.) Number of loops in the spiral.  If there are lots of loops then the 
sound has definite and separate-sounding low- and high-frequency components.

3.)  Reset path.  The reset (or jump from the inside to the outside of the 
spiral, or vice versa) may be  nearly instantaneous, as in the Saw 
multiplier example, or it may take a much longer time.  My nonlinear 
circuit box can even produce a relaxation-like oscillation which consists 
of a slow ramp followed by a rapid spiral that resets the ramp to zero.

As you might imagine, there is quite a range of sounds obtained by varying 
these parameters.

   Ian