[sdiy] Timbral musings

[Ian Fritz]

Hi folks --

I've been thinking some about a dilemma I've noticed with regard to 
waveshapers. Let's try out some ideas here.

The dilemma is this:  On the one hand, if you listen to a waveshaper as it 
is tuned (or modulated) through a range of timbres, the tuning often seems 
to have a "weak" effect. Similarily if you take a multistep waveshaper and 
shove the sliders around you get the impression that all the sounds are 
more or less similar.

On the other hand, if you put the waveshaper in a patch and try to get a 
certain sound you may have in mind, you notice that small differences in 
waveshape make a significant change in the sound. In fact it can take very 
careful adjustment to get the sound you are after.

So how do we reconcile these effects?  I think the answer has to do with 
the physics and psychoacoustic of how we hear and analyze sound.

When you consider listening to a sound in a room, you might naively expect 
to get very confused because of all the reflections, phase cancellations, 
etc.  The reason you don't, as I have read, is that the ear/brain actually 
averages spectra over different positions of your head as you move around 
slightly.

Thus it ends up taking quite a bit of time to analyze a sound you are 
hearing. I think I notice this effect when my alarm radio comes on in the 
morning. Even if I am awake, I cannot immediately tell what instruments are 
playing -- it takes a couple of seconds to lock onto the sound.

 From these ideas, I think that when you sweep a waveshaper your 
head/ear/brain simply can't work fast enough to keep up with the 
changes.  There are big differences in sound, but they just don't register. 
That is why my demo clips for the "Wavolver" waveshaper emphasize 
steady-state tones (with quick sweeps in between).  I was just listening to 
those again, and it really does seem like it takes several seconds to 
adjust to the changes.

The counter-argument here is that filter sweeps give a "strong" 
effect.  Perhaps this is because the filter is so drastic in subtracting 
high frequencies, whereas a raw shaper waveform always has lots of harmonics.

I would really be interested in hearing what you good people think about 
these ideas.

Regards,

   Ian

   (Wavolver clips are here: http://home.earthlink.net/~ijfritz/sy_cir6.htm  )