At 11:07 03/03/97 +0800, you wrote:
>General morphing technique in 3 easy steps:
>
[snip]

>Obvioulsy, this is abstract, and doesn't say how to find a space for
>the two sounds to live in, but it is, in fact, what every morph
>construction does. The two infinities here show how vague we are being
>when we talk as if there were one "right" morph, or as if there could
>be a definitive piece of morphing software.

Indeed. And of course there is no one final and true absolute and
definitive 'best' morph for any two sounds. 

The important criteria though are not the technical ones. The model space
doesn't matter. What does matter is that the morph *sounds* convincing.
Whether you do this by technical finesse or psychoacoustic sleight of hand
is irrelevant - although obviously the broader and more effective the range
of models you have to work with, the more likely it is you'll get a
succesful result.

>We find two different models that have parameter regions where they
>produce sounds that are perceptually similar. Then to "morph" from a
>sound made with one of the models to a sound made with the other, we
>chose a parameter path that bring sound A into the overlapping
>perceptual region, switch models as subtly as possible, and continue
>on the path in the other model's parameter space until we arrive at
>sound B.
>
>In this way, both sounds don't actually reside in the same parameter
>space, but a convincing "morph" can still be achieved.

Yeah - that will work too. (But I wouldn't want to try it in practice
unless I really had to. :) )

As a more general principle, the morph becomes more difficult the more
information you have to deal with. Morphing between a square wave and a
triangle wave is trivial. Morphing smoothly between a Bach violin partita
and a Mozart piano concerto requires a total control over musical and sonic
considerations which is going to be unreachable in practice. (At least by
anyone with an IQ that doesn't run into four figures and *really* fast
hardware.)

It's the range of potential morphs in between these extremes that are
achievable now - often involving vocal sounds, because they seem unusually
compelling to most people - that I think are most interesting from a
compositional point of view.

R.