Re: Necker Cube Illusion

Hi Paul,

Yes, agreed. The bassoon formants must vary a lot between registers, and the piano
partials stretch by varying amounts depending on register / heaviness of the strings. For
those two instruments, best solution may be to play them very high.

For the illusion to have the best chance of succeeding, one will need an instrument that
sounds distinctive at a high pitch (so that it can be recognised using releatively few
partials) and sounds fairly similar over a wide range of pitches.

If one goes back to your original idea which Joseph Pehrson was keen on doing (which I
prob. had in mind), then ones looking for a harmonic, and an inharmonic instrument with
those properties. Just to take an example out of many poss. in standard Midi patch set,
to give the idea, say, oboe and glockenspiel.

As for decaying partials, and partials fluctuating in pitch as the note proceeds - one
could do that in MIDI too if one had the data for it, using pitch bends and the expression
controller.

Even new partials entering in as the note proceeds might be possible, by starting them at
the minimum expression controller value that one can switch notes on at with ones
soundcard / synth, so one hopefully won't hear much attack. Then increase to the desired
expression level for them.

One will already be playing each partial in a new channel for the pitch bends, so adding
fluctuating pitches and expression is certainly possible.

In fact, I'll add it to the "For the future" list for FTS. Actually, it already has about
as much on it as the FTS 1.09 beta has since the 1.082 release, so may be talking about a
couple of releases from now for some of the options (or possibly a series of smaller
releases instead).

That leaves the continuous component of the sound.

Here is a java applet of the necker cube in perspective, so if one can get it to flip, it
looks really strange.
http://www.gifford.co.uk/~principia/Illusions/necker.htm

Robert

--- In tuning@y..., "Robert Walker" <robert_walker@r...> wrote:

/tuning/topicId_18416.html#18416

> Here is a java applet of the necker cube in perspective, so if one
can get it to flip, it looks really strange.
> http://www.gifford.co.uk/~principia/Illusions/necker.htm
>
> Robert

I really love these visuals... Finding the musical equivalent of
these would, indeed, be quite an accomplishment... From reading the
exchange, though, I'm not quite certain that it has been determined
EXACTLY what it would be. Either that, or I'm missing something in
the discussion...

Oh! I guess in a rather simplistic way, even the various resolutions
of a simple diminished seventh chord (in 12-tET) might fit this kind
of "multiple Escher" category... (??!)

Thanks!

_______ _____ _____ ___
Joseph Pehrson

jpehrson@rcn.com wrote:

>
>
> I really love these visuals... Finding the musical equivalent of
> these would, indeed, be quite an accomplishment... From reading the
> exchange, though, I'm not quite certain that it has been determined
> EXACTLY what it would be. Either that, or I'm missing something in
> the discussion...
>

I often use the analogy of visuals such as these to teach students how to listen to and to
play complex rhythms and to incorporate syncopation in their improvisations. I'm talking about
perception and awareness of stress here. You can play passages of Bach's cello or violin
sonatas in rhythmically different ways so that the pattern pops up on or off the beat. For
example the E major violin prelude or the arpeggio passage in the Chaconne. I would like to
hear more about how the visuals relate to harmony and tuning.

--- In tuning@y..., Alison Monteith <alison.monteith3@w...> wrote:
>
/tuning/topicId_18416.html#18537

> I would like to
> hear more about how the visuals relate to harmony and tuning.

Hello Alison!

Thank you for your commentary. Frankly, I think there are more
examples of this kind of Escher/Necker phenominon in music than one
might initially suppose. I think even something as simple as the
multiple resolutions of a diminished-seventh chord in 12-tET
(probably in some other systems also) would be a good example of this
perceptual "multiplicity."

I think you will see from the commentary that Robert Walker has
something specific in mind, a kind of "morphing" effect of timbral
change created by mixing the partials of one timbre with those of
another and then fading the initial ones out... so that the
resultant timbre changes before our very ears, so to speak. I
believe Robert is working on some further examples of this, so you
should have something to hear shortly...

_______ _____ ____ _
Joseph Pehrson