> First read this:
>
> http://www.sospubs.co.uk/sos/1997_articles/jul97/ronberry.html
>
> He has supposedly built some of his own devices
Just checked this; I have seen it before, But I didn't remember the name.
This goes into the right direction, but it has one drawback:
The feedback loop is only around the delay line.
For more natural emulations (or for more interesting new
creations) you want all kinds of filters and nonlinear operations
inside the loop.
The problem with such extra devices inside the loop is that
you cannot play "in tune" anymore. It still works with
perfectly tracking filters inside the delay loop, but this doesn't
help much. On a real instrument, it's a difference whether you
just change the length of a tube, or if you have keyholes
openend etc. So you want a mix of tracking and fixed filters
inside the loop at least. You cannot move the formants
(fixed stuff) out of the loop either, because they interact with
nonlinear stuff inside the loop, such as air flow rate saturation.
The direction in which I'm presently thinking is like this:
To make a set of modules for the delay and for the nonlinearities,
which could then be patched together with ordinary synth modules
(like a LPF for the stiffness of a reed etc.). If you patch them together
your tuning will be a mess. But then there must be an "overhead
module" which performs an autotuning routine (think of a
synth with very bad VCOs ...) and creates a large table to correct
the pitch CV.
You would go
(1) patching whatever you find reasonable and what
will oscillate, and which produces interesting higher modes
when you change a "pressure" CV or something like that.
(2) You set your "pressure" and other performance parameters
to their nominal value and press "autotune" on th overhead
module.
(3) Afterwards, you can play this model you have created
perfectly in tune (when your performance controls are
at their nominal values), and you can go into the "wild
other modes" just as your self-built model allows.
What I like about this idea: You don't have to care about
tuning, so you have ∗every∗ degree of freedom to patch in
any existing module you like - everything that closes the
loop and gives controlled oscillation. And all this with only
2 or three new modules (delay line + autotune unit could be
in one module; and a good reed simulation would be a
second new module.)
Only thinking aloud at the moment. Spent a good part of
last night with Yamaha patents and VL7 manuals - I finally
begin to understand that stuff.
JH.