Tuning the Flute
So, how do you go about
tuning a model with two independent delays?
If you go the SeqCtr route, do you really need two sets of SeqCtrs, one
for each pipe?
Not really. If we just link the pipes together and tune
them simultaneously, we can get satisfactory results. A tuned flute patch is below.
The SeqCtrs operate the same
way they do on the blown pipe patch.
We’ll use the same tuning method, too.
Beginning with C2, we’ll tune every C, E, and G#. The lights on the SeqCtrs will indicate which
sliders to adjust.
Tracking the loop filter from the
keyboard
You’ve probably noticed that
both the pipe and flute models sound “clarinetty” when playing low notes. This is because the lowpass filter in the
bore loop has a fixed pitch, 8.37 kHz in this model, and lower notes have more
harmonics that pass through the filter.
Since both of these models are basically square-wave generators that create
odd harmonics, low notes sound kind of “woody”.
If this is undesirable, we
can always use a tracking lowpass filter to get rid of these harmonics. But there’s another, more elegant
possibility: when playing low notes, we can lower the frequency of the lowpass
filter in the bore loop. This also will
make the sound mellower, without requiring any extra EQ.
So we’ll try this. Since high notes don’t need any adjustment,
it would be nice to be able to adjust the filter at periodic points along the
keyboard. Again, the SeqCtr comes to the
rescue, letting us adjust the filter’s frequency at each fourth note. And there’s a precedent for this: the VL1 has a piecewise-linear adjustment
table for its “Absorption” parameter, which is its name for the filter cutoff
frequency.
But there’s a catch: changing the frequency of this filter will
change the instrument’s tuning. And
that’s why this discussion is here, on the “Tuning the Flute” page.
Below is a patch that lets
us adjust the filter along with the tuning.
When doing this, the best procedure is to adjust the lowpass filter’s
frequency at the same time that the pitch is being adjusted. Simply adjust the filter’s cutoff frequency
until the desired timbre is reached, and then use tune the delay to the proper
pitch.
