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.