I’ve uploaded another example instrument, 4 op FM mix, into my iLocker 241 folder. (you have to navigate to the 241 folder, inside of BSU_SHARED) You can also download the FM operator sub-patch as a separate file.
The instrument is the basic one I’ve been using in class – two modulator-carrier pairs, with a pitch envelope and lowpass filter. The presets should be the most help, and I’ve outlined their important features below. Please take a look at this instrument and presets. I’m going to demonstrate it, and add a little more to it in class on Friday.
bell attack saw sustain
I’ve been using this idea for a while now, with the first modulator-carrier pair (row1) set to an inharmonic ratio of around 1.4:1, and the second m:c pair (row2) set to a harmonic ratio of 1:1. The first pair handles the attack, and the second pair is the sustain, which is done by setting the Vadsr envelope modules for each operator. The second pair of oscillators is slightly detuned, creating beats. The pitch envelope gain is set to 0, and the filter cutoff is at max high, so neither module affect this preset.
saw attack bell sustain
This is just the reverse of the previous preset, achieved by swapping the envelope settings for the two pairs of operators. Unfortunately, you have to do the swapping dial by dial.
Percussive xylo is based on bell attack saw sustain. The bell attack portion of the patch (row1) is shortened by shortening the initial decay time of the envelope generator. The saw sustain portion (row2) uses similar envelopes, with short but slightly longer initial delays than the top row. None of the envelope generators have any sustain. A slight amount of pitch bend is added to the instrument by turning up the pitch envelope gain control.
double sustain bell
This is a variation of the bell patches as well. In this case, the top row bell is set to sustain envelopes (longer attack time, no initial decay, full sustain level). The bottom row is set to an inharmonic ratio of 4.45:1, which provides more higher partials than the top row, and the partials have more space between them. The second row envelopes are similar to the top, but with slightly longer attack times.
double sustain bell with filter
Everything is the same as the previous preset, except that I’ve set the lowpass filter to have some effect on the output. You will usually want to use pitch output from the keyboard to control the cutoff frequency (which I have done). But I haven’t set the modulation input gain on the filter to track the keyboard pitch at the same rate as the oscillators do. The mod input gain is higher than normal on the filter, which causes the filter cutoff frequency to rise faster than the keyboard going up from middle C, and get lower faster as you go down from middle C. This setting tames the overly bright nature of low-pitched sounds with FM synthesis in a more natural way than just creating separate low and high presets. Compare the low notes in this preset to the low notes in the double bell sustain without the filter.