The routing you’ve described brings up some interesting options. Many upstream effects – compressor/freeze, tremolo, deep flange, reverb, delay – add their own ‘envelope’ overlay on to your signal. The H9 modulation further downstream can use these amplitude variations to control its own effects.
It’s a modernized version of routings available in some classic rack FX [like the Lexicon Vortex preset emulation here].
This somewhat unrelated image still illustrates the basic concept: Your delay line brings a decaying envelope over your signal; chopped into discrete echoes. You can use this envelope to create changes in pitch modulation depth & rate of effect.
Primary pitch modulation uses the smoother SINE LFO. It’s sync’ed to eighth notes over MIDI, and panned wide. The secondary modulation is controlled by incoming ENVELOPE. A hefty amount of DEPTH MOD and SPEED MOD means that changes in amplitude will translate to depth & rate variations in the primary SINE wav sweep.
You can think of MOD SENS here as the maximum limit on the primary DEPTH and SPEED. Try varying the value of 35 here to increase / decrease what will happen at the input’s loudest point. The same rules apply to balance INTENSITY and DEPTH for the desired effect.
The expression pedal is set up as a sub-mixer. WIDTH is shifted from wide to narrow, and INTENSITY of effect is reduced. In my mind, it’s more accuate to look at WIDTH in terms of the phase between left & right SHAPE waveforms. A value of 99 puts them 180 degrees apart, and moving towards 0 shifts them more in-phase with each other. As an example, change the SHAPE from SINE to SQUARE, then adjust the WIDTH control. It’s easier to hear the rhythmic shuffling of modulation.
This preset is also another good candidate for SLOW/FAST performance switch variations.
My H9 is placed at the tail end of the pedalboard as a special effect toolkit. Most of my time-based effects are after the H9 in the rack / line mixer. But upstream, I do have an AdrenaLinn III, Philosopher King, EHX Freeze, PitchFactor, etc. that can feed it some effect-based envelopes. As an example, here’s a bog-standard delay preset that I route into the H9’s Vortex Reflexion preset.
Louder delays come into the Vibrato algorithm, and force faster and deeper SINE modulation sweeps. As the delays start to decay, pitch modulation becomes shallower and slower. Later repeats will ‘clean up’. While it’s not producing a true ping-pong type of delay, every other repeat will be reinforced in both L&R channels.
The only unconventional thing about the H910 / H949 preset here would be that the pitch shifter model TYPE is being swept by the expression pedal. Both FEEDBACK controls increase to maximum at the same time. PITCH is at unison, so TYPE shifting will only inject some glitchy artifacts into the decaying repeats. It breaks up the echo loop in interesting ways (to me, anyway).