Richard Geere posted an excellent Ensoniq VFX DS Demo video. The video covers the basic architecture of the VFX, along with demos of some of his custom sound design and VFX patch presets. At the end he also covers the layout of using the LCD to navigate editing presets with some nice tips.
Synth veteran Richard Geere demos the Ensoniq VFX-SD. Overview, original patches and programming section. This is a stereo synth - headphones recommended!
The VFX like many other Ensoniq keyboards are very fun to program, they are very deep instruments.
The filters do not have resonance which is unfortunate, but the synth features numerous preset sweepable wavetables called “Transwaves”.
Ensoniq’s synths produced after the VFX are not very closely related to the older ESQ-1 and SQ-80. They look similar, and the sequencer and UI is similar, but the architecture is quite different. The older synths have 3 digital oscillators per voice that (mostly) play static waves, with an oscillator sync function, through a single analog Curtis filter and amplifier. The VFX and subsequent instruments are completely DSP-based, with pretty good onboard effects as well. The voices are meant to be stacked, each consisting of 1 entire sampled sound or a Transwave, through a single non-resonant digital filter.
Overall the VFX is a very underrated synth so it's great to see someone highlighting and demonstrating it's capabilities after learning how to best utilize it's sounds and transwave oscillators.