There is not any direct Voice compatibility with FS1R.
The FM-X has some similarities to all Yamaha DX/TX engines, but there is no Voice compatibility with FORMANT SHAPING (FS1R) Voices.
Voices from DX7, DX7mkII, TX802, TX816 have been announced as compatible with a conversion application.
FS1R it was a 16 Operator FM rack synth running on 8 Operators (Voiced) made musical tones, plus 8 Operators (unVoiced) made articulate noises.
The FM-X engine of the Montage features Spectral Forms which are best heard to appreciate the difference.
A Sine wave is the definition of the Fundamental containing no harmonics (overtones). Harmonics are whole integer multiples of the fundamental frequency. In DX-style FM you build increasing complex wave shapes by the interaction of sine waves. When the pitch of one Operator is uses to modify another is your basic FM. When the pitch ratio of one is 1:1 (equal) to the other, you get a result that is all the harmonics. When that ratio is 2:1 Modifier to Carrier, the result is every other (only the odd numbered) harmonic.
All harmonic we identify as a Sawtooth Wave
Every other harmonic we identify as a Square Wave.
FM-X gives an option to select "All" harmonics (sawtooth like), just "Odd" harmonics (square like) and spectral shapes with a resonant peak (emphasis) ... These non-Sine wave sources can be further strengthened via a parameter called the Spectral Skirt which influences the timbre of the resulting non-Sine wave source. You are provided 6 alternate wave sources of differing harmonic content (source waves) - which allows extremely complex waves from any single Operator... And there are 8 Operators per FM-X Part
An "All" (harmonic) Spectral Form with a Spectral Skirt set to maximum (wide) will give you a Sawtooth Wave.
An "Odd" (harmonic) Spectral Form with a Spectral Skirt set to maximum (wide) will give you a Square Wave
A "Res" (resonant harmonic) Spectral Form provides increasing higher frequency emphasis and a selection of complex synth sound sources.
These Forms in conjunction with the Skirt parameter generate the same type of energy with a single operator as a Feedback loop on itself would (except with a lot more control)... The classic single Feedback Loops found in the 88 algorithms ensure compatibility with legacy DX/TX FM sounds. But building sounds from scratch with FM-X you can start with a complex wave.
Significantly the resulting array of harmonic complexity as a starting point far exceeds the selection of a handful of wave types in your traditional analog synth. And once you start interacting this singular wave source by modifying or allowing it to be modified by another Operator, you begin to see there is truly an infinite range of wave sources per FM-X Part.
In the 1980's FM was seen as difficult. Back then the DX7 introduced menu driven interface. Using a computer was still new, navigating parameters and numbers in a screen was completely New. Now with everything from games to cell phones, navigating an operating system is literally child's play. Add to this the knobs and sliders that help adjust FM levels and settings... This time around FM will be a lot easier. The reputation of being difficult or hard to use will be greatly reduced. Time is always the best teacher. Everyone is very used to navigating and accessing parameters (this was completely foreign for most in 1983).
First, there are no Voices in the Montage, what you know as a Voice is now one of eight PARTs that can simultaneously be under Keyboard Control, a PART can be AWM2 or it can be built from an 8 Operator FM-X.
Each Operator has a source wave, and an Amplitude Envelope Generator which controls its output over time, and each Operator is either a Modulator (influencer) or a Carrier (outputs sound). Once the Operators have interacted to generate a complex output (sound), that sound can run through a Montage Filter (LPF, HPF, BPF, BEF, Dual band Filters, Etc., etc., etc.) Effects can be added, controllers assigned. Filtering, Effects and Controllers are assigned on the PART COMMON level of editing.
EG Bias was how, in the original DX-FM engine, you were able to additionally control the Amplitude Envelope Generator within each Operator via the Mod Wheel, Aftertouch, Foot Control or Breath Control. Normally a Program is activated by the Note-On key velocity, that determines the amplitude, and affects the resulting envelope loudness contour. The higher the key velocity the closer the output moved toward the main channel volume setting. EG Bias is a method to add to or replace this function with a physical controller.
Since in FM, the AEG is encased within each Operator - this differs from the analog synth paradigm where all oscillators likely share a single Amplifier Envelope Generator - individual control of the response of Operators allows multi-dimensional control within a sound. For FM, this means you can change harmonic content by manipulating 'modulator' output level independent of the 'carrier' output level.
When the FM engine is encased in a host synth, that host has access to the FM engine at very critical points. The FM-X engine can be accessed with the architecture of Montage. You can 'bias' control of Operator EG on a per Operator basis, from a long list of potential control sources (40 in all), including all the usual suspects (Mod Wheel, BC, FC, AT) and new possibilities like a Motion Sequence, the Envelope of another signal, even an external signal... so an external audio signal can be used as a control source to an FM-X Operator.
