Neither video clip features a vocoder. A vocoder actually takes your vocal input and encodes it on the synth sound.
The device used in the videos is called a Talkbox... which works much like a jaw harp, where you shape the sound with your mouth cavity (make sure your fillings are tight)! Audio is fed into you mouth via the tube, you ‘shape’ it with your mouth.

These devices are often mixed up. Do a search for Talkbox.

Thanks Bad Mr. that’s good information re TalkBox.

Can I get an answer to my other question, which was:

Is FM-X on a Montage capable of producing any sound that a Moog Little Phatty can make? It appeared that might be the case from the audio circuit diagram in the Little Phatty manual.

I don’t know how I could possibly know that... really.

OK, sorry for the over-broad question. Let me try to ask a more specific question.

I’ve attached the audio circuit diagram from the Little Phatty manual. It looks like a simple 2-oscillator FM-X algorithm to me. I could easily set up something like this in my Montage.

Do you see anything in this diagram that I might not be able to do in FM-X on my Montage?

You cannot exactly model the behavior of the oscillators. You can try - but the oscillator "fingerprint" (response, imperfections, waveform shape, change over time / temperature / etc) is not shown in the simplified diagram.

Pure FM doesn't do the right hand past the summation. The filtering part. FM-X has some filtering capabilities. Maybe some of the new effects can get you closer to the same "character" in the filter. But filter + amp has its own characteristic behavior that's not easily replicated.

If you buy a talkbox - then you may be able to run "Moog" presets through it and get there easier than programming an FM-X. In fact, you could probably run a hairdryer (hyperbole) through a talkbox and get pretty close to the same sound. The talkbox is doing the heavy lifting here. Guitars through a talkbox sound very similar - so it's not the fundamental so much as the modulator (your mouth's changing shape) that does the heavy lifting here.

Talkboxes and the DX100 have a celebrated history of pairing. And FM-X serves as a capable "replacement" of the DX100. FM-X having many more bells and whistles. So I think picking up a talkbox as an external effect can get you all the way there and there are plenty of Performances that can be used.

Do you see anything in this diagram that I might not be able to do in FM-X on my Montage?

I see the typical block diagram of an analog synthesizer based Voltage Control, I’m quite sure you are aware of the digital nature of the FM-X engine and that the fundamental building blocks of an FM engine are quite different. The FM engine feature an Operator structure which includes both the Oscillator and the Amplitude Envelope Generator.

The Operator (oscillator) includes the sine wave generator, an Amplifier, an Amplitude Envelope Generator, and inputs from other Operators and the keyboard. This is different from the typical analog signal flow - because the Operator includes the EG as apart of this single block - each tone source has its own Amplitude Envelope. In your typical analog synth, the Oscillators all share the same AEG.

In FM-X you have eight Operators, which immediately allows for more detail changes over time. And because the basic FM engine did not include a Filter, it is this detailed control over the Modulator’s output over time that shaped the timbre change in traditional FM sounds. Integrated into the FM-X engine is access to the 18 resident a Filter Types, and of course, the recently added VCM Mini Filter and VCM Mini Booster which are routed to as Insertion Effects.

In both cases the routing is from the Oscillator through the Filter (be it the resident 18 Types, or to the Insertion block). The Filters receive the completed FM Waveform — so it is very similar to how the oscillators in a typical analog synth sends all of its Oscillators through the same single Filter (unlike AWM2 where each Oscillator has its own dedicated Filter).

So allowing for the different signal flow you can go about emulating the analog sound with either the FM-X or the AWM2 engines.
You results will be a result of experimentation. Naturally there are going to be some differences - how important they are for the sound you are making will depend.

The synth sound source for a Talk box is really less important than you might think. It depends on how much intelligibility you want. What is typically favored is a smooth clean synth lead tone (lyrical)... you will develop your own preferences based on what you like.

The reason I was reluctant to answer is because of how basic the synth sound usually is — I don’t want to be involved in a discussion about things Analog can do that are uniquely analog — especially because none of them are in evidence in the examples you posted. A Vocoder is very different from a Talkbox... they both involve a microphone and a synth, but one you actually have use your vocal cords (vocoder) and the other you do not (Talkbox).

Once you have worked with a Talkbox you’ll perhaps understand how much of what you hear is contributed by each device and how much is contributed by your mouth cavity! I think that will answer all your questions almost instantly.

As a final note, truly FM-X is still an open book... new sounds can be developed in this system. And FM-X (as found here) is the most accessible FM engine ever. You can anticipate being able to create most any sound... having eight 8-Operator synths (when you setup for TX816 type programming) and then add the interactivity afforded by the Super Knob, plus the VCM models of the MIni Filter and Booster...

BTW - one thing that makes an analog keyboard such as the Moog referenced is the control and how those controls shape the sound in real-time. I didn't cover this aspect because I didn't see the video clip that the keyboardist was riding the knobs. I saw one time when some knobs were turned to slightly alter the sound - but no real "knob riding" where the sound is morphing constantly. So this therefore lends itself fine to the hairdryer. Just pass any sound into a talkbox and you pretty much have it.

I reference the DX100 because there's lots of resources out there of past talkbox masters using keyboards and preferring the DX100 due to, primarily, its simplicity to program vs. others in the DX line. You will find lots of talkbox + DX100 material out there to reference which includes generalizations of what types of "patches" to use (operator configurations - i.e. waveforms and such). FM-X can handle all of this. If you really want that sound I would strongly advocate getting a talkbox.

I'm not sure what formant manipulation could have done if fs1r capabilities were inside Montage. There's an effect with some formant manipulation (Talking Modulator) - but it doesn't seem to allow very extreme settings. Nothing like a true talkbox. Which is why there's such a push for you to get a talkbox if that's the effect you're after.

...

Thanks, Bad Mister and J. That’s just the kind of information and perspective I was looking for!