Excellent. And excellent topic. I’ll start by saying (my standard disclaimer) there is no one way to proceed.

Configuring a setup that permits you to perform live is a very personal thing... in general, communicating with your audience (anyone listening) is what you are going to be primarily concerned with... and audiences ‘use’ your music for various things (background, serious listening, dancing, etc., etc.) You use it as a creative release...

So you’re going to deal with what things are going to be fun and entertaining for both parties. Recording the drums live, you’ve said, is not a priority for you.
Therefore, you will spend some amount of time pre-producing your Drum Tracks. The advantage of pre-producing your drums is you can have a more detailed *arrangement* in every sense of the word. Those that record the rhythm stuff live (as apart of their performing) usually approach it from the “looper” mentality. You add items and let it spin... (over and over...)

With any creative process, a lot of the work takes place behind the scenes. When you see any musician perform, the listener is, to greater or lesser degree, aware of the blood, sweat and tears that the musician must have put into perfecting their performing skills. Unfortunately, with electronic music performance, the audience loses many of the standard reference points they use to make such judgements.

When you play a synth or have a computer involved in your performance, you do yourself a disservice if you don’t “let them in” on what you are doing. If a sequencer is involved — if you don’t say, many listeners will assume you are playing along with a tape or CD or something. They may discount your role in the creation of what they are listening to... (akin to how they look at lip sync’ing) this may not matter at all, but it may setup an unspoken barrier between you, as artist, and the listener, your audience. They are wondering now how much of this is you and how much is the electronics (it happens because they don’t know what they are hearing or how it is being made). Which is okay, we mention it because it exists (some times).

I just mentioned this because, the concept of the Drum Arp Phrase in the MODX lends itself to drum track preproduction. You literally, assemble the drum track, offline, ahead of time. Time consuming? Yes, absolutely. Necessary, however, to at least some degree.

Arp Phrases can be accessed live
Arp Phrases can be transferred to the Pattern Sequencer.
The significance here is how you can access them. And what you can do with them.

If you are planning on recording in a live performance situation, realize that recording, when optimized, is very much a start-stop—rewind-start-stop process. Recording music in front of an audience winds up limiting you to LOOPER-ville... where you sacrifice the accuracy and detailing available in the start/stop method for the compelling momentum of non-stop loop creation.

It’s like performing as an actor.... if you’re doing a tv sitcom in front of a “live studio audience” versus doing a Broadway play.
The live studio audience is apart of the creation, and are made to feel that they are participating in creating the show... in exchange for all the multiple takes they must sit through (laughing each time)... contrast that with attending a theatrical play, where the audience is not a ‘studio’ audience (participant), but get to play their traditional role, as the (non-participant) “entertained”.

I’m reminded of artists who create a painting in real-time, in front of an audience. Their challenge is they have to have a sense of what is entertaining, what is it that is going to be interesting for the audience to watch them do, versus, just showing a finished product.

What portion of the music creation process do you wish to share with your audience? (Programming the bass sound in real time, is probably not going to be as engaging to your audience as writing/composing a funky bass line over a looped drum groove)...

In all cases, the attendees are thrilled to be there... the musical equivalent is the topic here. How do you want to include them?
And only you, the performer, can decide any of these things. What follows are some examples (experiments I’ve tried)...

Drums
With the Motion Control synths you have an option of running external audio into the synth engine. This means not only can you “play along” to it, you can actually have it interact with the synth engine... not only providing tempo for your arps, effects, LFOs, etc, but as a modifier that can be used to interact with synth sounds you are playing.

Recommendation: one of the premiere drum track creation tools (on this planet) is “Groove Agent” (Comes with Cubase as a plug-in)
Learning Curve — relatively short. Tons of video support online.
Full track creation — less time consuming
Let’s you fashion drum grooves, automate fill-ins, change intensity, etc
Setup and jam with it — once you solidify your drum concept you can render it as audio. Use the computer as a pre-production tool to create your drum track. You can fashion absolutely professional sounding drum grooves, with all the fill-ins etc.

This way, even if you don’t want to perform with a computer, you have created a complete drum track - (as a .Wav file) you can play it from an audio device through the MODX AD IN

Live Looping
You’ll have to experiment with the Pattern Sequencer. It can be made to Sync with tempo arriving via AD IN

Using Playback Length: the LENGTH (the number of measures set for a Scene to Loop) is dynamic when you are playing back. What this means is... say you record or Append several musical sections into SCENE 1... say a total of 48 measure long
You could initially have it play Length = 16. It would repeat just the first 16 measures over and over...
On the third time through you can change the LENGTH = 24, allowing additional measures to sound... thus revealing 8 additional measures to the Loop Length.
In this manner each of the 8 Scenes buttons can have “hidden” measures that you reveal by manipulating the LENGTH while playing back.

I use this often. I’ll have an 8 measure Length for verse Scene 1, let it play twice, then I change the LENGTH 24 which reveals an additional 16 measures (the Chorus)... before returning measure 1. By dynamically changing the LENGTH, I can reveal the Chorus at any time. Thus creating an AABA format whenever I desire... And all from one Scene button.

In SCENE 2, I have a variation of the 16 measure Chorus, with another 16 measure of the Solo section ‘hidden’ beyond that. This way, with Scene 2, Length 16 I can repeat the Chorus as many times as I need, and then move to the Solo section.

In Scene 3, I have a variation on the 16 measure Solo section, followed by 32 measure of the vamp... and so on

In this fashion I am able to vary the structure of the composition in real time. I have the Verse (8 bars) at the front of Scene 1
I have the Chorus 16 measures attached to Scene 1.
The Chorus is also the front of Scene 2, with the Solo section attached.
The Solo section is also the front of Scene 3, with the whatever else attached ... and so on.

This gives me creative re-arrange capability while Performing.
You do need to be on the Pattern screen while working the LENGTH setting live, so you will learn to prepare your front panel access to the sounds via the left front panel “Quick Edit and AssignKnob” functions.

Anyway, that’s just an example of one possible workflow. You will need to decide if actual recording is something you want to do live and how you move from record to playback — based on what you want do. Large modular rigs where you are interacting with various Looping components, is another whole area to explore. The Motion Control Engine has a variety of ways to bring together various musical components referencing its clock.

As mentioned, external audio can be used as a clock source, and that audio can interact with your synth engine. Here, I’ve experimented with feeding audio (drum/percussion loops) into the AD IN, at times I use their audio direct, at other I use them to create Envelopes for my FM-X Operators to ‘Follow’ — so these intense rhythmic patterns vary the Element Level of the Modulators in the Pad sound I’m playing.

By disconnecting the audio output, I re-route the audio energy into the Motion Control Engine where it becomes a modifier. Sometimes you can have both signals... a mixture of the audio and at the same time have it pulsing through your keyboard sound.

In the Motion Control Engine, once you open the door to the possibilities of Side Chaining signal (where the output of one device is routed into another to apply some variation of the resulting sound) — well, let me say, it is one of the deepest of all the programming rabbit holes.

Each is a snowflake (I’ve spent hours exploring some of the more intricate Performances) - often when thinking about performing, often the build up of components (one by one) can be an effective way of drawing your audience into your music. For example, if you just press a start button and everything plays at once - it has a different impact on the listener from bringing components in one or a few at a time.

This is a subjective thing - but mentioned because you should consider it when attempting a one-person electronic performance.

I have to say that this response was more than I hoped for. Thank you for the technical info and the general tips regarding entertaining an audience! It will take me some time to experiment with the methods you've suggested, so I don't have any comments on them just yet, but I will report back once I do. I'm very excited to experiment with envelope follower and the playback length changes.

In case my experience is helpful for others, here's what I've experimenting with up to now (prior to reading Bad Mister's post), and my initial thoughts.

CUBASIS
After watching a Dom Sigalas video, I did do some digging into using Cubasis as a Midi sequencer for the Modx. I started by lining up three or four of the free drum loops (let's say 8 measures each) in Cubasis and setting the initial loop period to 8 measures. To change between the drum loops on the fly, I would just extend the loop period to the next 8 measures (this seems like the same logic as changing the playback length discussed by Bad Mister). Going back to an earlier drum loop didn't seem to be doable on the fly, as you would have to time your selection of an earlier playback point perfectly. Other limitations are that changing the loops on the fly required full attention and I couldn't simultaneously play a chord progression or bass line with the left hand, but I can live with that.

Once the drum loop was playing I would record enable Midi track 1 on Cubasis, and noddle around with a bass-synth and slowly allow the bass-line to become what I want to record as a loop. I like to think this process of not playing the notes that you want to loop right away may help the audience to see that you are in fact playing the instrument, as opposed to just pressing play. Once the bassline was looping, i'd stop recording the bassline and start tweaking the super knob and mod wheel to add more character to the bassline and when I had achieved the appropriate level of weirdness, I'd re-arm the bassline track for record on Cubasis and record the tweaking. I might add some strings, pad, or choir to the loop. Then I would solo with a synth lead. All in all, I found the integration between Modx and Cubasis to be very good.

The big problem with being in loop-ville as that once you've built up the loop, it's hard to move to the next musical idea (beat drop, chorus, etc). The best I could do is build up a dancey loop with lots of elements and then extend the looplength on Cubasis another 8 measures (where only my pre-programmed drums exist), and play a bassline. The other option is to slowly remove one element at a time until you're left with just one element from which you can build a new loop, but that gets a bit boring for the audience I imagine.

GARAGE BAND VIRTUAL DRUMMER
Creating drum tracks with GarageBand's virtual drummer was really simple. I recorded some song-length drum tracks in GarageBand and fed them into the A/D input and just played over them. The full drum tracks allowed for more variation in the songs than looping, but I could only have drums and two parts (left hand + right hand) at any given time, which is probably all you can ask for if you want to play live without looping I suppose. Another downside is that you don't have control of how many times you want to repeat a chorus or verse and are locked into whatever you programmed ahead of time.

Come to think of it, using GarageBand's looping view for percussion, combined with the Modx envelope follower, might allow for drum variation on the fly, while keeping the Modx in sync. I'll have to experiment...

NOVATION CIRCUIT
I also connected the Modx to a Novation Circuit, with which I am pretty comfortable. Connected the audio from the Circuit to the A/D in on the Modx, synced the midi clocks, and used the Circuit's internal drum tracks. I also sequenced midi tracks 1 and 2 of the Modx with the Circuit (which I dedicated to a bassline and chord progression), and was able to record loops and then solo a synth lead on top of that. This setup was the most intuitive for me, but that's probably because I have been messing around with the Circuit for years. The limitation is that programming complex drum beats is tough (easier to let GarageBand do it for me), there are only 2 tracks for midi sequencing, and I wasn't able to get Modx motion sequences to record onto the Circuit (so I could not get Super Knob or modwheel tweaking to join the loop).