The SQ-64 is Korg's first Sequencer since the SQ-1 - which came out the same time as the MS-20 mini and was a simple 8 step analog affair. The SQ-64 is an altogether different beast.
It appears to take it's inspiration from the 3 melodic tracks and a drum track, like Beatstep and Keystep Pro from Arturia, but the way it addresses the steps and tracks is different.
There are 64 step buttons (each track can have up to 64 steps) which makes for easy.
Tracks A,B and C are for melodic/chords tracks and all have GATE/CV and MOD control voltage outputs for modular gear (monophonic) using MIDI, you can get up to 8 notes per step.
These tracks each have Gate, Pitch and MOD sub tracks - with modes switched via dedicated buttons.
Parameters for tracks A-C CV out can be: Hz/V, 0.26V/oct, 0.32V/oct, 1V/oct, 1.2V/oct - with voltage bias adjustment and 0V reference note adjustment (per track)
Gate out: 10V, 5V, V-Trig, S-Trig
Mod out: 0V-10V, voltage bias adjustment
Track D - the drum track has 16 possible tracks, via MIDI with 8 drum trigger outputs for working with modular gear.
MIDI is handled via a MIDI input and 2 MIDI outputs on Minijack Type A connections (not supplied)
Gate CV Per Track: V-Trig, S-Trig (global track: 5V, 10V)
Power is handled via micro USB (500mA gives lesser LED brightness, 2A full) or a 9V power input (not supplied).
You also get Sync in and Out on mini jacks, for hooking up to Volca's and other sync supporting devices.
Recording can be done from external MIDI input, though you will need to switch MIDI channels on the transmitting device to address each track, there is no specific track arming, you just record what you want. Or you can use the step input mode by switching the pads into Keyboard mode (no velocity) with various scale settings. I preferred using the external MIDI tbh, but for some reason track D (drums) will not record from external MIDI.
The advantage of recording from external MIDI is that you can record unquantized, so setting a step length of 1/4 note (32, 16, 8, 4, triplets available) and having a pattern length of 64 steps gets you 16 bars unquantized recording which is cool, however there is no way to quantize a pattern after recording it, unless you go to each step and change the offset value for each one.
Particularly for beats, the step editing is pretty comprehensive, with the Offset, Gate length, Probability and Ratcheting (Step) all easily accessed for the currently selected step(s), and dialed in on the four knobs.
It's the easiest way I've come across this level of editing detail and it really makes beats programming slick. I like it.
Other pattern parameters are step offset - where you can dial in the step offset to shift the notes from step one - another useful way to create variations. Swing can be global or per track.
Tracks A,B,C can also be set as Mono, Poly or Arp - this provides a sort of tempo based flam or strum for the notes in a chord on a particular step - its not really a full Arpeggiator which would be nice to have.
Loop Mode Another useful feature is being able to select steps or a range of steps and have those only play also at varying playback rates - this is neat as you can also choose to have this all work In-phase so that it will all snap back into time when you deselect. Another useful creative tool
Pattern Selection/Chaining When in this mode, you can cue up the next pattern to play from a list of 16 per track (corresponding to the step buttons) - this can be quantized to Pattern, Bar or Step. This is really powerful and again a neat way to arrange on the fly. However I did find that there was some wonky behaviour when switching patterns that were set to differing step and pattern lengths, when set to Bar snap, I got some odd offsets between tracks that threw everything out of whack, but I couldn't figure out why it was doing that. I'm sure they will be working hard to sort this out ASAP as it's a shame it's a little unpredictable.
You also are able to copy/paste clear patterns from this mode.
However, there is also a pattern chaining mode (shift + pattern). You can assign a pattern to up to 16 slots per track and it will play through in a song mode and loop to the start again - perhaps not long enough for an opus it's an elegant way to chain and again simpler than I've seen on other sequencers.
Controller Mode Dedicated mode where all 64 buttons are set to note values and four banks of knobs can be assigned to controllers - though this editing is not yet possible, there is an editor on the way, so it will certainly be of use to many, it's of limited use right now.
While we're on the subject of controllers, the USB MIDI gives you MIDI in ports from the external MIDI in and SEQUENCER output, and ports for MIDI out MIDI out 1, out 2 and SEQ output too.
Tracks can be assigned to USB, MIDI port (1 and or 2) and MIDI Ch.
One thing for sure, the SQ-64 offers an immediate way to create and edit sequences on the fly, but also to interact with the steps once they are written - I really like the easy access to the trigger probability and ratcheting, in combination, you can create some evolving and inspiring patterns, particularly when working with beats, it's just a shame we can record the initial pattern in from an external MIDI device.
There are a lot of configuration options and its likely that SQ-64 will fit your requirements, assuming that you are looking for a hardware sequencer.
I'm first to admit that I'm not really a step sequencer person, but the SQ-64 seems to have opened the door for me into a new way of working that is pretty appealing.