Hardware sequencers have historically been the weak link in an expressive rig. You can buy a controller that sends per-note pressure and a synth that responds to it — and then discover that the box sitting between them flattens everything into note-on velocity. Squarp Instruments has been steadily fixing that on the Hapax, and firmware 3.2 addresses the piece that was still missing.

A dedicated AFTR track

The headline change is a new AFTR track type that records, plays back and edits polyphonic aftertouch.

The significance is in how it is scoped. MPE requires a synth that understands channel zones; poly aftertouch does not. The AFTR track works with any synth that responds to polyphonic key pressure, over DIN or USB, without setting up an MPE zone at all. For anyone with older hardware that supports poly AT but was never going to see an MPE firmware update, that is a genuinely new capability rather than a convenience.

Each note carries its own pressure curve, and that curve can be drawn and edited directly in Step mode. Crucially, the curve is stored with the note: move a note, transpose it, copy it to another bar, and the aftertouch data travels with it. Anyone who has tried to edit pressure as a separate automation lane in a DAW — and watched the curves desynchronise the moment they nudged a note — will understand why this is the right design.

Pass-through on every track

The second, quieter improvement may matter more in practice. Incoming poly aftertouch is now passed through to the output on every track type, not just AFTR.

Previously, routing a controller through Hapax to a synth meant the sequencer would swallow pressure data. In a live setup where Hapax acts as the central MIDI router — which is exactly how many people use it — that made the box a bottleneck for expression. Now it gets out of the way.

Combined with the MPE work introduced in Hapax 3.0 earlier this year, the sequencer now handles both of the major per-note expression models without forcing you to choose a workflow around its limitations.

Clock improvements

Firmware 3.2 also raises the CV clock rate ceiling substantially. Where Hapax previously topped out at 24 ppqn, it now offers 48 and 96 ppqn. That is tight enough to sync Hapax to an audio-rate clock coming from a DAW or a modular system, which matters for anyone running the sequencer alongside a Eurorack case where timing slop is immediately audible.

A new Clock Timeout setting is a smaller but welcome addition: if the external clock disappears mid-performance, Hapax falls back to its internal clock rather than hanging. Losing a USB connection on stage is no longer a silent stop.

Poly AT and MPE are not the same thing

Worth restating, because the two get conflated: polyphonic aftertouch gives every note its own pressure value on a shared MIDI channel. MPE gives every note its own channel, and therefore its own pressure, pitch bend and timbre (CC74).

Poly AT is one dimension; MPE is three. But poly AT is far more widely supported on older and cheaper hardware, it uses a fraction of the bandwidth, and it does not require the receiving synth to understand zones. For a lot of sequenced material — pads that swell, leads that push into the filter — one well-drawn pressure curve per note is all the expression the part actually needs.

Having both as first-class citizens in the same sequencer is the useful outcome here. You can run an MPE track to a modern synth and an AFTR track to a twenty-year-old poly on the next output, from the same project.

Getting the update

HapaxOS 3.2 is a free firmware update for existing owners, available from the Squarp firmware page. As with previous releases, the changelog is worth reading in full — Squarp's updates tend to carry a long tail of smaller fixes alongside the headline features. Community discussion and installation notes live on the Squarp forum.

Further coverage: gearnews.