Arturia released AstroLab 2.0 on October 6, a free firmware update for its AstroLab stage keyboards in 37-, 61- and 88-key versions. Among the headline changes is "better aftertouch response." That is a good moment to clear up a common confusion: aftertouch and MPE pressure are related, but they are not the same thing.

What is in AstroLab 2.0

Per Synth Anatomy's review, the main addition is a Sound Edit menu, a new layer exposing parameters for every instrument. Depth varies by engine: Mini V4 gets basic filter controls, while MiniFreak V offers access to most of its sound engine. The update also brings new sampled instruments (piano, brass, strings, bass), 67 new factory presets, improved polyphony for the sampler and Synthx, an octave LED transposition display and refined computer-to-hardware communication.

There are limits: custom SFZ multisamples cannot be loaded, and two V Collection instruments, Memory V and Sub Bass, are due in later updates. The firmware is free for existing owners. Details are on Arturia's website.

The review mentions the aftertouch improvements but not full MPE specifications, so we will treat this as an aftertouch story rather than an MPE one.

Channel aftertouch: one value for all

Most keyboards that offer aftertouch send channel pressure: a single pressure value for the whole MIDI channel. Hold a chord, press harder on any key, and the receiving synth gets one number. Every note in the chord is affected equally.

That is perfectly useful. Adding vibrato, opening a filter or swelling a pad with a single gesture is natural, and it is the reason aftertouch has been a staple of keyboards for decades. Better response means the curve feels more predictable, so small movements give fine control instead of sudden jumps.

Polyphonic aftertouch: one value per key

Some instruments send polyphonic key pressure, a separate message for each note. A chord can have different pressure on each key. It is richer, but support on the receiving end is less common, and many plugins ignore it.

MPE pressure: per-note, on its own channel

MPE takes a different route. Each note is placed on its own MIDI channel, so ordinary channel pressure becomes per-note pressure without any special message. The same trick gives each note its own pitch bend and its own slide (CC74). The result is three independent dimensions per finger, plus note-on and note-off velocity if the controller supports them.

This is why MPE works with so many existing synths: it uses standard MIDI messages in a clever arrangement, as laid out in our guide to what MPE is.

Which do you need?

Choose channel aftertouch if you play a conventional keyboard and want one expressive gesture across a patch. It is simple and widely supported.

Choose MPE if you want each note in a chord to behave independently, for example gliding one voice while holding others steady, or pressing a single string-like note to brighten only that note.

The two are not rivals. Many players use a keyboard with good aftertouch for general work and an MPE controller for solo lines and expressive parts. Improving aftertouch feel, as AstroLab 2.0 does, makes the conventional route more rewarding.

Takeaway

AstroLab 2.0 is a generous free update for existing owners, with deeper editing, more sounds and smoother aftertouch. For MPE fans, it is a handy reminder that the pressure you feel under your fingers can mean different things depending on how the instrument sends it.

Sources: Synth Anatomy review, Arturia.