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Message: [QUOTE="Bombastus, post: 92286, member: 2178"] Impetus 1.0 maps an MPE keyboard’s Y-axis Slide gesture to eight bankable DAW mixer faders on Apple Silicon Macs. The interesting part is not simply replacing a mouse with a finger. Impetus repurposes a stream of expressive performance data that MPE normally sends toward an instrument. On a Seaboard-style surface, moving a finger vertically along a key produces Slide data, commonly carried as MIDI CC74. MPE normally keeps expressive data tied to individual notes by assigning sounding notes to separate member channels. Impetus takes the movement in another direction, translating it into HUI or Mackie Control behavior so the DAW treats the keyboard as a control surface. [HEADING=2]MPE Slide starts as per-note CC74 movement[/HEADING] MPE did not create a new kind of MIDI message for vertical finger movement. Its specification uses familiar MIDI 1.0 messages in a channel arrangement that lets pitch bend, pressure, and CC74 affect individual notes rather than every note on one channel. ROLI describes Slide as vertical Y-axis movement, with CC74 as its default message. The value itself is simple. In ROLI’s Absolute Slide mode, the bottom of the playing surface corresponds to 0, the center to 64, and the top to 127. Relative Slide behaves differently because the initial touch starts at 64 regardless of where the finger lands, then upward or downward movement changes the value from that midpoint. None of those numbers inherently mean filter cutoff, brightness, volume, or anything else audible. A receiving instrument decides what the control changes, which is why one synth can map CC74 to a filter while another sends it somewhere completely different. The Seaboard sits in a broader family of [B][URL='https://www.mdpi.com/2414-4088/7/2/15']multidimensional music controllers[/URL][/B] built around gestures that can manipulate pitch, pressure, and continuous parameters in real time. Impetus exploits exactly this separation between gesture and destination. Instead of letting MPE Slide remain a per-note sound-shaping signal, it treats vertical motion as a physical input for mixer control. The gesture stays familiar, but its job changes from shaping a note to moving a DAW parameter. [HEADING=2]Absolute and relative motion change the fader feel[/HEADING] Absolute and relative control solve different problems when a finger becomes a fader. Absolute input gives the surface a positional meaning, so where you touch and where you move can correspond directly to a value. Relative input changes the existing value upward or downward from its current state. ROLI’s own Slide behavior makes the distinction easy to see without pretending every application implements it identically. Absolute Slide reports finger position across the Y-axis, while Relative Slide starts from the midpoint and measures movement around it. For DAW mixer fader control, those two ideas affect how quickly a parameter can jump toward a touched position versus how naturally it can be nudged from its current state. Impetus lists Absolute, Relative, and Hybrid fader modes, plus a Fine mode for increased resolution. Impetus has not publicly defined the Hybrid algorithm in enough technical detail to equate it with any standard MPE behavior, so treating Hybrid as application-specific is safer than guessing. Fine control matters for a simpler reason because a short finger movement needs enough usable steps to make small mixer adjustments feel intentional rather than twitchy. An MPE keyboard as a DAW controller is therefore more than a novelty mapping. A continuous Y-axis already gives your finger a variable control source, while Impetus supplies the translation layer needed to make the DAW interpret that movement as mixer control instead of instrument expression. Modifier keys can then redirect the same eight controls toward pan, solo, mute, or record arm without changing the underlying physical gesture. [HEADING=2]The gesture becomes control-surface data before mixing[/HEADING] With [B][URL='https://goldmidi.com/community/threads/impetus-software-has-brought-impetus-control-to-macos.77649/']Impetus control on macOS[/URL][/B], the important handoff happens between the keyboard and the DAW mixer. Impetus receives the expressive movement and communicates with supported hosts through HUI or Mackie Control, so the host sees a control-surface workflow rather than a plain MIDI remote mapping. Keeping those layers separate clears up a common source of confusion around MPE fader control. CC74 describes a continuous expressive dimension, but it does not dictate what a mixer must do with it. HUI and Mackie Control provide the control-surface side of the conversation, while Impetus sits between the two and decides how the gesture should be converted. The result is a useful split in roles. Your keyboard provides the physical Y-axis movement, MPE provides the expressive data convention, and Impetus redirects that motion toward eight mixer controls. Banking extends those eight control positions across a larger session, while the actual track volume remains a DAW parameter rather than an MPE expression value stored inside a note. [/QUOTE]

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