Use a Stream Deck as an expression / wah pedal

No expression pedal? MIDIRover lets you ride a parameter by hand from your Stream Deck — sweep a wah, roll back volume, or open a filter, live. It sends MIDI, so it works withNeural DSP and any MIDI-enabled plugin, on Windows or macOS, for free. There are two ways to do it: a dial on the Stream Deck +, or Sweep mode— hold a key and the value sweeps — on any Stream Deck.

What you'll need

• Any Stream Deck and the free Stream Deck app — a Stream Deck + if you want a real dial, otherwise any model works with Sweep mode.
• MIDIRover — this plugin.
• Windows: a virtual MIDI port (the free loopMIDI). macOS: nothing — MIDIRover makes its own port.
• A plugin whose wah / volume / expression parameter can MIDI-Learn (e.g. any Neural DSP wah or volume).

1. Connect MIDIRover to your plugin

Add MIDIRover to the Stream Deck app. On Windows, open loopMIDI and create a port; on macOS the plugin makes its own. Drop a MIDIRover action on a key and pick your MIDI Port (or leave it on Auto-detect) — the choice is shared by every key. Then set your plugin's MIDI input to the same port.

2. MIDI-Learn the parameter

In your plugin, right-click the wah (or volume / filter) control and chooseMIDI Learn. You'll press the Stream Deck control in the next step to map it — no CC numbers to look up. A CC learned to a knob or slider tracks your control directly — nothing extra to enable; if the sweep feels coarse, lower the dial's Step or set a Range.

3a. Ride it on a dial (Stream Deck +)

Add a MIDI Dial to an encoder and, with MIDI Learn armed in your plugin, turn the dial once to map it. Now turn to sweep the value; hold while turning for coarse steps; andpress or tap to jump back to a reset value (great for snapping a wah back to heel-down). Under Display, choose Knob for a rotary look, orKnob (ring from centre) for bipolar controls like pan. Set a Range to keep the sweep within, say, 20–100.

3b. Ride it on any Stream Deck (Sweep mode)

No dial? Add a Control Change action and set Mode → Sweep. Nowhold the key and the value sweeps through the range, bouncing at the ends, until you let go — a hands-free wah or volume swell on a Mini, MK.2, XL or Neo. Set Sweep timefor how fast a full sweep takes, and Range for the min–max. On a screen key it draws a live slider gauge (or switch Key graphic to a rotary Knob or Value / Gauge for just the number), in a vertical or horizontal orientation. (The Pedal has no screen, so you get the sweep but no on-key gauge.)

Keep it in sync with your DAW (optional)

If your DAW automates the same parameter, turn on Feedback (a shared MIDI input, off by default): an incoming CC then moves the dial's value and touch strip — and a Sweep key's value and on-key gauge too — so the hardware follows the automation. (A held Sweep key yields while you sweep it; the dial just shows the latest value, whether from your turn or the incoming CC.) Feedback needs a port your DAW can send to — loopMIDI on Windows, an IAC Driver bus on macOS — and one port can carry both directions; the DAW feedback guide has the routing.

Troubleshooting

• Value jumps instead of sweeping? Lower the dial's Step / tick (or the Sweep key's Sweep time) and set a Range so the sweep stays in a useful window.
• No dial action? The dial action needs a model with dials — the Stream Deck + and + XL are the ones with a touch strip to show the value on. On any other model, use CC Sweep mode, which works on any key.
• Nothing moves? Open the action's settings and read the coloured line under MIDI Port — grey means MIDIRover is sending where you meant, amber that it is sending somewhere else, red that nothing is going out, and it names the port either way. A saved port that has gone missing shows in the dropdown as (not present), and MIDIRover sends nothing rather than pick a different device for you: start loopMIDI (Windows), or re-create the port under the same name and it reconnects on its own within a few seconds. Otherwise check the same port is selected on both sides and the MIDI channel matches.

For every action and setting, see the MIDIRover user manual, or the Neural DSP setup guide.