Introduction

Hemiola is a multi-platform music app that lets you: play a piano keyboard, connect MIDI instruments, upload your own SoundFont files, create analog synth sounds, add audio effects, configure external MIDI devices, and use it as a MIDI router — with the same experience across all platforms.

Hemiola is free on mobile. The Free version allows up to 3 presets per section. A one-time Pro upgrade (iOS/Android) removes that limit. Cloud subscriptions unlock additional features and supersede the one-time purchase for the duration of the subscription — see the Cloud Account section for details.

Cloud features include automatic backup, preset sync across devices, a Community Library for browsing and publishing shared presets, bookmark syncing, push notifications, and a public profile.

Presets & Scenes

A preset icon (library/music) is always visible in the top bar. It is grey and disabled in sections that have no preset support. It turns accent-coloured when presets are available and the current state is saved; it turns orange when there are unsaved changes (dirty state).

• Preset dialog (clean): tap a preset to apply it immediately. Tap the edit icon to rename, or the delete icon to remove a user preset. The default "—" preset cannot be modified or deleted.
• Preset dialog (dirty): tap a user preset to overwrite it with current values, or use the Add New button to save as a new named preset. A Discard option resets to the last saved state.
• Sections with preset support: Piano Keyboard (scale, scroll position, pressure, haptic), Sound (analog synth + effects), Configuration Tool device pages, and MIDI Mapper (full mapping list with active/inactive state).

App Bar

The app bar at the top contains persistent actions available on every screen.

• Hemiola logo → Home screen; also acts as a Back button when inside a sub-screen.
• Bell icon (Push Notifications) → shown for both signed-in users and guests; displays a red badge with the count of unread notifications. Tap to open the notifications panel directly below the icon. See the Push Notifications section for details.
• Community Library icon (cloud) → opens the shared preset library where you can browse, apply, import, and bookmark presets published by the community. Appears grey with a bar when the app is offline.
• Scenes icon → save and restore a full snapshot of all Sound Generator and MIDI settings in one step
• Preset icon (library/music) → always visible; grey when the current section has no preset support, accent-coloured when clean, orange when there are unsaved changes
• Battery icon → shown only while Config Tool is the active tab, for compatible devices

Bottom Tab Bar

The bottom bar gives quick access to the four main sections.

• Piano icon → Piano Keyboard
• Link icon (Config Tool) → accent-coloured when a supported device is connected; long-tap to activate plugin Developer/Sandbox mode
• MIDI icon → MIDI Device Manager; accent when a device is connected; long-tap opens the MIDI Console directly
• Equalizer icon (Sound Generator) → accent when the generator is playing; long-tap to toggle on/off

Knobs

• Drag up or right to increase the value; drag down or left to decrease
• Tap the arc to jump directly to that position
• Double-tap the knob to reset to the default value
• Long-press the value label to open a modal editor for exact numeric entry.
• Long-press the knob body (hold without moving) to enter Fine mode: the drag sensitivity is reduced 10×, allowing very precise adjustments. A red border appears on the knob body while Fine mode is active. Fine mode deactivates automatically when you release.

App Updates

• Store Updates (App Store / Play Store): new features and bug fixes
• In-app Updates: embedded SoundFont files, new configuration tool device pages, and Help system updates
• When an in-app update installs a new supported device plugin, the device catalog is refreshed immediately without restarting the app.