DrumMonitor

DrumMonitor is a macOS SwiftUI app for MIDI drum timing practice. It helps you train how accurately your pad hits line up with a metronome by combining real-time visual feedback, scoring, and practice modes.

Features

• MIDI source selection and connect/disconnect
• Internal metronome with:
• tempo control (60...180 BPM)
• subdivision support (1/4, 1/8, 1/16)
• ghost mode (N bars on / N bars off)
• beat indicator synchronized to subdivision ticks
• BPM estimate from incoming pad hits when metronome is stopped
• Timing feedback views:
• Phase View (beat-aligned early/late hit display per pad)
• Deviation Meter (instant early/late placement with rolling stats)
• Hit Scatter Timeline (deviation over time)
• Timing Accuracy Score (bucketed scoring + streak)
• Pad Stats (per-pad average and consistency)
• Optional auditory feedback for hits outside a deviation threshold
• Persistent UI settings:
• window size and position
• phase view history mode/settings
• metronome BPM and volume

Tech Stack

• Swift 5
• SwiftUI
• CoreMIDI
• AVFoundation
• Combine

Requirements

• macOS (Xcode project target is configured in DrumMonitor.xcodeproj)
• Xcode with SwiftUI and CoreMIDI support
• A MIDI drum source (hardware or virtual)

Getting Started

1. Clone the repository:

git clone https://github.com/dirkclemens/DrumMonitor.git
cd DrumMonitor

2. Open the project:

open DrumMonitor.xcodeproj

3. Select the DrumMonitor scheme and run on macOS.

Usage

1. In MIDI Source, connect to your drum controller.
2. Start the metronome and set tempo/subdivision.
3. Use Practice Controls to choose:

• focus pad (or all pads)
• normal vs ghost mode
• auditory feedback threshold

4. Watch timing quality across:

• Phase View for immediate early/late alignment
• Deviation Meter for recent timing spread
• Hit Scatter Timeline for drift and trends
• Timing Accuracy Score for measurable progress

Project Structure

• DrumMonitor/DrumMonitorApp.swift: app entry point
• DrumMonitor/MIDIManager.swift: MIDI client, source management, message publish/notifications, shared practice settings
• DrumMonitor/ContentView.swift: main layout + window size/position persistence
• DrumMonitor/MetronomeView.swift: metronome audio, subdivisions, ghost mode, hit BPM, auditory feedback
• DrumMonitor/OscilloscopeView.swift: beat-aligned phase view
• DrumMonitor/DeviationMeterView.swift: deviation meter
• DrumMonitor/HitScatterTimelineView.swift: scatter timeline
• DrumMonitor/TimingAccuracyScoreView.swift: score + streak
• DrumMonitor/PadStatsView.swift: per-pad stats
• DrumMonitor/PracticeControlView.swift: training mode controls

Notes

• Timing visuals use incoming MIDI Note On events with velocity > 0.
• Most views rely on metronome tick notifications for alignment; start the metronome for best results.
• Some experimental/legacy views still exist in the codebase but are not currently part of the main screen.