Pro Metronome & Tuner

Pro Metronome — A Metronome Built by Engineers, for Musicians

This isn't another ticking app. We rebuilt the metronome core from the ground up using a native C++ audio rendering pipeline on Core Audio, computing every beat in the audio render thread at sub-sample precision. There is no Timer, no main-thread scheduling, and no drift — practice for an hour or for ten, every click lands exactly where it should.

— Precision — • Sample-accurate timing: beat intervals are computed in double-precision audio samples (samplesPerBeat = (60/BPM) × SampleRate), accumulating zero drift over time • Lock-free atomic state: changes to BPM, time signature, and subdivisions take effect instantly without interrupting the audio stream • BPM 40–240 with ±1/±5 nudge, long-press continuous adjust, and TAP tempo input

— Comprehensive Subdivisions — This is where we put the work in. Every base note value ships with a full library of rhythmic patterns: • Quarter note: 14 patterns (duplets, triplets, triplets with rests in any position, sixteenths, dotted 8th+16th, syncopation, etc.) • Half note: 16 patterns • Eighth note: 8 patterns • Sixteenth note: 4 patterns • Whole / longer: 6 patterns Each pattern is encoded as a bitmask of active slices and paired with a visual notation icon — so you can drill not just standard triplets and sixteenths but real syncopation, dotted figures, and rest-driven groove patterns.

— Studio-grade Tuner — A built-in chromatic tuner with the response time of a hardware unit: • YIN autocorrelation pitch detection: the industry-standard low-latency, high-robustness algorithm with proper octave handling • Biquad low-pass pre-filtering to reject high-frequency room noise and harmonic confusion • Adaptive noise gate — no false triggers in noisy rooms • Cents smoothing (factor 0.7) with 1.5s hold for a rock-steady readout • Automatic octave detection from C0–B8 — works for guitar, bass, piano, violin, brass, woodwinds, voice • Shares the audio session with the metronome, switches in/out without conflict

— Features Real Players Need — • Left / Center / Right channel output: routing the click to one ear of your headphones lets the other ear stay open for the band — ideal for in-ear monitoring • Background playback: lock the screen, switch to a backing-track app, walk away with AirPods — the click keeps going • Lock-screen & remote controls: start/stop from Control Center or in-line headphone buttons • 4 preset slots: store BPM, time signature, rhythm pattern, accent, and sound for every song in your set, switch on stage in one tap • 6 click sounds: Classic, Woodblock, Cowbell, Hi-Hat, Rim Shot, Electronic — every sound is synthesized in DSP for zero-latency response, not sampled playback • Per-beat accent control: strong / medium / weak (red / orange / blue, distinct frequencies) — perfect for 3/4, 5/8, 7/8 and other compound meters • Optional bar counter: don't lose count during long loop drills

— Personalization — • Dark / Light / System appearance • Keep-screen-on toggle for long practice sessions • English and Chinese localization

Built for everyone who treats practice time as quality time.