The macOS engine that thinks like a DJ. Cella reads BPM, key, LUFS and vocals from every track — then beat-aligns the crossfade so nothing ever lands on top of a lyric.
Built for macOS Sonoma · Apple Silicon
A Swift actor pipeline analyses, orders and blends your library — harmonic-aware, vocal-safe, quantized to the bar.
A Swift actor runs concurrent analysis on every file — tempo, key, integrated loudness, structure, and vocal activity — downsampled for speed without losing the detail the engine needs.
A dot-matrix display that breathes with the mix — energy, mood and transition state in one glance.
MixEngine scores every pair on five weighted axes, then solves the set with nearest-insertion TSP and a 2-opt refinement.
Dual AVAudioEngine players trigger on optimal bar boundaries, glide tempo with a smoothstep ramp, and duck vocals so no lyric ever lands on top of another.
Three tabs. Feeds for reading, Cella for listening, Config for the library. Fullscreen, keyboard-first, native on Apple Silicon.
Read while you listen. A minimal EPUB library with progress tracking, cover art, a mini now-playing bar, and a gentle water reminder timer.
A rhythm found me before I found it. It was warm, and it was patient.
The needle dropped and the room, for a moment, agreed to listen.
Somewhere between the verse and the chorus, an hour disappeared.
Flat, plus curves tuned for Bose, Sony, Apple, Sennheiser, Beats, JBL and AKG — routed through spatial delay, hall reverb and a peak limiter.
Point at any folder. Files named Artist — Title are parsed automatically.