Always In Key
The scale-locking engine snaps every note into the active scale, so a wrong note is simply not on the table.
Real-Time Key & Scale Detection • Play-In-Scale Instrument
PlayScaler
PlayScaler listens to any music, figures out its key and scale in real time, and lets you play along on any instrument without ever hitting a wrong note.
Real-TimeLive key & scale detection
26Scale families
300+Key / scale combinations
12Keys covered
INSIDE PLAYSCALER
The Whole App, at a Glance
Real-time key detection, a circle-of-fifths key wheel, confidence and BPM, a live spectrum, color-coded detected chords, instrument categories, and a scale-locked keyboard — all in one native macOS window.
CORE PLAY-IN-SCALE ENGINE
Never Play a Wrong Note
Every note you play is intelligently mapped to the detected — or chosen — scale, so beginners and pros always sound in key.
Any Input, One Engine
The on-screen piano, your computer keyboard, and a hardware MIDI keyboard all run through the same scale-locking engine.
Toggle On Demand
Keep scale-locking on for guaranteed-in-key playing, or switch it off any time to play completely freely.
REAL-TIME MUSIC ANALYSIS
The Key of Any Track,
Detected as It Plays
Key & Scale Detection
- Automatic key and scale detection from live audio
- 26 scale families across all 12 keys (300+ combinations)
- From major and minor to modes and exotic scales
Chords & Tempo
- Live chord detection recognizes the progression as it happens
- BPM (tempo) detection keeps you in time
- Confidence meter shows how sure the detector is
You Stay in Control
- Manual override to lock any key and scale yourself
- Stop, reset, and re-analyze on demand
- Searchable key & scale picker for quick selection
FLEXIBLE LISTENING SOURCES
Detect the Key of Anything
Point PlayScaler at a live instrument, your whole Mac, or a single app — whatever you want to jam along with.
Microphone / Line-In
Detect the key of a live instrument or the audio in the room.
System Audio
Detect the key of anything playing on your Mac, from any source.
Per-App Capture
Point it at a specific app — like a streaming or music player.
Interface & Device Select
Choose your audio interface and input device for a clean signal.
PLAY IT YOUR WAY
Turn Any Keyboard Into a Scale-Locked Instrument
On-Screen Piano
Click to play with live highlighting of active and in-scale notes right on the keys.
Computer Keyboard
Perform on the QWERTY home row with Z/X octave shifting and an on-screen range indicator.
Hardware MIDI Keyboard
Auto-detects MIDI keyboards plugged in at any time — just play.
Color-Coded Chord Keys
Detected chords are assigned colors and mapped to keys, so one press triggers a full chord.
BUILT-IN INSTRUMENTS & SOUND
A Whole Instrument, No DAW Required
The standalone app ships with its own sounds, so you can open it and start playing immediately.
Bundled Sound Library
A dedicated grand piano plus a full General MIDI sound set — no external plugins needed.
Instrument Categories
Piano, Guitar, Synth, Strings, and Bass right at your fingertips.
Play Immediately
No DAW, no setup — the standalone app includes its own instrument so you can jam on day one.
STUDIO EFFECTS & VISUAL FEEDBACK
Shape the Sound,
See the Music
Studio Effects & Output
- Reverb with mix, room size, and damping for instant depth
- Delay / echo with time, feedback, and mix
- Master volume fader right in the main window
- Output device selection for headphone or monitor preview
Visual Feedback & Control
- Circle-of-fifths key wheel of the active scale
- Live spectrum display of the incoming audio
- Detected-chord panel with color-matched chords
- Clean, branded, native macOS interface
JAM IN KEY WITH ANY SONG
Sound like a pro on day one — no wrong notes.
PlayScaler turns any track into a scale-locked jam session: detect the key in real time, then play along on any instrument and stay in key the whole way through.
Jam in key with any song — instantly.
The key of any track, detected in real time.
Sound like a pro on day one — no wrong notes.
Turn your computer keyboard into a scale-locked instrument.