Same pitch. Different meaning.
In F# major, the seventh degree is E#. It sounds like F in equal temperament, but its letter tells you its job in the scale.
A LITTLE THEORY. A LOT OF POSSIBILITY.
See it. Hear it.
Understand it.
Follow the notes from a scale to a chord.
Make the connection with your ears.
YOUR EXPLORATION
One idea. Five ways in.
Hear C majorReady when you are · synthesized sine tones
A small formula. Every pitch.
f = 440 × 2(m − 69) / 12
12-tone equal temperament. A4 is 440 Hz; C4 is approximately 261.625565 Hz. Here, m is the MIDI note number.
Let your ears take the lead.
Listen to a hidden interval or chord. Replay the same question, make your guess, then see the notes behind the sound.
What this lab supports +
A deliberately focused toolkit
Five scales: major, natural minor, harmonic minor, Dorian and Mixolydian. Eleven chord types: major, minor, diminished, augmented, sus2, sus4, maj7, m7, dominant 7, m7b5 and dim7. Progressions accept 1–16 space-separated chord symbols.
Notes accept #, b, ## (or x), bb, ♯ and ♭. Triple accidentals, slash chords, extensions and unsupported suffixes return a clear error. Reverse lookup matches 3 or 4 distinct pitch classes against these eleven chord types; it does not determine a unique harmonic meaning.
Pitch, spelling and octaves
Octaves use scientific pitch notation: C4 is middle C; an octave changes at C. Explicit interval notes may use octaves 0–8 within sounding C0–B8. Enter octaves on both notes, or neither. Without octaves, intervals ascend within the next letter cycle.
Intervals support simple and compound distances through a 15th, with perfect, major, minor, singly augmented or diminished qualities. Chromatically reversed letter order and doubly altered interval qualities are rejected. The global playback octave sets scale, chord, progression and exercise roots; written interval octaves take precedence.
Sound and your workspace
Audio begins only after a play or exercise click. Sine tones are generated in your browser, with short fades and conservative volume. A new play, mode change, stop or hidden tab clears prior voices. No microphone, recordings, samples or song scores.
A valid workspace is saved locally in this browser. Save project downloads JSON; Restore validates and restores it. Theory card downloads a printable HTML explanation of the active result. Ear-training questions and scores are session-only. Physical-device playback has not been tested.
Independent tools, connected learning. Further resources: musictheory.net calculators ↗Theory exercises ↗OneMotion Chord Player ↗SA Education resource ↗