Relative major and minor
C major and A natural minor share a key signature and pitch collection. Their tonal centers differ, so the same set of note names does not by itself determine which key a passage establishes.
In this guide: SESSION™ Key. Apple silicon · macOS 14.4+ · Up to 3 Macs. Price and requirements.
Published by Capiscana, Inc., maker of SESSION™ products. About these comparisons.
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Hear which note resolves
Listen to phrase endings, the bass and harmonic motion. A phrase that settles on A can establish a different tonal context from one that resolves to C, even when both use the white notes of a keyboard.
Do not reduce minor to one scale
Minor-key music often changes scale degrees, including a raised leading tone. Those alterations can help clarify harmonic function; a key signature alone does not describe every note used.
Diagnose a disagreement
If two readings form a relative pair, check the section and its cadences. The relationship explains a common ambiguity, but it does not prove that either detector is correct or that software errors are impossible.
Using SESSION™ Key
Read system audio, use the microphone, or drop an audio or MIDI file on the menu bar. Live analysis follows the passage playing; a file gives the analyzer a different span of material.
The outline marks a locked reading; green and amber communicate confidence separately. A locked reading can still be uncertain. Listen, check the musical context, and use the half-time or double-time control when the pulse needs it.
Put the result to work
Key and tempo in Pro Tools · Use Key with Ableton Live · Check a reading you do not believe · Compare analysis tools
Sources and scope
Product documentation reviewed October 17, 2026. These are comparisons of published capabilities, not independent performance tests. Prices and availability can change.
The musical explanations are editorial guidance; the product source supports the descriptions of Key. Check a disputed tonal label against the actual music.