How Practice Works
FrostNote provides 28 pitch cards. It first plays a reference tone generated by the browser, then continuously estimates fundamental frequency from the microphone. You complete a card by entering roughly ±25 cents of the target pitch and staying there long enough; leaving the tolerance zone breaks or reduces the continuous hold.
On first use, you can choose a comfortable vocal range and adjust the octave so exercises do not stay in an unsuitable range. The score combines hit rate, stability, and completion time to give feedback on that practice session, not to grade your voice.
What Stays in the Browser
Practice playback is kept only in an in-memory Blob and is released when you switch cards, restart, or refresh the page. Public leaderboards show only score names authorized for publication or anonymous records.
Why Detection Sometimes Jumps an Octave
The human voice contains a fundamental frequency and many harmonics. Ambient noise, excessive reverberation, breathiness, humming style, and device noise reduction can make a harmonic stand out more than the fundamental, causing the algorithm to briefly detect twice or half the actual frequency. Moving closer to the microphone without causing plosives and sustaining a stable vowel is usually more effective than simply getting louder.