The.ensemble
Tune the chord, not just the note.
A quartet reads a new piece. Bar twelve, a D major chord, and it beats. The viola
says the cello is low, the cello says the F♯ is high, the second violin is sure it
is the viola, and the first violin moves anyway. Twenty minutes later the chord
still beats and nobody knows who moved.
Leave Spectrum listening on the stand through the rehearsal. It hears the
four of you at once and puts beside every note how far it is from the tuning system
you agreed on. Under the picture it names the chord, and shows how far each note is
from the pure interval over the root that was actually played.
The F♯ a tuner calls twelve cents flat is four cents high against the cello's D.
That is the note that moves, by four cents, and the chord stops beating. The
argument takes as long as reading two numbers.
The map is for practising on your own, one note at a time. Spectrum is for playing
together, and records nothing. On the free plan it listens two minutes a day;
after the €4.99, for as long as the rehearsal lasts.