Unison
The same note played twice, or by two instruments at once. It is the reference point: the only interval with no tension, and recognizing it confirms the ear is calibrated before you begin.
Listen
See
C → C
Where you have heard it
Afinação de orquestra the oboe’s A
Coro em uníssono all voices together
Nota repetida same pitch, new attack
What it gets confused with
Frequently asked
How many semitones is a unison?
Zero. Both notes are the same pitch — the interval exists as a reference, not as a distance.
Is a unison the same as an octave?
No. An octave spans twelve semitones. They are confused because both are perfectly consonant, but the octave has an audible gap between the two notes.
Why train the unison at all?
It calibrates the ear before you start: it is the only interval with no tension, so it sets the baseline you compare everything else against.
There is an exercise track dedicated to recognising this by ear.
Train this