Boss BR-80 Owner's Manual page 119

If your instrument matches the displayed pitch
If your instrument is sharp
4.
Repeat steps 1–3 to tune each string
of your instrument .
MEMO
If you're tuning a guitar that has a
whammy bar, tuning one string might
cause the other strings to drift out of
tune. Start by tuning each string to the
approximate pitch so that the correct
note name is displayed, and then retune
each string successively as many times
as needed.
Specifying the reference pitch
When tuning an instrument, the reference
pitch is conventionally given as the
frequency of the A4 note (middle A on a
piano keyboard).
You can adjust the tuner's reference pitch in
the range of 435–445 Hz.
In the TUNER screen, you can use the dial to
set the reference pitch.
With the factory settings, this is set to 440
Hz.
MEMO
The reference pitch setting is saved
within the BR-80.
Tuning Your Instrument
119