The TU-3 Tuner provides an alternate Mode to tune with that provides some extra visual pin-pointing, beyond what Regular Mode offers, to help with the Tuning process.
To turn the Accu-Pitch function on, or off:
1. While holding down the STREAM/CENT button, turn on the power (insert a plug into the INPUT jack).
2. Press the STREAM/CENT button again to toggle the Accu-Pitch Sign function on either or off.
Difference between the two Modes:
Regular Mode: single pitch light in the middle of the curved LED display only.
Accu-Pitch Mode: in addition to this light you'll also see two lights coming from the left and right that come together to the middle when you reached the pitch you're trying to tune to.