Setting up a Reference Tone: When you power up the TU300, it is set to 440Hz.
1) Press the STREAM/CENT and the MODE button simultaneously.
2) Increase the reference tone in 1-Hz steps by pressing the MODE button.
3) Decrease the reference tone by pressing the STREAM/CENT button.
The Display will show 8/9/0/1/2/3/4/5/6/7 to indicate the reference tone from 438 to 447Hz.