
4
MEASURING THE F4 STRETCH NUMBER
1)
Set the Sight-O-Tuner to F5, zero cents in the TUNE mode (stretch button not backlit). Play one
string of F4 and use the COARSE cents knob to stop the rotation of the LEDs.
2)
Turn the OCTAVE knob to step up one octave to F6, and play F4 again, and use the FINE cents
knob to stop the rotation of the LEDs. The fine cents knob now displays the F4 stretch number,
which is the difference in cents between the second and fourth partials of F4. Please jot down
the stretch number for use in step 5 or make a mental note.
3)
Now set the SOT to note A, octave 4, and both COARSE and FINE cents to zero. Tune the note
A4 on the piano or if not tuning to A 440 Hz, offset the cents accordingly.
4)
Step the SOT up one octave to A 5, play the note A4 on the piano and use the COARSE and
FINE cents knob to stop the rotation of the LED’s.
5)
Now press STRETCH button, the STRETCH button will be backlit red, now turn the FINE cents
knob to the stretch number you measured in step 2. Now the SOT II will automatically set the
CENTS for the selected stretch number. No need to turn either of the CENTS knobs, just set the
NOTE and OCTAVE switches to the desired note between C3 and F6. The COARSE knob has
no effect on the setting of the stretch number, if the stretch number is 8.0 set the FINE cents
knob to -1.0, stretch number of 9.0 set the FINE cents knob to -2.0.
6)
Now the microprocessor will automatically set the cents for the correct deviation according to
the old stretch calculator slide card.
You are all set to start tuning the note C3. To start at any other note between C3 and F6, just
proceed to that note with the NOTE and OCTAVE switches.
SOT II with the STRETCH button lit.