The Milwaukee servoelectric guitar design uses three identical 0.017 nickel plated steel strings each tunable over the same octave. The use of identical strings with identical tuning ranges simplifies the design considerably but does not allow all three-note chords to be played in the normal and inverted form. For this purpose, one string should be offset to an octave range of above a range of a lower string.
The scale length for the guitar (from nut to bridge) is 19 inches, substantially less than the standard guitar length of 25.5 inches. The strings may be tuned between (d) 146.8 Hz and (c#) 277.2 Hz. From the calculator, below this requires changing the tension on the string from 5.1 pounds to 18.3 pounds. The equation for tension, implimented by the calculator is:
Tension=(Unit_Weight*(2*Scale_Length*Frequency)^2)/386.4
where
Unit_Weight is in pounds weight per linear inch
Scale_length is in inches
Tension is in pounds force
Note that a doubling of the frequency requires a substantially greater proportion (four times) increase in tension. The strings at their lower range are tuned somewhat lower than normally used in an acoustic guitar but because mechanical coupling of the vibrations to the guitar body is not required for an electric guitar, this does not seem to be a problem. By decreasing the neck length and down-tuning the strings, a relatively small 13 pound excursion is maintained which can be readily handled by the motors when compensated with the compensator wheels.
