Inventronics SIGHT-O-TUNER II Operating Manual
SIGHT-O-TUNER II
OPERATING MANUAL
INVENTRONICS, INC.
130 MIDDLESEX RD, Suite 14
TYNGSBORO, MA 01879-2725
www.Accu-Tuner.com
Inventronics@aol.com
1-800-FAST-440
Outside USA/Canada CALL 978-649-9040
WRITTEN BY:
PAUL L. SANDERSON
BRIAN DAY
THIS MANUAL IS COPYRIGHTED. ALL RIGHTS ARE RESERVED. THIS DOCUMENT MAY NOT, IN
WHOLE OR PART, BE COPIED, PHOTOCOPIED, REPRODUCED OR TRANSLATED WITHOUT PRIOR
CONSENT IN WRITING FROM INVENTRONICS, INC.
©2012 INVENTRONICS, INC.
TYNGSBORO, MA 01879
INTRODUCTION .............................................................................. 2
GETTING STARTED ......................................................................... 3
LOW BATTERY INDICATOR .............................................................. 3
THE TWO MODES OF OPERATION .................................................... 3
THE TUNE MODE............................................................................ 3
STRETCH TUNING .............................................................................. 3
MEASURING THE F4 STRETCH NUMBER ........................................... 4
STRETCH TUNING PARTIALS ................................................................. 5
STRETCH TUNING FROM C3 TO F6........................................................ 5
UNISON TUNING.................................................................................5
TUNING BEYOND C3 TO F6.............................................................. 6
DIRECT TUNING THE HIGH TREBLE................................................... 6
DIRECT TUNING THE BASS.............................................................. 6
CENTS OFFSET FOR HZ AT A4 ...............................................................7
INPUT-OUTPUT JACKS .................................................................... 7
BATTERY CARE............................................................................... 8
LITHIUM ION.................................................................................. 8
BATTERY CHARGING CIRCUIT ......................................................... 8
ONE YEAR WARRANTY.................................................................... 8
APPENDIX A ................................................................................... 9
CONCISE STEP-BY-STEP TABLES OF STANDARD ROUTINES .............................9
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APPENDIX B.................................................................................... 9
CENTS TABLES FOR NON-EQUAL TEMPERAMENTS ........................................9
CENTS OFFSET FOR HZ AT A4 ............................................................. 10
APPENDIX C ................................................................................. 10
AURAL AND VISUAL TUNING................................................................10
APPENDIX D ................................................................................. 11
WHAT ARE PARTIALS AND BEATS? ........................................................ 11
APPENDIX E.................................................................................. 12
THE TWO-OCTAVE "A" TEMPERAMENT .................................................. 12
APPENDIX F.................................................................................. 15
CONTIGUOUS-INTERVAL TUNING TESTS FOR ELECTRONIC PIANO TUNERS.......... 15
APPENDIX G ................................................................................. 16
OCTAVE TUNING .............................................................................. 16
SIGHT-O-TUNER II SPECIFICATIONS................................................ 17
INPUT/OUTPUT JACKS ..................................................................18
SIGHT- O-TUNER® II
INSTRUCTION MANUAL
INTRODUCTION
The Musicalibrator (later renamed the Sight-O-Tuner (SOT)) was originally invented and designed by
Dr. Albert E Sanderson in the early seventies as a prototype to tune pianos. The invention led to the
application and granting of eight patents on circuit design and the method of measuring
inharmonicity to create a tuning that took inharmonicity into account. The patent rights were later
licensed to Tuners Supply to produce the Sight-O-Tuner. After a few years went by, there was an
attempt by Tuners Supply to change overnight the reimbursement terms of the contract that led to
a lawsuit. Those problems with the contract prompted Al Sanderson to redesign and start
producing the Sanderson Accu-Tuner® in his basement. By producing the product himself, Dr.
Sanderson had control over the quality and quantity of the units produced. Initially Inventronics was
repairing the Sight-O-Tuners to help out piano technicians in an attempt to keep quality of the SOT
up to Dr. Sanderson’s standards.
Jumping forward thirty years, recently the last person repairing the Sight-O-Tuners passed away,
and we received quite a few phone calls asking who would repair the Sight-O-Tuners. This got the
ball rolling to create a solution. Quite a few of the components in the SOT are no longer available
and repairing the original circuit design was not an option. So one of Inventronics employees, Brian
Day, started working on the idea of replacing the entire electronics and using some of the circuit
designs Inventronics uses in the production of the Accu-Tuners. This is the solution Inventronics has
come up with to keep the SOT owners in business until they are ready to step up to the Sanderson
Accu-Tuner.
Tuning with the new electronics in the Sight-O-Tuner II (SOT II) is very similar to the previous SOT
with two new features:
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1) The SOT II can automatically set the cents for a Stretch Tuning.
2) Coarse cent dial can be set up to jump to the nearest five cent increment, for more
accuracy.
GETTING STARTED
When the SOT II is turned on, the SOT II starts in the self-calibrating state for two seconds, two
LEDs will be lit, generally at three and nine o’clock, and then automatically switches over ready to
tune.
The SOT II will be fully charged when received. The Lithium Ion (Li-ion) battery will function for
thirty or more hours before charging is required. This battery is tolerant of deep discharge, and the
SOT II will turn itself off at a safe low-battery voltage, shortly after the Lo Battery LED is lit.
LOW BATTERY INDICATOR
The SOT II indicates the low battery similar to the original SOT, the LED between six and nine
o’clock will remain lit. Shortly after the LO Batt LED is lit, the SOT II will turn itself off to before a
low battery condition can create unstable results.
THE TWO MODES OF OPERATION
The Sight-O-Tuner II has two basic modes of operation:
1) The TUNE mode.
2) The Stretch Mode
1) When the SOT is first turned on, calibration signal will display for two seconds, and then it
enters the TUNE mode.
2) There is a new button between the COARSE and FINE labels on the face of the SOT. Once you
have measured the stretch number, press the STRETCH button, the partial and cents deviation
for the stretch tuning will automatically be set internally.
THE TUNE MODE
Immediately after exiting from the CALIBRATION mode, whatever the combination of the NOTE,
OCTAVE, FINE and COARSE cents knobs are set to is the pitch that the SOT will be tuning. This is
essentially what you see is what you get, as long as the STRETCH button is NOT LIT.
STRETCH TUNING
The previous Stretch Calculator slide rule is replaced with the ability of the new microprocessor to
set the partial and cents automatically for you. This improvement will make the tuning of a piano
quicker and being able to re-check the tuning almost instantaneous. In this mode, the Sight-O-Tuner
II creates a 41 note tuning that is derived from the measurement of the stretch number from F4 on
the piano being tuned. Every time the note or octave is changed, the computer references the
stretch tuning from the memory and sets the partial and cents deviation correctly for that note.
The new SOT has the stretch tuning curves built in for stretch numbers from 2.0 to 9.0, which
works out to fifteen different stretch curves are built in for automatic setting of the cents knob.
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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.
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STRETCH TUNING PARTIALS
When the SOT II creates a stretch tuning, the program creates the tuning and it is automatically set
the SOT II to the correct partial in the following manner. This is illustrated in more detail in the
following tables:
OCTAVE PARTIAL KEYBOARD PITCH OF PARTIAL
Octave 3 Fourth Partial C3 C5
Octave 4 Fourth Partial F4 F6
Octave 4 Second Partial F#4 F#5
Octave 5 Second Partial F5 F6
Octave 5 Second Partial F#5 F#5
Octave 6 First Partial F6 F6
Just to reiterate, C3 to F4 fourth partial, F#4 to F5 second partial, F#5 to F6 fundamental partial as
shown in the table below.
Piano
Note
C3 C5 F#4 F#5 F#5 F#5
C#3 C#5 G4 G5 G5 G5
D3 D5 G#4 G#5 G#5 G#5
D#3 D#5 A4 A5 A5 A5
E3 E5 A#4 A#5 A#5 A#5
F3 F5 B4 B5 B5 B5
F#3 F#5 C5 C6 C6 C6
G3 G5 C#5 C#6 C#6 C#6
G#3 G#5 D5 D6 D6 D6
A3 A5 E5 E6 E6 E6
A#3 A#5 F5 F6 F6 F6
B3 B5
C4 C6 2nd Partial 1st Partial
C#4 C#6 (Fundamental)
D4 D6
D#4 D#6
E4 E6
F4 F6
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STRETCH Tuning from C3 to F6
After the stretch tuning has been selected, (stretch button backlit) tuning can start on any note
between C3 and F6. When ready to tune the next note, turn the NOTE and or OCTAVE knobs. For
every semitone the SOT will automatically update the partial and cents deviation for the next note,
continue this way for the notes C3 to F6. Just to verify: the SOT should be set to the note on the
piano you are tuning and the SOT II automatically selects the partial and cents deviation.
Unison Tuning
Unisons may be tuned aurally along with a stretch tuning of the center string, or each string may be
tuned individually to the SOT II and the unisons checked aurally later on. The SOT II will do an
excellent job of tuning unisons when the strings of a given note are well matched. (They are on
SOT
Automatically
listening to
th
Partial
Piano
Note
SOT
Automatically
listening to
Piano
Note
Automatically
listening to
SOT
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