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Step 5.

 Now every fourth note is tuned from A2 to A4.  Fill in the missing notes between F3 and 

C#4 to get a nine-note mini-temperament.  You must now take a guess at the width of the fourths, 
try it on the mini-temperament, and revise it as necessary to make the fourths fit with the thirds, 
whose width you already know.  A good first guess for fourths is 2.5 cents.  Tune up a fourth from 
F3 to A#3 down a third from A#3 to F#3, up a fourth from F#3 to B3 and stop.  Now tune down a 
fourth from C#4 to G#3, up a third from G#3 to C4, down a fourth from C4 to G3 and stop.  You 
have filled in the six missing notes of the mini-temperament, now you can tell whether your guess 
on the width of the fourths was correct from the width of the G3-B3 third, which is the check 
interval. 
 

Step 6. 

Measure the width of the G3-B3 third and compare it to what it should be.  If it is smaller 

than the other thirds, your fourth guess was also too small, and vice versa.  The size of the error in 
the fourths equal one-quarter the error in the G3-B3 check interval because four fourths were tuned 
to get to the check interval. 
 

Step 7. 

Retune the mini-temperament as in Step 5 with the new correct value for the widths of the 

fourths.  Check it aurally to see that you have five perfectly rising thirds, and four equally good 
fourths.  This result can always be achieved even on the most poorly scaled piano, since we have 
not been asked to make any compromises up to this point. 
 

Step 8.

 Tune outwards from the mini-temperament with major thirds down to A2 and up to A3.  

The thirds tuned downwards are constant width but the thirds tuned upwards may have to be 
calculated if their width varies.  Use straight-line interpolation based on the three known thirds in 
the A3-A4 octave, to get numbers for the missing thirds. (E.g., in Step 4 these three thirds, A3-
C#4, C#4-F4 and F4-A4 were 13.5, 13, and 12.5 cents, respectively.  Straight-line interpolation 
gives values of 13.4, 13.3, and 13.1 for A#3-D4, B3-D#4 and C4-E4, and 12.9, 12.8, and 12.6 for 
D4-F#4, D#4-G4 and E4-G#4, respectively). 
 

Step 9. 

The electronic tuning of the two octaves A2-A4 is now complete.  A very careful aural 

check is advisable at this point.  Pay particular attention to the fourths, which are wider than 
theoretical owing to the effects of inharmonicity.  The fifths are purer than theoretical for the same 
reason, and rarely cause any trouble. 
 

Aural Tuning 
 

The two-octave "A" temperament may be tuned aurally with exactly the same note-tuning 
sequence.  This makes it easy to check an electronic tuning aurally at every step--very helpful in 
avoiding errors.  Aural tuners can study and possibly improve their tuning by using the SOT II to 
measure the width of tuned intervals after setting this two-octave temperament very carefully by 
ear.  
 

Step 1. 

Tune A4 to 440 Hz.  Use F2 as test note, 17th to fork should beat same as 17th to A4.  

Tune A3 from A4 as a 2-4 octave, 1\2 beat wide.  That is, the tenth should beat 1\2 beat per 
second (bps) faster than the third. 
 

Step 2. 

Tune A2 from A3 as a 3-6 octave 1\2 beat wide.  That is, the major sixth should beat 1\2 

bps faster than the minor third.  

 
Step 3. 

Check the double octave, a 1-4 interval to be less than 1 beat wide.  That is, the 17th beat 

should be less than 1 bps faster than the third.  If the double octave is too wide, compromise both 
octaves slightly to get and acceptable double octave. 
 

Step 4. 

Divide the A2-A3 octave into three equal parts by tuning C#3 and F3.  These thirds can be 

tested very accurately with the contiguous thirds test.  This test states that two contiguous thirds 
must have relative beat rates in the ratio of 4 to 5, that is 4 beats of the lower one require the same 
amount of time to complete as 5 beats of the upper one.  This test then does not require knowledge 
of beats per second, only a good sense of rhythm or tempo.  In this case, C#3 and F3 are correctly 

Summary of Contents for SIGHT-O-TUNER II

Page 1: ...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 ...

Page 2: ...N 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 ...

Page 3: ...it 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 J...

Page 4: ... 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...

Page 5: ...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 swit...

Page 6: ...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 4th Partial 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 th...

Page 7: ...ode 2 Play the reference notes one at a time and see how they look on the rotating LEDs 3 Turn the CENTS knob up or down until a cents setting that is a good compromise between the reference notes A cents setting where some of the reference notes rotate slowly sharp and some rotate slowly flat 4 Then tune the note Tuning is more challenging in the last octave because a good compromise may be impos...

Page 8: ...et of A4 at 420Hz Log 420 440 2 1200 80 54 INPUT OUTPUT JACKS There is one input for charging the battery and one output jack on the SOT II The output jack can be set up for a variety of outputs The standard use for the jack when originally manufactured was for an audio input AUDIO IN An electrical audio input jack Signals are fed into this phono jack for silent measurements of pitch or tuning ele...

Page 9: ...the SOT for 30 plus hours and can be recharged hundreds of times To achieve the longest battery life we do recommend that the SOT II be used until the low battery is displayed Li Ion batteries do not benefit from nightly charging but will last longer if used to capacity before recharging BATTERY CHARGING CIRCUIT The Li Ion battery in the SOT II has a large capacity and presently is supplied with a...

Page 10: ...11 7 G 3 9 B 3 9 Eb 11 7 G 9 8 C 5 9 E 2 0 Ab 13 7 C 7 8 F 7 8 The usual practice is to use only the above flats Meantone Temperament A 0 0 Db 27 4 F 10 3 A 24 0 D 3 5 Gb 30 8 Bb 17 1 D 20 5 G 6 8 B 6 8 Eb 20 5 G 17 1 C 10 3 E 3 4 Ab 23 9 C 13 7 F 13 7 The usual sharps and flats are C F G Bb and Eb Marpurg s Temperament 1 A 0 0 C 0 0 F 0 0 A 5 9 D 5 9 F 5 9 B 3 9 D 3 9 G 3 9 C 2 0 E 2 0 G 2 0 Werc...

Page 11: ... 3 9 415 101 3 Formula for calculating cents offset of A4 at 420Hz Log 420 440 2 1200 80 54 APPENDIX C Aural and Visual Tuning The best of both worlds By James W Coleman Sr Owen Jorgenson wrote the definitive work on temperaments and tuning In his book Tuning the Historical Temperaments he traces the natural progress of aural tuning systems from the Pythagorean and Just Intonation systems through ...

Page 12: ...ay notice a slight variation in the sound of the 5ths especially as one approaches the lower area of the scale Sometimes this is merely due to the slipping or instability of the previously tuned upper note of the 5th But with the shorter scaled pianos irregularity of the lower partials may cause the beat frequency to be greater than expected At this point one may make a decision to alter the lower...

Page 13: ...e note of A5 880 Hz At A5 10 cents is the same as G 90 cents since we have 100 cents per half step Now taking the higher reading first we have Ref Hz 880 x 2 raised to 3 7 1200 881 883 Ref Hz 830 61 x 2 to 90 1200 power 874 932 This leaves us with a difference of 6 95 Hz which is the beat frequency of the lowest coincident partials of these two notes With the aid of a scientific calculator one can...

Page 14: ... perfectly as determined by direct interval measurements This leaves every fourth note tuned and the three untuned notes within each major third are then tuned with fourths and thirds again by direct interval measurements Follow the step by step procedure below and be sure to check all intervals aurally as you tune Step 1 Tune A4 to zero cents and A3 from A4 as a 2 4 octave 1 cent wide Refer to Ap...

Page 15: ...3 C 4 C 4 F4 and F4 A4 were 13 5 13 and 12 5 cents respectively Straight line interpolation gives values of 13 4 13 3 and 13 1 for A 3 D4 B3 D 4 and C4 E4 and 12 9 12 8 and 12 6 for D4 F 4 D 4 G4 and E4 G 4 respectively Step 9 The electronic tuning of the two octaves A2 A4 is now complete A very careful aural check is advisable at this point Pay particular attention to the fourths which are wider ...

Page 16: ...th rising thirds all the way with all fourths quite even and acceptable and with all fifths nearly pure APPENDIX F Contiguous Interval Tuning Tests for Electronic Piano Tuners By Dr A E Sanderson Two contiguous musical intervals are intervals that touch each other in other words share the note in the middle Tests that use contiguous intervals are easy to learn and use and tell the tuner explicitly...

Page 17: ... 1 So that aural tuners will know which Accu Tuner settings correspond to the interval tests they have been using 2 So that Accu Tuner users may expand their aural tuning abilities by checking aurally with interval tests and 3 To raise in general the level of knowledge relating to octave tests electronic setting instructions and their use in piano tuning Knowing that there are several types of oct...

Page 18: ... the sostenuto pedal in some cases Play the strike note with a staccato blow Repeat this procedure with the other octave note and the test note When the two beat rates are the same the type of octave which has been tested for will have been tuned The strike note in all cases is the note listed in the electronic setting instructions for that particular type of octave Octave Type Aural Tests Classif...

Page 19: ...lus hours of operation per charge Will recharge in 7 to 8 hours and has a long life expectancy Sight O Tuner II may be battery operated or plugged into an AC line SIZE WEIGHT 7 25 wide 2 high and 4 5 deep Weight 2 0 lbs INPUT OUTPUT JACKS FLTR OUT Filtered audio output at pitch selected by NOTE OCTAVE and CENTS settings OSC OUT Oscillator output for broadcasting an oboe like tone at pitch selected...

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