TuneLab Only - Article 3

[Jim Coleman, Sr.]

Hi:

Here is the article I promised TuneLab users for the Acrosonic spinets.

Acrosonic Tuning Curve using partials 6,4,1 with TuneLab

1. Double click on Tlab Icon
2. Tune A4 fundamental to a stopped display pattern. Hit Insert, Enter, ESC
3. Hit PgUp to A5 but Play A4 and stop display with cents keys increasing 
    ith u,i,o (=10,1, .1 resp.) or decrease with j,k,l (=-10.-1,-.1). After
    the display is stopped, add one more cent with the "i" key for more 
    stretch.
4. Tune A5 to this setting playing A5 and stopping the display pattern. Hit
    Ins, Enter key, click on A4 and drag to A5 in drop down window, click 
    Set at left, then ENTER, ESC key, "z" key.
5. Hit PgDn twice to A3 (use Function key F4 if necessary to get partial 4)
6. Play A4, stop display with cents keys as above. You may decrease this 
    value by 1 cent if you like additional stretch as I do. Hit Insert Key,
    then Enter key to store this value for A3 (4th partial), then Enter,
    ESC, and "z". Now we can store A4 (partial 4)
7. Hit PgUp to A4, change to 4th partial using the F4 function key.
8. Play A4, use cents keys u,i,o or j,k,l to stop display. Hit INS key & 
    Enter.  Click on A3 and drag to A4 (4th partial) and click on SET. At 
    the confirming window, the cursor blinks on the A3, hit Backspace and 
    type in G3 (the lowest plain string on an Acrosonic spinet; for a 
    Wurlitzer the lowest is usually G#.) Hit Enter key, hit ESC, "z" key. 
    See Graph with F1 key, then ESC.
9. Tune all notes from A4 down to G3. I like to lower G# and G3 a little 
    more because they have higher inharmonicity than their neighbors. When
    at G#3, hit the "L" key 5 times to make the note 1/2 cent lower. Then
    Hold down Ctrl key and touch letter "e" to combine this .5 cent offset 
    with the stretch tuning value. Do a similar thing for the G3, except 
    hit the "k" once to lower G3 by 1.0 cents. Use Ctrl-e to store that 
    change.
10  Left arrow to F#3, change to partial 6 using the F4 key.
11  Play F#4, (computer will be listening to its 3rd partial so we can 
     tune the 6th partial of F#3 to it), stop the display with the cents 
     keys.
12  Tune F#3 to this setting (this makes a 6-3 tpe octave), hit INS, Enter
     and ESC, then "z" key to zero the offset.
13  Hit "a","2" to get A2 (use F4 key to get to partial 6 if necessary. Play
     A3 and, with the cents keys, stop the display. This helps to match the
     A2 (6th partial) with the A3 (3rd partial).
14  Tune A2 to this setting making a perfect 6-3 type octave where the 6th 
     partial of the lower note matches the 3rd partial of the upper note.
15  Hit INS, Enter, click A2 and drag to F#3, then click on SET in the 
     other window. Hit Enter, ESC, "z" key to zero the offset.
16  Tune all notes from A2 to F#3 and also from A4 thru A5. This will give
     you about as good a 2 octave temperament as can be had with this scale.

With this system, there may be a tiny bit of tweaking one can do below the 
     F-F temperament area such as raising the C#3 and D3 by about 1 cent 
     each. This will make their 5ths a little busier. but it will help the
     M3rds, octaves and double octaves fit very well.

This approach using 4th and 6th partials is far better than using second 
     partials to tune by because it automatically stretches out the A-A 
     temperament very well and by making the shift to using 6th partials 
     beginning with the wound strings, it leaves very little additional 
     tweaking to be done. Just remember that when a scaling break is as 
     wild as this one is (I first wrote about this in 1961) it is 
     impossible to have everything balance out perfectly. When I worked 
     for this company, I offered to rescale this piano, but was told that 
     the piano then commanded 40% of the market and they weren't about to
     change anything on it. Well, what do you know? They now have 100% of
     the spinet market. I guess I wasn't so smart after all.

In the next article, I will take up the curve programming for the rest of
     the octaves and then do the same thing for RCT and SAT I,II and III
     as I have done for TuneLab.

Jim Coleman, Sr.

PS Give me some feedback privately if you like or don't like this cookbook 
   style of instructions. JWC