Peterson AutoStrobe 490ST - Manual (Page 25)

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We are assuming that we have chosen a valid name for our file and have, consequently, followed the “NO” path from the
“Name already exists?” decision box on the flowchart. Thus, we have now entered the “Edit Notes” phase of our stretch file
creation. From this one screen, we can now define the note offsets for 96 notes (8 full octaves). Note that this screen shows
you which stretch file you are editing as well as which octave and which note within that octave you are editing. Also note
that a “KEY=C” indication is shown on the top line.
NOTE: Regardless of what key signature was current before entering the edit process for either temperaments or stretches,
the key always reverts to “C” for the purposes of defining note offsets. Once the editing process is complete and you return
to the RUN screen, you may enter any of the alternate keys with the usual results. However, if you applied an offset of
1.1 cents to D-octave 2, for example, this offset will always apply to “Concert D” regardless of the new KEY you have
selected.
The “cents” indication on the second line of this screen is always indicates the individual offset currently selected for the
displayed note in the displayed octave. Had we been editing a previously defined stretch file, this first screen may have
shown a non-zero number here. Because we are creating a new stretch file this and all the remaining 95 notes will be
initialized to 00.0 cents.
NOTE: Regardless of the resolution previously chosen under the RUN screen, temperament and stretch file editing is always
carried out in the highest (0.1 cent) resolution of the tuner.
The octaves of the stretch file are numbered from 0 through 7. These need not correspond directly to the 0 to 7 bands on
the strobe disc of the tuner. In fact, the preset piano stretch files begin (at OCTV=0) with the octave below the one shown
on Band 0 of the strobe disc (with Display +2/-1 at “normal” viewing). This is to permit the definition of the low A, A#,
and B on 88-note pianos (as well as the entire extra—and really cool—low octave on the those decked out imperial grands!)
at the expense of omitting the highest “C” on most pianos. You could even define note offsets for the highest piano notes
in OCTV=0 if you want and work backwards. OK, that’s probably asking for trouble—still there are other good reasons for
making stretch octaves independent of “real” frequencies. For the now in vogue guitar stretch intonations, for example, you
could apply all the note offsets within two consecutive octave numbers (because you need two distinct Es in traditional
tuning of the six-string) rather than spread them out into their “proper” octaves. This saves keystrokes both in creating the
stretch file and in accessing the notes when tuning.
Another apparently strange phenomenon you will note in editing stretch files is, while editing always proceeds from C
through B within octaves, editing always begins at OCTV=4, then proceeds to OCTV=3, 2, 1, and 0; then jumps to OCTV=5,
then 6, and finally OCTV=7.
STRCH = BG 1 KEY= C
NOTE= B —01. 3 ¢
OCTV= 4
DONE NEXT
1 2 3 4
4
STRCH = BG 1 KEY= C
NOTE= C 00. 0 ¢
OCTV= 3
DONE NEXT
1 2 3 4
Example of Octave Sequence When Editing Stretch (or Temperament) Notes
This is to mimic a common practice of tuning a center piano octave, then proceeding downward (for tensioning purposes),
and finally completing the upper octaves. The important point is to be careful when entering your stretch file so that you
are confident that you placed your offsets where you think you did!
As you can see from the flowchart, changing the cent value for the current note offset is accomplished with the UP ARROW
and DOWN ARROW buttons next to the screen. Once we set the desired offset for the displayed note, we may either hit
button “4” (NEXT) or the ENTER button. Either one temporarily saves our offset selection and automatically points the