Hammond Sk PRO, Reference Manual

Page: 353 / 624

CUSTOM SETS - Tone Wheel
335
From the screen shown on the previous page, press the PAGE “ u ”button once. Page 3 of the CUSTOM EDIT
- TONE WHEEL FUNCTION Mode should now display. The Information Center Display should look like this:
t
EACH WHEEL
This Parameter Menu Page allows you to change the characteristics of all 96 tone wheels individually.
What Is “Generator Calibration?”
Because each frequency on a Hammond Organ is generated independently and the circuitry and hardware
necessary to generate each tone is quite complex, there is the potential for a great deal of variation in sound from
one frequency to another.
The above diagram shows how a single frequency is generated. As explained on page 25, there is one tone wheel
for each frequency. The number of tone wheels which generate actual frequencies varies with the model.
Organs based on the original Hammond design - the model A and its derivatives (B-3, C-3, etc.) had 91 tone
wheels that sound, while later models such as the “H” series and the X-77 had 96 (the extra five tone wheels
being used to generate higher frequencies). The SK PRO has 108 virtual tone-wheels - 96 manual tone-wheels
plus the 12 tone-wheels for the bass frequencies which play only from the Pedals on a vintage Hammond Organ.
As explained previously, each tone has a magnetized rod associated with it. When the tone wheels rotate, a very
small electrical current is generated in the coil each time a high spot passes the magnet. The strength of the
current determines the loudness of the resulting musical note.
At the Hammond tone-wheel factory, the distance of each magnet to each tone wheel - as well as the number of
windings for each coil - was very carefully controlled to insure that each frequency would play at the correct
volume. In other words, the generator on each tone-wheel organ was very carefully calibrated. However, a
number of third-party technicians would re-calibrate generators to change the sound in various ways - make the
sound brighter, etc. The CUSTOM TONE WHEEL Parameter Menu allows you to “re-calibrate” the digital tone
wheels of your instrument to create exactly the tone quality you desire.
NOTE: In order to use this Parameter, you should already have some idea of the type of sound you want. Also, you
should be prepared that getting the results you want may require some “trial-and-error” before you are satisfied with
the results.
HA<O>
SK PRO Reference Guide