Roland Sound Canvas SC-8850, Руководство пользователя

Страница: 154 / 256

154
Appendices
Using NRPNs with GS Sound Modules
Included within the various types of Control Changes (often abbreviated as
CC
) is an extended range
known as NRPNs (non-registered parameter numbers). The NRPNs can be used with GS sound mod-
ules to alter various sound parameters, such as those for the vibrato, filters, and envelopes. There are
distinct advantages to using Control Changes rather than Exclusive messages when wishing to modify
sounds. They are not as complicated, they are easier to handle, and they do not require a large amount
of data (p.149, p.226). Such Control Change messages include a number (the Control Number) which
specifies the type of function that is to be controlled.
The MIDI specifications do not define any specific functions which can be set using NRPNs. This is be-
cause the NRPNs are intended to serve as a flexible range of controls which can be assigned whatever
parameters are required for a specific device in order to achieve the desired changes in its sounds, or
enhance its expressive capabilities. In contrast, there is another type of extended form of control known
as an RPN (registered parameter number). As their name suggests, RPN functions are all defined (reg-
istered) within the MIDI specifications (p.228).
When using an NRPN, the function (sound parameter) being dealt with needs to be specified by means
of the numeric values that are supplied for the NRPN MSB (Controller No. 99) and NRPN LSB (Con-
troller No. 98). By then sending the appropriate value for Data Entry (Controller No. 6), the change in
the specified sound parameter is accomplished.
Note that instead of the hexadecimal notation that is used within the
MIDI Implementation
(p.228),
the numbers for the combinations of values for NRPNs that appear in the chart below have all been con-
verted to decimal.
NRPN NRPN Range Function
MSB LSB
1 8 0–64–127 Vibrato Rate *1 (p.65)
1 9 0–64–127 Vibrato Depth *1 (p.65)
1 10 0–64–127 Vibrato Delay *1 (p.65)
1 32 0–64–127 TVF Cutoff Frequency *1 (p.66)
1 33 0–64–127 TVF Resonance *1 (p.66)
1 99 0–64–127 TVF&TVA Envelope Attack Time *1 (p.67)
1 100 0–64–127 TVF&TVA Envelope Decay Time *1 (p.67)
1 102 0–64–127 TVF&TVA Envelope Release Time *1 (p.67)
24 rr 0–64–127 Drum Instrument Pitch Coarse *1
Alters the pitch of individual percussion instruments in the drum
Part.
26 rr 0–127 Drum Instrument TVA Level
Alters the volume of individual percussion instruments in the
drum Part.
28 rr 0,1–64–127 Drum Instrument Pan
Alters the panning for individual percussion instruments in the
Drum Part. A setting of
0
provides random panning, while
1
se-
lects the leftmost position,
64
the center, and
127
places it at the
rightmost position.
29 rr 0–127 Drum Instrument Reverb Send Level
Sets the reverb depth for individual percussion instruments in the
Drum Part.
30 rr 0–127 Drum Instrument Chorus Send Level
Sets the chorus depth for individual percussion instruments in the
Drum Part.
31 rr 0–127 Drum Instrument Delay Send Level
Determines the amount of delay for individual percussion instru-
ments in the Drum Part (SC-88/SC-88 Pro/SC-8850 only)
For example, let’s say that you want to alter the TVF Cutoff Frequency. First, you need to assert that it
is the TVF Cutoff Frequency that you wish to control by sending the appropriate NRPN MSB and
NRPN LSB combination. The value for Controller No. 99 is the NRPN MSB, and that for Controller No.
98 is the NRPN LSB. So, you would transmit these values:
Controller No. 99: 1
Controller No. 98: 32
The SC-8850 has thus been made aware that it is the TVF Cutoff Frequency that you are going to
change. To go ahead and make the actual change, you would then use the Data Entry Control Change
message to supply the new value (xx) for the TVF Cutoff Frequency.
Thus, you would send:
Controller No. 6: xx
As a result of transmitting the above three controller values, the TVF Cutoff Frequency will have been
altered, and the timbre of the instrument selected for that Part should sound differently.