Renaissance Theatre
23
Appendix iv
The first message means that piston 1 was pressed on channel 1. The second message indicates that General
piston 10 was pressed.
EXPRESSION: - This is a more complex subject. MIDI expression (Volume) changes are under the broad heading
of "Control Changes." Control changes can be many things from expression, to stops, to "pitch bend" changes for a
MIDI keyboard. Each of these has a separate number to indicate what kind of control change it is. Volume or
expression is control change number seven. The control change data will contain channel information, the type of
control change, and a number for the control change "value." In the case of volume, the control change value would
be between 0 and 127. Since the organ never truly goes to "0" with the expression shoe, the lower limit on the Allen
is approximately 20. In Cakewalk, the expression data might look like this:
TRACK CHANNEL TIME EVENT VALUE DURATION
1 1 X:XXX:XX CONTROL
7
100
1 1 X:XXX:XX CONTROL
7 98
1 1 X:XXX:XX CONTROL
7 96
Here we see that the volume is reducing on channel 1. You will notice on your GW4 organ that many channels are
sent on a single expression shoe. All manual divisions must be sent at some point for your external MIDI devices to
understand expression.
STOPS: - This is even more complex than the expression. We have a "Map" for all organs that will allow the data
recorded on one organ to be played back on another organ. Enclosed is a list of the organ stops and their MIDI
"addresses.” Individual stops are handled by control numbers. MIDI has a "catchall" for anything not specifically
defined by the MIDI standard called "NON-REGISTERED PARAMETERS." These are under control numbers 98
and 99. 99 being the "high" byte and 98 being the "low" byte. "Control 6" is the "on and off" byte: Control 6 with a
value of 127 turns the stop on. Control 6 with a value of 0 turns the stop off. As an example, in the list of stops for
the GW4 you will note that the Great Solo Tibia Clausa 8' is listed as 1,040. "1,040" means that this stop is on
Channel 1 (Great) and its "map" number is 40. If you checked the Primary Tibia 8' on any of our organs, you would
find that it would be "40." The best way to show this is to show you an example in Cakewalk. The first three pieces
of data turn on the Tibia Clausa 8' on the Great. The second three pieces of data turn off the Tibia Clausa 8' on the
Great.
TRACK CHANNEL TIME EVENT VALUE DURATION
1 1 X:XXX:XX CONTROL
99 0
1 1 X:XXX:XX CONTROL
98 40
1 1 X:XXX:XX CONTROL
6
127
1 1 X:XXX:XX CONTROL
99 0
1 1 X:XXX:XX CONTROL
98 40
1 1 X:XXX:XX CONTROL
6
0
