Envelope Number; Number Of Steps; Size Of Step; Time Per Step - AMSTRAD cpc 6128 User Instruction

Envelope Number
This is the reference number (between 0 and 15) given to a particular volume
envelope so that it can be called up in the SOU N D command.
Number
of Steps
This parameter specifies how many different steps of volume you want the sound to
pass through before it ends. For example, in a note which lasts 10 seconds, you may
wish to have 10 volume steps of 1 second each. In such a case, the <number of steps>
parameter used should be 1 0.
The available range of <number of steps> is 0 to 1 27.
Size of Step
Each step can vary in size from a volume level of 0 to 1 5 with respect to the previous
step. The 16 different volume levels are the same as those you will hear in the
sou
N D
command. However, the <size of step> parameter used can be between
-1
28 and
+
1 27; the volume level re-cycling to 0 after each 1 5.
Time per Step
This parameter specifies the time between steps in 0.01 second (hundredths of a
second) units. The range of <time per step> numbers is 0 to 255, which means that the
longest time between steps is 2.56 seconds (0 is treated as 256).
Note therefore, that the <number of steps> parameter multiplied by the <time per step>
parameter shouldn't be greater than the <duration> parameter in the SOU N D
command, otherwise the sound will finish before all the volume steps have been
passed through.
(In such a case, the remaining contents of the volume envelope are discarded.)
Likewise, if the <duration> parameter in the SOU N D command is longer than the
<number of steps> multiplied by the <time per step> ,'the sound will continue after all of
the volume steps have been passed through, and will remain constant at the final
level.
To experiment with the volume envelope, type in the following program:
10
env
"1,10,1,100
20 sound 1,142,1000,1,1
run
Foundation Course Chapter 1 Page 71