Tone Envelope; Tone Period Of Step - AMSTRAD CPC464 User Manual

5 e n v 1 , 1 0 0 , 1 , 1 0
5 e n v 1 , 1 0 0 , 2 , 1 0
5 e n v 1 , 1 0 0 , 4 , 1 0
5 e n v 1 , 5 0 , 2 0 , 2 0
5 e n v 1 , 5 0 , 2 , 2 0
5 e n v 1 , 5 0 , 1 5 , 3 0
And finally try this:
5 e n v 1 , 5 0 , 2 , 1 0
You wilI notice that half way through the sound, the level remains constant. This is because the
number of steps was 50 and the time between each step was 0.1 second. Therefore the length of time
during which the amplitude varied was only 5 seconds, but the duration of the sound in the sound
command in line 10 was 10 seconds (number 1000).
Try experimenting yourself, to see what type of sounds you can create.

TONE ENVELOPE

The tone envelope command is ent.
This normally has 4 parameters.
The last 3 parameters may appear in any of up to 5 optional envelope sections available. We are only
using one of these here. Further explanation will appear in Chapter 6.
ent envelope number, number of steps, tone period of step, step time.
ENVELOPE NUMBER
This is the number given to a particular envelope so that it can be specified in the sound command.
The range of envelope numbers is 1 to 15.
NUMBER OF STEPS
This is used in conjunction with the step time. For example, you may wish to have 10 steps of 1
second each. The range of step numbers is 0 to 239.

TONE PERIOD OF STEP

The tone period for each step can vary between -128 to +127. Negative steps increase the frequency
of the notes (make the notes higher). The shortest tone period is 0. This must be remembered when
calculating the tone envelope, The full range of tone periods is shown in Appendix VII. The range of
tone period of step numbers is -128 to + 127.