Creating A Tone Envelope - AMSTRAD cpc 6128 User Instruction

Line 20 specifies a SOU N D with a tone period of 1 42 (international a), lasting for 10
seconds with a start volume of 1 , and using volume envelope number 1, conisting of
10 steps, raising the volume'ofeach step by 1, every 1 second (100 x 0.01 second).
Change line 1
0
in each of the following ways and then run to hear the effect of
changing the envelope:
10 env 1,100,1,10
10 env 1,100,2,10
10 env 1,100,4,10
10 env 1,50,20,20
10 env 1,50,2,20
10 env 1,50,15,30
And finally try this:
10 env 1,50,2,10
You will 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 volume varied was only 5 seconds, but
the <durati0n> parameter in the SOUND command in line 20 was 1000, i.e. 10
seconds.
TrY.' experimenting yourself, to see what type of sounds you can create.
If you wish to create a more intricate volume envelope, the 3 parameters: <number of
steps>, <size of step> ,<timeperstep>mayberepeatedattheendofthe ENV command
up to 4 more times, to specify a different 'section' of the same envelope.
Creating a Tone Envelope
The tone envelope command is ENT. In its simplest form, the command has 4
parameters: The command is typed in as:
ENT <envelope number> , <number of steps> , <tone period of step> , <time per step>
Once again, let's look at the parameters one by one.
Envelope Number
This is the reference number (between
0
and 1 5) given to a particular tone envelope
so that it can be called up inthe SOU N D command.
Chapter 1 Page 72
Foundation Course