For example, although some distortion may be eliminated, certain percussion sounds will be robbed of their characteristics. The LED filter changes the way these high frequencies are treated by the system, but by using the LED OFF command, you can recapture the essential quality of many instrumental sounds.
The difference made by the LED filter can be clearly heard in the following example:
E> Load "AMOSPro_Examples:Music/Music.Abk"
Music 1
Do
If Mouse Key=1 Then Led On: Print "LED ON!"
If Mouse Key=2 The Led Off : Print "LED OFF"
Loop
Audio quality is very much an individual choice, and the LED filter will sound more pleasing with certain sequences, but distorted with others. Warbling the filter on and off can also give some interesting effects.
The name LED derives from the light-emitting diode that activates the power light on your Amiga. When the LED filter is toggled off and on, this light is also turned off and on to indicate the status of the filter.
VUMETER
function: test volume of a voice
volume=Vumeter(voice)
Volume meters (Vu-meters) are a familiar sight on the control panels of audio equipment. AMOS Professional is not only able to monitor the volume level of any selected voice number from 0 to 3, it can also use the value of the volume intensity to make graphics dance around in response to the intensity of a soundtrack!
The value returned is given as the volume intensity, ranging from silence (0) up to full volume (63).
The best way to understand the effect of all the commands in this Chapter is to hear them working. Be sure to try out all of the demonstration programs that are available via the HELP feature.
Playing music
The AMOS Professional music system allows backing tracks to be added to any program. Music
can be created from a variety of sources, including original samples and compositions, which are
explained in the following two Chapters. These backing tracks are converted into the AMOS
Professional format, and held in the Music Bank.
Music tracks are loaded with the MUSIC command, volume is controlled by MVOLUME, and speed by MVOLUME. Individual music passages can be halted using the MUSIC STOP instruction, and all music is halted by MUSIC OFF.