QBasic Information Center Tutorials - Events
These tutorials were written to help you get a quick, but thorough, understanding of QBasic -
the scope of the language as well as it's specific capabilities.
Sound
QBasic provides a few features for adding sound to applications.
While generally limited, these features have been adequate to support
an entire generation of DOS-based games.
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| play, beep, sound
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| on play, play
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Simple Sounds
Two of the functions, beep and sound, are very easy methods of
producing a simple sound - a single tone for a limitation duration.
- beep
Used alone, with no arguments, beep simply creates a single
note of short duration - 800 Hz for 1/4 second.
beep
Beep is typically used to acknowledge an event, such as a keypress
or completion of a task.
- sound
With sound, you still get a single note but you can control the
frequency and duration.
sound freq%, duration%
sound 4000, 2 # 2 seconds at 4Khz
These sounds are typically used to differentiate between
specific events - such as a piano programs that gives a
different tone for each key pressed.
Complex Sounds
The play function allows creation of more complex sounds/melodies than
the single note features of beep/sound.
A string of notes and instructions are used by the play function to
create the more complex melodies. Examples of this are given in the
functions reference below.
Sound Functions Reference
Here's a quick reference of the available sound functions, in
alphabetical order.
- on play - enable/disable/suspend play event trapping
on play gosub line # capture play events
play on # enable play trapping
play off # disable play trapping
play stop # suspend play trapping.
events are saved and processed
when event trapping is enabled
- play - plays multiple musical notes
play commandstring% # commandstring% contains play directions
play "CDEFGAB" # 7 notes, default settings
Music$ = "MBo3L8ED+ED+Eo2Bo3DCL2o2A" # melody
play Music$
Music$ = "MBT180O2P2P8L8GGGL2E-P24P8L8FFFL2D" # melody
play Music$
The commandstring$ can consist of one or more of the following
play commands
Octave and tone commands:
Ooctave Sets the current octave (0 - 6).
< or > Moves up or down one octave.
A - G Plays the specified note in the current octave.
Nnote Plays a specified note (0 - 84) in the seven-octave
range (0 is a rest).
Duration and tempo commands:
Llength Sets the length of each note (1 - 64). L1 is whole note,
L2 is a half note, etc.
ML Sets music legato.
MN Sets music normal.
MS Sets music staccato.
Ppause Specifies a pause (1 - 64). P1 is a whole-note pause,
P2 is a half-note pause, etc.
Ttempo Sets the tempo in quarter notes per minute (32 - 255).
Mode commands:
MF Plays music in foreground.
MB Plays music in background.
Suffix commands:
# or + Turns preceding note into a sharp.
- Turns preceding note into a flat.
. Plays the preceding note 3/2 as long as specified.
- beep - sends control string to a device driver
beep # no arguments, cannot control duration
- sound - plays a sound through the speaker
sound frequency%, duration% # single frequency 37-32,767
# duration is clock ticks
(10.2 ticks per second)
If you have any suggestions or corrections, please let me know.
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