QBasic has two ways of making sounds.
- SOUND command
- PLAY command
The SOUND command produces sound of a specific frequency for a specific duration from the PC Speaker. Only one sound can be played at a time. If multiple SOUND statements are issued sequentially, every statement after the first will not execute until after the previous one finishes.
SOUND f, d
- f - Frequency in Hertz
- d - Duration in ticks
SOUND 100 , 20
Plays a 1000 hertz wave for 20 ticks. One second is about 18.2 ticks, so 20 ticks are about 1.1 seconds.
The lowest frequency allowed by QBasic is 37 Hz, which is roughly a D in the 2nd octave. The highest frequency is 32 767 Hz, but this tone can not be heard, because the normal human hearing range ends at 20 000 Hz.
A secondary function of the SOUND command is to use it to control time in a program.
For x% = 1 TO 10 Print x% Sound 32000,18.2 NEXT
This program will print the numbers 1 to 10, with a 1 second delay between each number.
The PLAY command is for playing music. It can only play one note at a time.
More than that the play command can play a complex stored "song" This is accomplished through the use of a song string. For string command detail, see QBasic/Appendix#PLAY.