# SOUND Statement

#### Purpose:

To generate sound through the speaker.

#### Syntax:

    SOUND freq,duration

#### Comments:

freq is the desired frequency in Hertz (cycles per second). freq is a numeric expression within the range of 37 to 32767.

duration is the desired duration in clock ticks. Clock ticks occur 18.2 times per second. duration must be a numeric expression within the range of 0 to 65535.

Values below .022 produce an infinite sound until the next SOUND or PLAY statement is executed.

If duration is zero, any active SOUND statement is turned off. If no SOUND statement is running, a duration of zero has no effect.

The sound is executed in foreground or background depending on the PLAY statement.

#### Examples:

The following example creates random sounds of short duration:

    2500 SOUND RND*1000+37, 2
    2600 GOTO 2500

The following table shows the relationship of notes and their frequencies in the two octaves adjacent to middle C.

#### Table 5

Relationships of Notes and Frequencies

Note | Frequency |  | Note | Frequency
C | 130.810 |  | C* | 523.250
D | 146.830 |  | D | 587.330
E | 164.810 |  | E | 659.260
F | 174.610 |  | F | 698.460
G | 196.000 |  | G | 783.990
A | 220.000 |  | A | 880.000
B | 246.940 |  | B | 987.770
C | 261.630 |  | C | 1046.500
D | 293.660 |  | D | 1174.700
E | 329.630 |  | E | 1318.500
F | 349.230 |  | F | 1396.900
G | 392.000 |  | G | 1568.000
A | 440.000 |  | A | 1760.000
B | 493.880 |  | B | 1975.500

*Middle C.

By doubling or halving the frequency, the coinciding note values can be estimated for the preceding and following octaves.

To produce periods of silence, use the following statement:

    SOUND 32767, duration

To calculate the duration of one beat, divide beats per minute into the number of clock ticks in a minute (1092).

The following table illustrates tempos requested by clock ticks:

#### Table 6

Tempos Requested by Clock Ticks

Tempo | Notation | Beats/ Minute | Ticks/Beat
very slow | Larghissimo |  |
Largo | 40-66 | 27.3-18.2
Larghetto | 60-66 | 18.2-16.55
Grave |  |
Lento |  |
Adagio | 66-76 | 16.55-14.37
slow | Adagietto |  |
Andante | 76-108 | 14.37-10.11
medium | Andantino |  |
Moderato | 108-120 | 10.11-9.1
fast | Allegretto |  |
Allegro | 120-168 | 9.1-6.5
Vivace |  |
Veloce |  |
Presto | 168-208 | 6.5-5.25
very fast | Prestissimo |  |