This is just a little snippet, to demonstrate how to print numbers directly to the /dev/dsp and make tones. I've always wondered how to do it, and here is a super simple demonstration. It's just for entertainment value, since it probably uses too much CPU power.
#!/usr/bin/perl
use warnings;
use strict;
use Audio::DSP;
$| = 1;
my $sample_rate = 22050;
my $bits_sample = 16;
my $channels = 1;
my $format = AFMT_S16_LE;
my $buffer = 4096;
my $dsp = new Audio::DSP(buffer => $buffer,
channels => $channels,
format => $format,
rate => $sample_rate);
$dsp->init() || die $dsp->errstr();
############################################################
my $freq_adj = .1;
my $vol = .5;
my $toggle = 1;
while(1){
make_tone($freq_adj, $vol);
if(($freq_adj > 4) or ($freq_adj < .1)){ $toggle *= -1;}
$freq_adj += ($toggle * .001); #higher increment numbers are slower
#0 is pure tone
}
sub make_tone {
my $rad = 0;
my ($freq_adj, $vol) = @_;
while ( $rad < 6.283 ){
$rad += $freq_adj;
my $raw = ($vol*32768) * sin($rad); #max times
my $num = pack( 'V', $raw );
$dsp->dwrite($num);
}
}