[fpc-pascal] simple sound implementation

Daniël Mantione daniel.mantione at freepascal.org
Sun Sep 2 13:33:15 CEST 2007

Op Sun, 2 Sep 2007, schreef Marc Santhoff:

> Am Sonntag, den 02.09.2007, 10:32 +0200 schrieb Daniël Mantione:
> > 
> > You can set the bell frequency using write(#27'10;freq') and the duration 
> > using write(#27'10;duration'), where freq is in Hz and duration in 
> > milliseconds. Then ctrl+g to ring the bell. It is possible to play music 
> > this way.
> Hey, I like control sequences for this task!
> I understand this as controlling the noise a write(#07) makes, pretty
> easy. I'll try it.
> Ahem, maybe you know how to control the volume, too?

In the original IBM PC the speaker was directly connected to the 8254 
timer chip, therefore there exists no volume control.

In modern PCs, the PC-speaker is often rerouted through the sound card, 
where it can be controlled using the mixer. You use the OSS/ALSA mixer API 
in such case.

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