[comp.lang.c] Digitized sound on a PC

raistlin@hobbes.catt.ncsu.edu (Brian Weaver) (11/28/90)

>gordon@osiris.cso.uiuc.edu (John Gordon) writes:
>
>>zhou@brazil.psych.purdue.edu (Albert Zhou) writes:
>>>   I want to output some digitalized sound signal to the speaker. The key-
>>>point I figured out is to control the volume of the speaker. While you
>>>can use "sound" to control frequency, Turbo does not provide direct access
>>>to the speaker. I searched throughout my DOS manual and could not find
>>>a interrupt for speaker. Does anybody have any clue on how to access speaker?
>>	If you are trying to output digitized sound from the internal speaker
>>on a PC, good luck.  The speaker is a very minimal sort of device.  Its only
>>feature is that it can beep at different frequencies.  It has no "voices" or
>>anything of the sort.
>
>I'm not an expert at digitized sound on the PC using Turbo (pascal, c,
>c++ ?), but I beg to differ that it cannot be done at all.  If you
>contact komatsu@uhunix.uhcc.hawaii.edu, you will find that he has done
>exactly that (played back digitized sounds on the PC) in a program
>called REMAC, which will play digitized sounds, created for the
>Macintosh, on the PC.  Dave is the moderator of a sound list for REMAC,
>which has over 15 meg of various sound files such as the Simpsons,
>Star Trek characters, etc.  To be added to the sound list, just put
>the phrase: ADD-ME: <your e-mail address> in your message to him.
>
>If you can create sounds from the speaker at the right frequencies,
>you can create "voices".  The output isn't "super stereophonic high
>quality blah blah blah", but you'll be amazed at how good Robin
>Williams saying "Good Morning, Vietnam!" sounds!
>

There is a person here at NCSU who wrote a program to play digitized sound
on the PC.  What he used was what he called pulsed amplitude modulation.
The voice and sound that you hear in every day life is a bunch of 
superpostioned waves.  What he did was to take the amplitude of the wave
at various points and pulse the speaker so as to produce an extremly
accurate replica (That is the short and simple version).  
He put a copy of the program and documents on how it worked, 
includeing how he did it with the pulsed modulation (i think). 
It is on our ftp Site for anyone, although i can't
remember the site name at the moment (sorry).  If you want a copy just
e-mail me and I will find out the site name.  If there is enough response
I will post the site name here.


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---------------------
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                                         raistlin@hobbes.catt.ncsu.edu