[comp.sys.cbm] Sound In?

js9b+@andrew.cmu.edu (Jon C. Slenk) (12/14/88)

Howdy all!

I saw an advertisement (in sharper image catalog) for a unit that takes voice
input and then gives a smooth, instrumental output. This allows one to play
instruments through humming, singing etc, freeing the person of learning how to
play the real thing.

It struck me that the SID chip is a full synthesizer. Couldn't it be set-up to
do much the same thing, but with greater variety? The chip is designed to work
on input, to modify it, so you can daisy-chain them for complex sounds. How does
the 64 do this? Does it have a port where I could stick a mic and then have an
assembly program take this data and use it to create the output sounds?

Any help (input :-)) would be appreciated!

Sincerely,
Jon Slenk / js9b CMU.

Geoffrey.Welsh@isishq.FIDONET.ORG (Geoffrey Welsh) (12/16/88)

 > From: js9b+@andrew.cmu.edu (Jon C. Slenk)
 > Message-ID: <cXdcoVy00Uo6A9KGEV@andrew.cmu.edu>
 
 > I saw an advertisement (in sharper image catalog) for a
 > unit that takes voice
 > input and then gives a smooth, instrumental output.
 
 > It struck me that the SID chip is a full synthesizer. Couldn't
 > it be set-up to
 > do much the same thing, but with greater variety?
 
   I'm no SID expert, but I'm sure the answer is "no"; at least not 

without extra hardware.
 
   The SID chip's input is not affected by the synthesizer aspect of 

the chip, so you couldn't use it to modulate some other output. If 
I remember correctly, the only thing that you could do to the input 
on the SID chip was pass it through the frequency filter (offering 
high-, low-, band-pass, and notch-reject modes).
 
   In order to modify an incoming signal, you'd have to be using analytical 

hardware (or some basic A/D hardware and analytical software) and then 
re-generate the desired sound from the SID. For more detail on that, 
you'd have to talk to people who've added sound interfaces to their 
64... I only played with the SID briefly when I got my first 64 back 
in '82 or '83.


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aliu@nunki.usc.edu (Alejandro Liu) (12/23/88)

In article <992.23AFEC5A@isishq.FIDONET.ORG> Geoffrey.Welsh@isishq.FIDONET.ORG (Geoffrey Welsh) writes:
>
> > From: js9b+@andrew.cmu.edu (Jon C. Slenk)
> > Message-ID: <cXdcoVy00Uo6A9KGEV@andrew.cmu.edu>
> > I saw an advertisement (in sharper image catalog) for a
> > unit that takes voice
> > input and then gives a smooth, instrumental output.
> > It struck me that the SID chip is a full synthesizer. Couldn't
> > it be set-up to
> > do much the same thing, but with greater variety?
>   I'm no SID expert, but I'm sure the answer is "no"; at least not 
>without extra hardware.

   I am not a SID expert either, but the thing is possible, with some cheap
Hardware aditions.  That is called digitizing.  The problem is that digitizing
takes HUGES ammounts of memory.  So you have two options, record a shorter 
sound or loose sound quality.  Probably, this device you are talking about,
decide to loose sound quality in order to allow longer songs.

>   The SID chip's input is not affected by the synthesizer aspect of 

You don't use the SID chip's input that is connected to the Video Port of
the C-64 to do that though.

>   In order to modify an incoming signal, you'd have to be using analytical 
>hardware (or some basic A/D hardware and analytical software) and then 

The SID chip, also has two A/D converters built in.  Currently, they are used
to read the Paddles.  I am not an electronics wizard, but it is possible to use
them to DIGITIZE a sound input.  (I belive that there were a couple of devices
that use that scheme to digitize sounds, but I think that the company that
built them has gone out of business)
Using that by itself, you will be able to achieve some success in digitizing
sounds, pretty much like a CD, but with a resolution of 4 bits.  The A/D
converters, have 8 bit resolution, but I think most of the SID register are
4 bit only.  Of course, you can then use a program to analyze the data  so
it can be played back using a more elborated way, rather than changing volume
levels.
-- 
 
                    aliu@nunki.usc.edu (Alejandro Liu) 
(Simple .signature, $CHEAP$)