Re: SDDapple: SDL, sound and the Apple ][

["Michael J. Mahon" <mjmahon@aol.com>]

uso wrote:

>I can't use a "click" system with something like SDL, so I need an
>approximator. :/  Last time I tried this, it didn't come out remotely
>sounding like the ][.

The problem is converting a "click" stream into a stream of
samples to be played by the emulation host audio system.

This is best done by recreating the exact waveform of the click
stream (just on or off, but with exact timing) and then running
a digital filter algorithm to limit frequencies to less than the
Nyquist frequency (1/2 the sample rate), then sampling the resulting
wave at the desired sample frequency and sending it to the host
audio playback system.

Unless the digital filtering is done, aliasing will be a serious
problem in the output.

-michael

Music synthesis for 8-bit Apple II's
http://members.aol.com/mjmahon