Gregory Weston wrote:
In article <081120052256238969%nobody@nowhere.com>, beavis <nobody@nowhere.com> wrote:In article <john.doggett-CEF56F.19300308112005@News-West.newsfeeds.com>, Bible John <john.doggett@x-files.gov> wrote:One says this in response to a post from the apple forums where a user claims to have been able to record audio in 1985 on his mac.Yes, "a user" was you."Not in 1985, you didn't. The first Macs with built-in audio input were the LC and IIsi, introduced in 1990."That's me.I personally remember recording audio and playing it back way way back during the Apple II days in the 80's.Your memory's failing you. The Apple II (except the GS) could only play clicks through the speaker, unless you added something like a Mockingbird card to it.While this is, strictly, true, that speaker could get surprisingly faithful reproductions of audio signals by varying the frequency of the clicking. I had - still have somewhere I'm sure - a software-only audio digitizer for the Apple II that sampled from the cassette port.
...and even better reproduction by maintaining an ultrasonic pulse rate and varying the duty cycle. My DAC522 gets 5-bit sample resolution at an 11kHz sample rate and a 22kHz pulse rate. Although the dynamic range is limited, for typical sounds it sounds almost as good as 8-bit reproduction. (Programs and examples are on my web site.) Of course, as Matthew has already pointed out, the cassette input port is limited to 1-bit, or "infinitely clipped", sampling. The resulting samples are intelligible, but of very poor "quality, and quite fatiguing to all but ears conditioned to high clipping levels. Sampling with reasonable quality on an 8-bit Apple II requires the addition of an A/D converter board. -michael Music synthesis for 8-bit Apple II's! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it is seriously underused."