Re: [abcusers] Fomula for determining a half step in MgHz...

[Tim Riley]

Bruce Olson wrote:
> Also it came as a surprise to me to find the Basics sound command gives
> square waves at the speaker (ABC2WIN and my ABZ player).

That's because it's simply a speaker connected to the output of a logic
element (in the original PCs, it was a flip-flop), so all you can do is
apply +5V or 0V and use the limited frequency response of the speaker
to filter out some of the upper harmonics.

> Norbeck's AbcMus I haven't examined much, but my trials on A=440 lead to
> an audio signal out as a three part sawtooth for each cycle. The ear
> doesn't seem to much care how close to a sine wave it is, as far as
> calling it 'music' goes.

ABCMus uses the computer's MIDI device, usually a soundcard synthesizer
(using either a wavetable or FM synthesis method) so the output can be
anything you want (within the abilities of the soundcard and its driver).
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