Sound
The epitome of the Apple II design philosophy was the Apple II sound circuitry. Rather than having a dedicated sound-synthesis chip, the Apple II had a toggle circuit that could only emit a click through a built-in speaker or a line out jack; all other sounds (including two, three and, eventually, four-voice music and playback of audio samples and speech synthesis) were generated entirely by software that clicked the speaker at just the right times. Not for nearly a decade would an Apple II be released with a dedicated sound chip (though with six expansion slots, users could add sound functionality via a soundcard like the Mockingboard). Similar techniques were used for cassette storage: the cassette output worked the same as the speaker, and the input was a simple zero-crossing detector that served as a relatively crude (1-bit) audio digitizer. Routines in the ROM were used to encode and decode data in frequency-shift keying for the cassette.
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Famous quotes containing the word sound:
“There is a sound of music echoing
Through the open door
And in the field there is
Another sound tinkling in the cotton:
Chains of bondmen dragging on the ground.”
—Arna Bontemps (1902–1973)
“There have been many stories told about the bottom, or rather no bottom, of this pond, which certainly had no foundation for themselves. It is remarkable how long men will believe in the bottomlessness of a pond without taking the trouble to sound it.”
—Henry David Thoreau (1817–1862)
“We can say that the sound is the primary object of the act of hearing, and that the act of hearing itself is the secondary object.”
—Franz Clemens Brentano (1838–1917)