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.
Read more about this topic: Apple II
Famous quotes containing the word sound:
“It is a tale
Told by an idiot, full of sound and fury;
Signifying nothing.”
—William Shakespeare (1564–1616)
“Therefore when thou doest thine alms, do not sound a trumpet before thee, as the hypocrites do in the synagogues and in the streets, that they may have glory of men. Verily I say unto you, they have their reward. But when thou doest alms, let not thy left hand know what thy right hand doeth.”
—Bible: New Testament Jesus, in Matthew, 6:2-3.
From the Sermon on the Mount.
“An old pond—
a frog tumbles in—
the sound of water.”
—Matsuo Basho (1644–1694)