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:
“As far as I’m concerned, “whom” is a word that was invented to make everyone sound like a butler.”
—Calvin Trillin (b. 1935)
“Al: Ain’t you gonna look back, Ma? Give the old place a last look?
Ma Joad: We’re goin’ to California, ain’t we? Alright then, let’s go to California.
Al: That don’t sound like you, Ma. You never was like that before.
Ma Joad: I never had my house pushed over before. Never had my family stuck out on the road. I never had to lose everything I had in life.”
—Nunnally Johnson (1897–1977)
“Music is a good thing; and after all that soul-butter and hogwash, I never see it freshen up things so, and sound so honest and bully.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)