| dbo:abstract
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- Throughout its lengthy, multi-model lifespan, the Apple II series computers lacked any serious built-in sound capabilities. At the time of its release in 1977, this did not distinguish it from its contemporaries (ex. the TRS-80 and Commodore PET), but by 1982, it shared the market with several sound-equipped competitors such as the Commodore 64, whose SID chip could produce sophisticated multi-timbral music and sound effects. All Apple II models (except the Apple IIGS, a significantly different, albeit backwards-compatible machine) possess a speaker, but it was limited to 1-bit output in the form of a simple voltage the user could switch on and off with software, creating clicks from the speaker each time the state was toggled. By turning the signal on and off rapidly, sounds with pitches could be produced. This approach places extreme constraints on software design, since it requires the CPU to be available to toggle the output at specific frequencies, and all other code must be structured around that requirement. If sound generation code didn't execute at precisely the right intervals, generating specific output frequencies would be impossible. Sound hardware in competing computers consisted of extra chips that generated sounds without continuous CPU involvement, freeing up the CPU for normal code execution. The various third-party add-on devices listed here provide this same capability to the Apple II. (en)
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| rdfs:comment
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- Throughout its lengthy, multi-model lifespan, the Apple II series computers lacked any serious built-in sound capabilities. At the time of its release in 1977, this did not distinguish it from its contemporaries (ex. the TRS-80 and Commodore PET), but by 1982, it shared the market with several sound-equipped competitors such as the Commodore 64, whose SID chip could produce sophisticated multi-timbral music and sound effects. (en)
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