Science Fair Project Encyclopedia
The PC speaker is the most primitive sound system used in IBM compatible PCs, and in fact used to be the only one in use in PC games before more technologically advanced sound cards such as AdLib or the Sound Blaster were introduced as ISA plug-in cards around 1990. However, even some years after these sound cards became mainstream and widely used, game manufacturers continued to support PC-speaker-only sound/music in their games in order to maximise their customer base. This was in part due to the fact that sound cards did not originally follow any commonly agreed-upon standard, and were largely incompatible with each other. The PC speaker was the only sound system that could be regarded as universally present.
The PC speaker is characterized by its inability to play more than one tone at once. Because of this, it was often nicknamed a PC beeper or PC squeaker, especially when sound cards became widely available. In spite of its limited nature, the PC speaker was often used in very innovative ways to create the impression of polyphonic music or sound effects within computer games of its era, such as the LucasArts series of adventure games from the mid-1990s. Several programs, including MP (Module Player, 1989), ScreamTracker, Impulse Tracker, and even a Microsoft Windows device driver, could play 4-bit PCM sound through the PC speaker using frequency modulation. However, because of the way the speaker is controlled, these effects often caused noticeable sluggishness and usually failed on computers that were more than a bit faster than those the program was originally written for.
All modern operating systems include a generic sound API, so that applications no longer need to know the specifics of each sound card. Correspondingly, the use of high-quality sound hardware has become commonplace. Now, the PC speaker deals only with low-level warning signals such as start-up errors, though it can still be used to its full potential should the need arise -- as long as it hasn't been reduced to an onboard miniature piezo speaker, whose acoustic properties are so different from the paper cone speakers of old that most of the usual "tricks" don't sound nearly right.
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