Secrets in This Chapter
Configuring the Sound Card
Manually Configuring the Sound Card
Testing the Sound Card
Playing Audio CD-ROMs
Without a sound card, the PC’s built-in speaker can only play a single note; you can’t even vary the loudness of the note. Luckily, most PCs nowadays come with a sound card—either a separate card or some sound circuitry built into the motherboards—that greatly improves the sound-output capability of the PC. The sound card is an adapter that plugs into a slot on your PC’s motherboard and includes the electronic circuitry needed to play and record sound. You can plug speakers and a microphone into the back of a sound card.
When a microphone is hooked up to the sound card, the card can convert the analog (continuously varying) sound waves into 8-bit or 16-bit numbers, sampling the wave at rates ranging from 4 kHz (4,000 times a second) to 44 kHz (44,000 times a second) and more. Higher sampling rates and a higher number of bits (16) provide better quality, but you need more disk space to store high-quality sound. In addition, the sound card can convert digital sound samples to analog signals you can play on a speaker.
Most sound cards, including the popular Sound Blaster, also support MIDI (Musical Instrument Digital Interface) commands, in addition to recording and playing back waveform sound. MIDI is commonly used to record and play back musical sounds that a synthesizer can create. (Most sound cards have built-in synthesizers.)
This chapter describes specific types of Linux-supported sound cards and how you can set up a sound card after you have successfully installed Red Hat Linux.