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Digital AudioDigital audio is where the computer is used most like a tape recorder or player. An analog sound source is plugged into the mic or line-in of your sound card, and digital audio software can save it digitally. When a digital audio file is played back, the digital information is sent to the sound card, which converts the digital information back into an analog audio signal that is sent out of the "speaker out" or "line out" of the card.Unlike a tape recorder, though, digital audio software lets you edit the audio fairly easily, and can add a variety of effects to the audio. One problem with digital audio is that it takes a lot of computer power and hard drive space to accurately reproduce analog sound. A typical 4-minute song as an uncompressed audio file would be over 40 megabytes! Because digital audio takes up so much space, there are several compressed formats out there, with mp3's probably being the best known and most popular of them. There are two types of compression. Lossless compression, like Monkey's Audio, retains all the original digital information, so there's no degradation of sound quality. Typically, the lossless formats can reduce the size to almost half the original size. There's also "lossy" compression, where some of the digital information is lost, which degrades the qualtiy of the sound. You can usually adjust the bitrate, or the amount of digital information to be saved, but generally, the higher the quality, the bigger the file.. A typical mp3 file at 128 Kb/s is about 11 times smaller than the original file. So, a 40 MB digital audio file can be made into an mp3 that's less than 4 MBs. Obviously, you can save a lot more mp3 files on your hard drive than uncompressed audio files. |
