multimedia element (sound)

Sound

Whether used in games to provide "sound effects" or in education titles to teach foreign languages, sound is an important element in a multimedia title. An audio card is used to play digital sounds. The quality of the digital sound is determined by the binary digits (bits) used to represent the sound. A binary digit (bit) is the smallest unit used to represent the coding of data in a computer. The standard is now 32-bit sound.

A kilobit per second (kbit/s or kb/s or kbps) is a unit of data transfer rate equal to 1,000 bits per second. It is sometimes mistakenly thought to mean 1,024 bits per second, using the binary meaning of the kilo- prefix, though this is incorrect.

Most digital representations of audio are measured in kbit/s:

(These values vary depending on audio data compression schemes)

* 4 kbit/s – minimum achieved for encoding recognizable speech (using special-purpose speech codecs)
* 8 kbit/s – telephone quality
* 32 kbit/s – MW quality
* 96 kbit/s – FM quality
* 192 kbit/s – Nearly CD quality for a file compressed in the MP3 format
* 1,411 kbit/s – CD audio (uncompressed, 16 bit samples × 44.1 kHz × 2 channels)

The invention of digital sound recording and the compact disc in 1982 brought significant improvements in the durability of consumer recordings. The CD initiated another massive wave of change in the consumer music industry, with vinyl records effectively relegated to a small niche market by the mid-1990s.

The most recent and revolutionary developments have been in digital recording, with the invention of purely electronic consumer recording formats such as the WAV digital music file and the compressed file type, the MP3. This generated a new type of portable solid-state computerised digital audio player, the MP3 player. Another invention, by Sony, was the minidisc player, using ATRAC compression on small, cheap, re-writeable discs. This was in vogue in the 1990s, and is still popular, especially in a newer, longer playing and higher fidelity version. New technologies such as Super Audio CD, DVD-A, Blu-ray Disc and HD DVD continue to set a very high rate of change in digital audio storage.

DIGITAL RECORDING

This technology spreads across various associated fields, from hi-fi to professional audio, internet radio and podcasting.

Technological developments in recording and editing have transformed the record, movie and television industries in recent decades. Audio editing became practicable with the invention of magnetic tape recording, but the use of computers has made editing operations faster and easier to execute with software, and the use of hard-drives for storage has made recording cheaper. Today, the process of making a recording is separated into tracking, mixing and mastering. Multitrack recording makes it possible to capture signals from several microphones, or from different 'takes' to tape or disc, with maximized headroom and quality, allowing previously unavailable flexibility in the mixing and mastering stages for editing, level balancing, compressing and limiting, adding effects such as reverberation, equalisation, flanging, and much more.

In the 1920s, the early talkies featured the new sound-on-film technology which used photoelectric cells to record and reproduce sound signals that were optically recorded directly onto the movie film. The introduction of talking movies, spearheaded by The Jazz Singer in 1927 (though it used a sound on disk technique, not a photoelectric one), saw the rapid demise of live cinema musicians and orchestras. They were replaced with pre-recorded soundtracks, causing the loss of many jobs. The American Federation of Musicians took out ads in newspapers, protesting the replacement of real musicians with mechanical playing devices, especially in theatres.