The different types of computers where multimedia applications will be applied range from personal computers based on x86 family without any audio output hardware in the low price region and RISC-based workstations equipped with audio input and output hardware and digital signal processors designated for audio processing. In the low cost region a lot of suppliers sell additional hardware for audio output. The quality of the audio output ranges from cheap hardware with 8-bit resolution and a sampling frequency of 8 kHz up to cards with two and four audio channels with a 16-bit resolution and up to 48 kHz sampling rate. Most of these sound cards are also equipped with hardware for the synthesis of sound. These built in synthesizers support the GMIDI (General Musical Instrument Digital Interface) which is an extension of the MIDI protocol. In the workstation market most of the workstation like SUN Sparc 20 and Indigo use multimedia codecs which allow sampling rates from 8 kHz to 48 kHz, 8- and 16-bit resolution and two channel audio input and output. With this hardware sampled sound stored in files on the harddisk or CD-ROM or Audio-CDs can be play back. Additional MIDI hardware for sound generation can be connected if the serial port supports a transmission rate of 31.25 KBaud. Depending on the computational power of the CPU or signal processing hardware sound may be manipulated or synthesized on-line. Sound is either presented via the built in loudspeaker or headphones. Loudspeaker may be built in the monitor or in separate boxes. Most hardware realizations only use one speaker but some Apple computers have two speakers built in the monitor for stereo sound output. These overview of existing hardware shows that there is great diversity in the use hardware platforms and which results in big differences in perceived quality and the amount of information which can be transmitted. The future development will lead to sound output with two channels in HiFi-quality with designated hardware for signal synthesis and signal processing.