Apple Final Cut Pro 7 - Manual (Page 208)

XLR Connectors
These are the most common professional audio connectors. They almost always carry a
balanced signal. Many cables use an XLR connector on one end and a 1/4" TRS connector
on the other. The signal may be microphone level (when using a microphone) or +4
dBu/dBm (professional) line level.
XLR connector
Digital Audio Connectors and Signal Formats
Although digital audio signals are completely different from analog audio signals, the
same connectors are often used for convenience. For example, an XLR connector can be
used to carry an analog audio signal or an AES/EBU digital audio signal.
AES/EBU
The AES/EBU digital audio specification was jointly developed by the Audio Engineering
Society (AES) and the European Broadcasting Union (EBU). AES/EBU audio signals typically
use XLR connectors, but 25- or 50-pin D-subminiature connectors can also be used for
multiple channels on interfaces or mixers.
Traditionally, AES/EBU sample rates were limited to 44.1 and 48 kHz at up to 24 bits per
sample. However, a “dual wire” mode allows some equipment to pair AES/EBU connectors
to increase the sample rate. Some newer devices also support “single wire” mode with
sample rates up to 192 kHz.
S/PDIF
Sony/Philips Digital Interface Format (S/PDIF) is a consumer-level variation of the AES/EBU
digital audio protocol. S/PDIF audio data can be transmitted several ways, including:
• Via coaxial cables with an RCA connector
• Via optical TOSLINK
Connectors for S/PDIF signals are found on most consumer digital equipment, such as
DAT recorders, CD players, DVD players, MiniDisc equipment, and some audio interfaces.
Dolby Digital (AC-3)
Dolby Digital (AC-3) is a compressed digital audio signal format used for transmission of
5.1-channel surround sound. Mono and stereo signals can also be carried in this format.
Typically, this audio signal is embedded within a S/PDIF signal and carried via TOSLINK
or coaxial cables with RCA connectors.
208 Chapter 12 Connecting Professional Video and Audio Equipment