Technical information

Apollo Software Manual Glossary 196
Bit Depth (See “Bit Resolution”)
Bit Resolution Often used interchangeably with “bit depth,” this is a term used to de-
scribe the number of bits used in a digital recording. Apollo converts analog audio and
transmits digital audio with a resolution of 24 bits (thus yielding a theoretical dynamic
range of approximately 145 dB), the highest audio interface resolution in common use
today. (See “Dynamic Range”)
BNC A bayonet-type coaxial connector often found on video and digital audio equipment,
as well as on test devices like oscilloscopes. In digital audio equipment, BNC connec-
tors are normally used to carry word clock signals between devices. BNC connectors are
named for their type (Bayonet), and their inventors, Paul Neil and Carl Concelman. (See
“Word Clock”)
Buffer, buffers, buffering The transference of data in small batches instead of continu-
ously. Buffering induces latency (delay) and is inherent in most digital audio systems.
Bus A signal path that carries more than one signal, e.g., a mix bus, auxiliary bus, head-
phone cue bus, etc.
Channel Input Strip A group of controls that pertain only to the functions contained
within a particular mixer input channel. In most mixing consoles, the “strips” are dupli-
cated for each input.
Class A One design technique used in electronic devices such that their active compo-
nents are drawing current and working throughout the full signal cycle, thus yielding
a more linear response. This increased linearity results in fewer harmonics generated,
hence lower distortion in the output signal.
Condenser Microphone A microphone design that utilizes an electrically charged thin
conductive diaphragm stretched close to a metal disk called a backplate. Incoming
sound pressure causes the diaphragm to vibrate, in turn causing the capacitance to vary
in a like manner, which causes a variance in its output voltage. Condenser microphones
tend to have excellent transient response but require an external voltage source, most
often in the form of 48 volts of “phantom power.”
Clock In digital audio or video, a clock serves as a timing reference for a system. Every
digital device must carry out specified numbers of operations per period of time and at
a consistent speed in order for the device to work properly. Digital audio devices such as
Apollo normally have an internal clock, and are also capable of locking to external clock
routed from other digital devices. In order to avoid signal degradation or undesirable
audible artifacts, it is absolutely critical that all digital devices that are interconnected in
a system be locked to the same clock.
Clock Distribution Refers to the process of routing a master clock signal (either from an
internal clock or an external source) to multiple devices by means of multiple outputs,
thus removing the need to cascade the clock through external devices, which can de-
grade the signal.
Core Audio The audio API for Mac OS X.