DEFINITION OF TERMS
VORTEX EF2201 Reference Manual 36 Technical Support: 800.932.2774
D
EFINITION
 
OF
 T
ERMS
Acoustic Echo Acoustic echo occurs in a conferencing or distance learning system when the remote 
speech played in the loudspeakers is picked up by microphones in the room and is 
transmitted back to the remote end.  This transmitted signal is a delayed version of the 
original, which causes the echo.
Acoustic Gain Acoustic gain is a term used in conjunction with sound reinforcement.  It refers to 
how much louder the audio is with sound reinforcement compared to without sound 
reinforcement.
Ambient Level The ambient level, also referred to as noise floor, is the background noise heard in a 
room when no one on the near or remote end is talking.
Automatic Gain 
Control (AGC)
Automatic gain control increases or decreases the gain on an audio signal to an 
acceptable value.
Automatic 
Microphone Mixer
A microphone mixer that turns microphone channels on and off based on the signal 
level going into the microphone.
Convergence Rate Convergence rate refers to the amount of echo a line or acoustic echo canceller can 
cancel per unit time, typically expressed in dB/sec.  Better echo cancellers have a 
higher (faster) convergence rate.  This term is typically used to quantify the time it 
takes to completely remove the echo from a conferencing system.  Echo occurs due to 
a complete change of the acoustic environment such as the beginning of a phone call 
in a conference, a change of microphone-speaker placement, or speaker volume 
adjustment.
Crosspoint Mix 
Minus Bus
A mix minus bus allows each device to create a mix of signals without its own.  The 
submix (W, X, Y, Z, or P) inputs to the main matrix are mix minuses.
Echo Canceller An echo canceller estimates the echo in an audio signal by using a reference and pre-
forms processing to eliminate the echo from the signal.
EF Bus The EF Bus is a digital bus that includes the W, X, Y, and Z audio busses as well as 
the echo canceller reference and remote control information.  It can be used to link 
multiple Vortex devices.