Telos TWOx12 - Audio Processing and Feedback Control

TELOS TWOX12 USER’S MANUAL
DETAILED CONFIGURATION & REFERENCE
CHAPTER 7 138
7.5 System Audio Processing and Feedback Control
7.5.1 Send Audio Processing
The TWOx12’s send audio processing consists of the following functions:
• Sample rate conversion
• High-pass filter
• Frequency shifter
• Send equalizer
• Send AGC/Limiter
Sample Rate Conversion
AES/EBU sources are sample rate converted to the TWOx12’s internal sample rate
of 48kHz. 48Khz sources are re-clocked to the TWOx12’s internal clock (derived
from the ISDN clock if at least one ISDN BRI is present).
High-Pass filter
A high pass filter with a 250 Hz crossover frequency improves hybrid performance
and enhances intelligibility by removing unnecessary low-frequency information
from the audio present at the TWOx12’s input. This function is not defeatable.
Frequency Shifter
The frequency shifter (pitch shifter) inserts a small, unnoticeable, shift in frequency
to the send audio to prevent feedback buildup when the system is used with open
speakers. See below for additional considerations regarding feedback control.
Send Equalizer
Applies equalization to the audio sent to the caller. Choices are:
• Off - No equalization (default)
• On - Equalization for speech
Enabling this equalizer (On setting) simulates a telephone handset microphone, and
will improve intelligibility. Sometimes high-quality studio microphones sound “too
good” and the low-frequency audio they pick-up can sound unnatural on a telephone
handset.