- Quad-reference Wideband Acoustic Echo Canceller supporting 3-way Bridging - Two maximum speed grade, 4th generation SHARC® processors* - Dual Codec interfaces - TCP/IP Ethernet Addressable - Fully integrated with ASPEN digital matrix - Adaptive Proportional Gain Automatic Mixing at the Matrix Crosspoints - Third Octave Noise Filter on each channel - Sigma-delta class-D audio power amplifiers
The SPNCWB wideband conference interface makes telepresence and multi-site bridging simple and effective in any conference room, with full bandwidth audio frequency response and a unique Quad-reference AEC. Each conference connection includes a dedicated AEC for fast and reliable echo cancellation:
- Telephone line (POTS) - Codec 1 - Codec 2
The fourth AEC is assignable to any final mix in the matrix for purposes such as noise cancellation (when fed a signal from a sampling microphone).
The AEC converges very fast and will remain converged during double-talk and any signal type, including sine waves, enabled by an advanced DSP algorithm. Cancellation depth increases even with brief signal peaks from the far ends.
The AEC in combination with the patented proportional gain mixing algorithm (US Patents 5,414,776 and 5,402,500) provides outstanding audio quality without echo heard at the far ends. Signals from the far ends of the conference are routed to the local sound system and to three mixes that are used as reference signals by the AEC. Audio from the local microphones (which includes far end audio delivered by local loudspeakers) is routed to the AEC via another final mix for cancellation of the far end signals. After processing, the output of the AEC is routed back to the far ends through the matrix.
Three remote sites can be bridged with a local sound system for a seamless telepresence or audio conference. The far end audio signals participate in the same manner as local microphones connected to the mixer.
A full complement of audio signal processing is provided for all inputs and outputs. In addition, a proprietary NRF (noise reduction filter) is provided on each input to suppress noise in severe conditions. The NRF employs a proprietary noise reduction algorithm using a 1/3 octave analysis and downward expansion. The amount of noise reduction applied to the signal at each input is adjustable from 6 dB to 35 dB as needed for the signal conditions and individual preferences. The process is very effective, with almost no audible artifacts up to about 18 dB. Higher values are available for very poor conditions where noise is extremely high and intelligibility is improved at the expense of artifacts in the audio.
A two channel power amplifier is included for loudspeakers in the local sound system. The power amplifier is driven by final mix outputs from the matrix and has a full set of signal processing, including delay, parametric EQ, compressor and limiter. Class-D amplification with a late generation component provides exceptional efficiency, low heat and excellent audio performance. The amplifiers cannot be damaged by wiring errors or unusual loads.
The processor interconnects with other ASPEN processors via the 1Gbp bus built into all models.