The SPNTWB from Lectrosonics combines the boards from the company's SPN812 and the SPNCWB into a 2U rack-mount chassis to provide a complete, stand-alone component for telepresence and audio conference systems. The unit can be used with additional ASPEN processors to add additional inputs and outputs. Setup and adjustments can be made using the control panel software or the front panel LCD interface. Inputs and outputs appearing on the LCD have been consolidated into logical groups to simplify navigation.
The far end audio signals in a conference participate in the same manner as local microphones connected to the processor. Three sites connected via two codecs and a telephone line can be bridged into a single conference as seamlessly as local microphones.
The ASPEN AEC (Acoustic Echo Canceller) provides advanced algorithms developed to address the need for a single acoustic echo canceller that could handle the challenges of multi-site bridging and an unlimited number of microphones. The AEC converges very quickly, and then continues to increase the cancellation depth at every opportunity as a conference continues. Cancellation depth will increase even with brief signal peaks from the far end, and convergence will never be lost with any type of signal or in double talk situations.
The AEC in combination with the patented gain proportional mixing algorithm provides excellent 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 also to a final mix that is used as a reference signal by the AEC. Audio from the local microphones (which includes far end audio from the local loudspeakers) is routed to the AEC via a second 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.
The proprietary noise reduction filter used in ASPEN processors is a third octave dynamic processor which is very effective when applied to the far end Codec and telephone line signals when poor connections occur. An Ethernet port is provided for setup and control via standard network connections, and an RS-232 port is provided for use with remote control systems. The design allows simultaneous, multi-point third party control.
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 parametric EQ, compressor and limiter. Class-D amplification is implemented with a late generation component that provides exceptional efficiency, low heat, excellent audio performance, and cannot be damaged by wiring errors.