The primary applications are in sound reinforcement and conferencing
systems in boardrooms, courtrooms, worship centers, distance learning
systems, hotels and other applications with multiple microphones and loudspeakers.
The design represents a milestone in DSP technology in its basic architecture
and in its processing speed and efficiency.
The challenge in teleconferencing using a sound system on one or both
ends of a conference is to minimize echo heard at the far end caused by
the coupling between loudspeakers and microphones in the local sound system.
As sound from the far end enters the local sound system and is delivered
by the loudspeakers in the local room, it will enter the local microphones
and be sent back to the far-end. At the far-end the listeners will hear
an echo of their own speech. The integration of adaptive gain proportional
auto mixing* with an all new proprietary acoustic echo canceller provides
a remarkable solution that is as easy to install and set up as it is effective.
Echo-free teleconferencing and clean local sound reinforcement is provided
even in poor acoustical environments.
The Lectrosonics DMTH4 shares the large digital matrix bus with other
Lectrosonics DM Series processors to handle a wide range of sound system
requirements from a modest boardroom to large systems with hundreds of
inputs. Multiple units can be stacked with multiple DM processors to handle
very large systems with multiple phone lines.
Extensive control capability is built into the unit with an intuitive
command structure to allow external control with USB or RS-232 connections.
Up to 128 macros can be stored in internal memory. Each macro can contain
up to 64 commands, with 115 characters in each command. A built-in macro
recorder greatly simplifies the creation of and use of macros.
*US Patent 5,414,776