Vortex Media VTX 1000 - Manual (Page 81)

mix-minus which allows the user to work with a simple mix-minus sum of all the other devices. If more
complicated mixing from other devices is required, any of the matrix rows can have arbitrary cross points
gains. Each one of the 8 inputs represents a signal from another unit that is maintained in its discrete form
until this submatrix. Here you decide which signals to pull off of the bus, what mixes to create, and what
gain or attenuation values to assign to each one of those signals.
The Vortex EF2201 only transmits and receives audio on the P Bus. For each channel that the device
transmits on, there is an automatic mix-minus performed so that one cannot create a loopback on the EF
Bus. This restriction is based on the device ID of the unit. Using the above screenshot as an example, the
device ID of the Vortex EF2201 is 00. As a result, the PB0 cross-points are grayed out.
Since the Vortex EF2201 does not transmit on the W, X, Y, or Z busses, there are no grayed out cross-
points. Let's look at the 8 signals WB0-WB7. These signals are from 8 other Vortex devices. The WB0-
WB7 inputs can be assigned to one of the three submixes that are available for each bus channel. This lets
you create one overall mix at 0 dB to send to a codec or phone hybrid, and two other submixes for sound
reinforcement applications. The same logic can be extended to the P, X, Y, and Z busses with the exception
that the P bus cross-points will always be grayed out based on the device ID of the unit you are working
with.
The routing here is fairly straightforward. We do not need discrete mixes of all the microphones in the
system so it is OK to make mixes of all microphones in the system. We need to make sure that the Program
Audio signals are kept separate from any other signals so that those signals can be attenuated before those
signals are sent to the far side of the telephone call (see the Matrix Mixer for more information on why that
made be necessary).
Matrix Mixer
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