Polycom EF2201 Brochure & Specs page 44

When Mix-Minus is not enough
The example in the previous section showed how the expansion signals (P, W, X, Y, and Z) from multiple Vortex devices could be
used to send signals from one device to another.. What if you don't want to use a mix of all the W signals from the linked devices,
but only want the W signal from device 2? What if you just want the Y signal from one of the devices, such as from device 0, but
not from device 7? The answer is in how the sub-matrix is used.
Figure 19 shows the 8 signals that are part of the P, W, X, Y, and Z busses. Each of these 8 signals from the 8 devices with device
id's 0, 1, ... 7 are denoted WB0, WB1,..., WB7 for the W bus, XB0, XB1,..., XB7 for the X bus and so forth. The last digit on these
signals represents the device id of the Vortex that originally put the signal on the bus. So WB0, XB0, YB0, and ZB0 are the bus
output signals from Vortex EF2280:00. Each mini-matrix for W, X, Y, and Z has three outputs which go to the main matrix: WM0,
WM1, WM2, XM0, XM1, XM2, YM1, YM2, ZM1, and ZM2. The mini-matrix for the P bus has only two outputs PM0 and PM1.
You can arbitrarily mute or change the gain on the bus signals (PB0, PB1, ..., PB7, WB0, WB1..., ZB7) as you create the
combination signals PM0, PM1, WM0, WM1, ..., ZM2 The signals PM0, PM1, WM0, WM1, ..., ZM2 become inputs to the main
matrix and can be used like any other input and output to the main matrix. The actual bus signals PB0, ... are not affected by using
different crosspoint gains, only their use in creating the combination signal PM0, ... is affected by setting a crosspoint gain or
muting the particular bus input signal.
Figure 21 shows an example of how the different cross point gains on the bus signals can be useful. Assume we have four zones
that we would like to do conferencing and sound reinforcement with 4 microphones per zone as shown in the table diagram in
Figure 21. The sound reinforcement levels that we would like in adjacent levels are shown in Figure 23. We can easily accomplish
this goal by having both Vortex EF2280's put four microphones on the W bus and four microphones on the X bus. Each of these
busses contains NOM information, so the appropriate overall gain and automixer performance will be maintained. By entering this
design into InstantDesigner release 2.0, we can automatically create the appropriate bussing, matrix configuration, and wiring
solution as will be described below. The automatically created main matrix is shown in Figure 25.
Z 1 Z 4
Z 2 Z 3
ONE ONE ONE
ONE
Figure 21. A conference room table with 32 participants, four speaker zones (two loudspeakers in each zone), and 16 microphones (4 microphones
in each zone).
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