Polycom EF2201 Brochure & Specs page 12

Matrix Questions
Why does a 12-input/12-output device have a 27x18 matrix?
There are 12 physical analog inputs into the Vortex EF2280 and there are an additional 14 digital inputs that can come
from the high speed digital EF Bus. Finally the signal generator (white noise, pink noise, or sinusoids) can be mixed into
any output. This accounts for the 27 inputs to the matrix. On the output side there are 12 physical analog line level
output signals, 4 digital bus signals (W, X, Y, and Z), and 2 echo cancellation reference signals that are used internally for
the acoustic echo cancellers. This accounts for the 18 outputs from the matrix.
Why cross point gains?
We wanted the Vortex to be as flexible as possible and felt that a simple router instead of a matrix was too limiting.
Cross point gains allow you to map any input to any output with arbitrary gain. An input can be used in many different
outputs with different gains each time the signal is used.
What can I do with them?
With arbitrary cross point gains you can do much more interesting conferencing with sound reinforcement designs. Also,
as we'll see with the sub-matrix, the cross points in the sub-matrix allow you to very easily share resources such as
codecs and other signals across all linked Vortexes.
Why is that different?
Previous products gave you no choice in how inputs were mapped to outputs. You took the full strength audio or possibly
mapped full strength inputs into a sub bus and then you could use the sub bus. That technique forced you to think
differently – why not just map the inputs to the outputs with whatever gain you want? This is what the Vortex allows
you to do.
Can I use all inputs and outputs?
Yes. All microphone/line inputs, the A, B, C, and D inputs, the gated microphone 1-8 signals, the 14 bus signals and the
signal generator can be used as inputs. Any of these signals can be mapped to any output with an arbitrary cross point
gain. The exception to this is that the expansion bus inputs cannot be mapped to the same expansion bus output, i.e.,
the X bus input cannot be mapped to the X bus output.
How do I change a matrix cross point?
The easiest way is to use the Conference Composer software and left click on the matrix cell you would like to change.
To do this manually with an RS-232 command, you would simply use the MGAIN command with the row and column of
the cross point you would like to change and then specify the value. Assuming a Vortex EF2280 has a device ID of 0, the
following command sets the cross point of input 5 to output A to –6dB: F00MGAIN5,A,-6. That's all there is to setting
cross point gain values. You can increment (or decrement) the cross point gain with the MGAIN command too.
F00MGAIN5,A,>3 increments the cross point gain by 3dB. (<3 decrements the gain by 3dB).
Processing Questions
What processing is available?
The processing in the Vortex includes the NOM attenuation on all 12 outputs, the acoustic echo cancellation, the noise
cancellation, automatic gain control, 5 parametric filters for each of the inputs and outpus, and adjustable delay on the
output channels. The parametric filters include highpass, lowpass, notch/boost, high shelf, low shelf filters, and
Linkwitz-Riley lowpass and highpass.
10