Vu-Net - Introduction - Martin Audio MLA MINI Advanced User's Manual

MLA MINI
ADVANCED USER GUIDE
Martin Audio's computer model for its multicellular systems achieves a degree of accuracy that
results in the predicted performance is within 1 dB of measured results.
Numerical optimisation uses the computer model to check the performance expected from a
given mechanical orientation and DSP configuration, and compares the result on the venue slice
(a vertical section through the venue space, in a plane parallel to the stage) with what the system
to needs to achieve. It then tries an alternative option to see if the prediction is closer or to the
desired result. If it is not, it ignores that configuration and uses other angles or EQ curves, trying
successive configurations until it has attempted all possible combinations and has reached a
predicted result as close as possible to the desired performance.
To take an example: consider an initial optimisation which calculates the splay angles. In an
MLA Mini system there are five possible angles available between each cabinet; 0.5, 2, 4,
6.5 and 10°. With a 12-cabinet array there are 48,828,100 possible combinations of angles
between all cabinets. Clearly analysing each of these combinations involves a significant amount
of processing, but even this is minimal compared to the number of calculations required when
running numerical optimisation for the DSP: frequency, bandwidth and gain in every EQ band,
phase and FIR filter parameters must be calculated for each cell in every cabinet in the array.
This is why a powerful PC is required and the EQ optimisation can take up to ten minutes or
so for a large array in a complex arena. Even powerful PCs cannot try all possible combinations
in a reasonable time, so algorithms are used that abandon some calculation "avenues" when
a certain sequence of filter parameters are consistently demonstrating negative results. This
allows highly accurate parameters to be produced within a reasonable time frame.
While this approach is processor-hungry, it is a realistic and practical method for obtaining the
best possible results for an array with so many variables. Attempting to manually adjust several
thousand DSP parameters is unrealistic, however good a system technician believes his ears
might be.
A full description of the operation of Display 2.2 can be found in the "DISPLAY 2.2.0 for MLA
Mini" on page 81.

Vu-Net - Introduction

Vu-Net is the monitoring and control application used with MLA Mini systems (or other MLA
family products). Connection between a PC and the MLA system may be made:
• directly on a one-to-one basis to an MSX sub directly via USB, if USB cable length is less
than 5 m,
• directly on a one-to-one basis to an MSX sub via a Silex Ethernet-to-USB converter, or
• by using a Merlin system processor as a PC-to-network hub. When a Merlin is in use,
interconnection between the various MSX subs in the system is via the U-Net network
protocol.
Vu-Net is also used to upload DSP parameters calculated by Display 2.2 to the MLA Mini
system; system firmware checks and updates can also be carried out.
It is important to realise that once the DSP settings have been uploaded into the system, the
presence or absence of a U-Net network in no way affects normal audio operation; all MLA
Mini systems will continue to pass audio with their last known configuration even without a
operational U-Net network.
A full description of the operation of Vu-Net can be found in the "VU-NET 2.0.0 for MLA Mini"
on page 165
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