Advanced System Configuration; Display 2.2 - Introduction - Martin Audio MLA MINI Advanced User's Manual

MLA MINI
ADVANCED USER GUIDE

ADVANCED SYSTEM CONFIGURATION

Display 2.2 – Introduction
Display 2.2 is a version of Martin Audio's MLA/MLA Compact Display 2.2 system design
application, re-versioned specifically for the MLA Mini system. Display 2.2 should always be
used when the requirements of the venue call for a MLA Mini System configuration larger
than the minimum 4 x Mini + MSX per-side. It should also be used with minimum system
configurations if the venue is not suitable for any of the factory Presets to be used.
Display 2.2 is used in conjunction with Vu-Net and an MLA Mini system to calculate i) the inter-
cabinet angles to be used when rigging the system, and ii) the DSP parameters to optimise the
loudspeaker management system. These parameters can then be quickly and easily uploaded to
the hardware using Vu-Net, either directly into an MSX via a USB connection, or via the U-Net
system network. Display 2.2 also provides an accurate prediction of the system response in the
venue.
The application has a straightforward, logical workflow; in fact, it does not allow the user to skip
ahead in the design sequence and it is necessary to complete each stage in the correct, logical
order.
Display 2.2 uses numerical optimisation to calculate the correct cabinet angles and DSP
coefficients for the particular venue scenario. Taking the cabinet angles as an example, this
means that it tries every combination of possible values, checking the result by comparing the
computer model of the array response to the desired response until it arrives at the closest match.
In the case of the cabinet angles, it has the facility to "polish" the array further, by performing
a second pass, thus fine-tuning the array angles. Although highly complex, this process only
takes a few minutes, certainly no longer than a conventional line-array prediction application.
When the cabinet angles have been calculated, the array can be rigged. While this is being
done, the second stage of the optimisation process can be executed. This also uses numerical
optimisation, but now works through the EQ, FIR, gain and phase parameters available in the
DSP, evaluating all possible combinations until the output response is obtained which is as close
as possible to the desired response. With a large array and complex venue this process may take
up to ten minutes to complete, however, this will be far quicker than the time it takes to rig the
arrays so should not impact on the show build. The computer model used by Display 2.2 is one
of the most accurate yet devised for any audio system and achieves predictions within 1 dB of
actual measured parameters.
In touring applications, a Display 2.2 design can be completed offline beforehand for each
venue. With drawings of the space and details of the flying positions and trim height of the
arrays, the rigging design and DSP parameter calculations can be performed off-site, which
makes set-up much quicker and efficient.
A note about Numerical Optimisation
Numerical Optimisation is an easily misunderstood concept; some people assume that it is some
sort of "averaging" procedure, resulting in a "compromise". This is not the case.
Multicellular systems have been made possible by the parallel development of a highly accurate
computer model of the system, which works in conjunction with the precision acoustic design
of the cabinets. Many factors affect an array's performance: the specification of individual
drivers, the horn design, the angle between enclosures, the number of enclosures and so on.
Martin Audio have taken software analysis of array performance to the most advanced level yet
achieved; this includes boundary effect modelling, which takes into account the effect that every
cabinet in an array has on a single driver; essentially each individual cabinet can be considered
as having a baffle extending above and below it formed by the other enclosures in the array. For
cabinets in the middle of the array this is fairly symmetrical, but for cabinets towards the top and
bottom it becomes more and more asymmetric, which has a significant effect on the individual
module performance and therefore the overall array performance.
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