Chapter 8 - Tips To Optimize System Performance; Speaker Positioning - Martin LIGHTING DIRECTOR User Manual

CHAPTER 8 - Tips to optimize
system performance
Chapter 2 presented the speaker positions for ideal MLD tracking. In real life it is
sometimes impossible to set speakers on the corners of the stage, at the same height,
and at right angles to each other, because movable trusses, large props, screens or
curtains may block some speakers and deteriorate or stop tracking. In this section we
will cover alternative locations for the MLD speakers.
First, here is the terminology we use:
Stage area —the actual physical stage where the performance or presentation is
taking place. It may or may not be completely covered by the interactive area.
Interactive area —the region where tracking is to take place, defined by the
interactive perimeter. In fact this really refers to an interactive "volume" because the
height of the tracker must be considered also.
Speaker area —the area defined by the speakers on the floor when they are seen
from on top (from a bird's eye view). The speaker area may or may not surround the
interactive area.

SPEAKER POSITIONING

The main issues concerning speaker placement are as follows:
1. Ultrasonic coverage: the whole area of the stage where tracking is to take place
—the so-called "interactive area"— should receive pulses from all four speakers. MLD
speakers have a radiation angle of approximately 80º, so the interactive area should be
within the four "cones" of ultrasound generated by the speakers.
1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1
speaker
0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1
0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1
0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1
0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1
0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1
0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1
0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1
0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1
MLD manual 1.1
80°
beam edge
Figure 42 - Ultrasonic speaker radiation cone.
line of best radiation
beam edge
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