Meyer Sound MTS-4A Operating Instructions Manual page 11

A D L F
RRAY ESIGN FOR OW
Since the MTS-4A contains sub and low frequency drivers, in
addition to mid and high drivers, array design for the MTS-4A
must incorporate the different array response of high and low
frequencies. The beam width for a single speaker widens as
the frequency decreases. Frequencies below 125 Hz are mostly
omnidirectional while higher frequencies are more directional.
NOTE: H and V are abbreviations for horizontal and vertical.
The low frequencies of adjacent arrayed speakers exhibit
on-axis addition and off-axis cancellation, resulting in a
narrowing of coverage in the dimension in which they are
arrayed. A H array of two MTS-4As narrows the H coverage
without affecting the V coverage. A V array of two MTS-4As
narrows the V, without affecting the H coverage. In both
cases, there is 3 to 6 dB SPL of on-axis low frequency (LF)
addition compared to a single MTS-4A. Due to the larger
distance between LF drivers in V, compared to H arrays, the
V coverage narrows at a faster rate than does the H coverage
for H arrays, given the same array size and adjacent speaker
placement.
Increasing the number of MTS-4As in the array increases the
LF directional control. A properly designed V array steers
low frequencies to include balconies and upper tiers, while
a H array focuses low frequencies for longer throw distances
without interacting with the walls.
L
OADING
One of the most important factors governing LF response is
speaker placement with respect to adjacent surfaces. The MTS-
4A gains significant LF power by coupling with nearby floors
and walls. Half-space loading describes a speaker coupling
with one surface. Speakers placed on the floor benefit
from half-space loading, while flown speakers in free-space
Number of Horizontal
MTS-4As @ Angle
Coverage
H V
Vertical Rows of MTS-4As
@ Angle
1 70˚ 60˚
2 @ 0˚ (LT) 70˚ 30˚
2 @ 15˚ 70˚ 50˚
2 @ 30˚ 70˚ 90˚
Number of Horizontal
MTS-4As @ Angle 4 @ 15˚
Coverage
H V
Vertical Rows of MTS-4As
@ Angle
1 100˚ 60˚
2 @ 0˚ (LT) 100˚ 30˚
2 @ 15˚ 100˚ 50˚
2 @ 30˚ 100˚ 90˚
REQUENCIES
MTS-4A Array Coverage and Maximum SPL
1 2 @ 15˚
M ax Peak Coverage M ax Peak Coverage
dB SPL H V dB SPL H
140 50˚ 60˚ 146 60˚
146 50˚ 30˚ 152 60˚
145 50˚ 50˚ 151 60˚
143 50˚ 90˚ 149 60˚
4 @ 30˚
M ax Peak Coverage M ax Peak Coverage
dB SPL H V dB SPL H
151 140˚ 60˚ 148 190
157 140˚ 30˚ 154 190
156 140˚ 50˚ 153 190
154 140˚ 90˚ 151 190
(without a nearby wall or ceiling) do not. In general,
subwoofers in half-space generate twice the SPL (+6 dB)
compared to the same number in free-space.
NOTE: SPL values refer to an on-axis measurement position.
The actual SPL addition and narrowing of coverage
varies with frequency and depends on the physical
displacement between cabinets, loading conditions, and
room acoustics.
MTS-4A C
OVERAGE AND
A series of outdoor tests was conducted at Meyer Sound to
determine the coverage angle and on-axis SPL for arrays with
one and two horizontal rows of up to five speakers each, at
numerous splay angles. The measurements were conducted at
a distance of 8 m with half-space loading; on-axis SPL values
were interpolated from 8 to 1 m. The coverage angle for the
array is the result of averaging the –6 dB points from 125
Hz to 8 kHz.
The horizontal angles in the tables below represent the
optimal narrow (15°), middle (30°), and wide (45°)
orientations for the MTS-4A. The vertical splay angles
represent the optimal narrow and wide configurations. 2@0°
LT denotes long throw: the two horns are coupled directly
together (top speaker upside down/bottom speaker upright) to
form a single narrow horn.
The table on this page shows the SPL and coverage angles
that result from grouping the MTS-4A in arrays of up to five
units horizontally and two rows vertically. All splay angles
refer to the angle between cabinet centers.
If this information does not address your application
requirements, contact Meyer Sound to obtain additional
information on array design.
2 @ 30˚ 2 @ 45˚
M ax Peak Coverage M ax Peak
V dB SPL H V dB SPL
60˚ 145 100˚ 60˚ 142
30˚ 151 100˚ 30˚ 148
50˚ 150 100˚ 50˚ 147
90˚ 148 100˚ 90˚ 145
4 @ 45˚ 5 @ 15˚
M ax Peak Coverage M ax Peak
V dB SPL H V dB SPL
60˚ 146 110˚ 60˚ 153
30˚ 152 110˚ 30˚ 159
50˚ 151 110˚ 50˚ 158
90˚ 149 110˚ 90˚ 156
11
M SPL
AXIMUM
3 @ 15˚ 3 @ 30˚
Coverage M ax Peak Coverage M ax Peak
H V dB SPL H V dB SPL
80˚ 60˚ 149 120˚ 60˚ 147
80˚ 30˚ 155 120˚ 30˚ 153
80˚ 50˚ 154 120˚ 50˚ 152
80˚ 90˚ 152 120˚ 90˚ 150
5 @ 30˚ 5 @ 45˚
Coverage M ax Peak Coverage M ax Peak
H V dB SPL H V dB SPL
180˚ 60˚ 148 240 60˚ 146
180˚ 30˚ 154 240 30˚ 152
180˚ 50˚ 153 240 50˚ 151
180˚ 90˚ 151 240 90˚ 149
3 @ 45˚
Coverage M ax Peak
H V dB SPL
150˚ 60˚ 145
150˚ 30˚ 151
150˚ 50˚ 150
150˚ 90˚ 148