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CHAPTER 5
USING MICA WITH SUBWOOFERS
A MICA system will provide full bandwidth frequency range
down to 60 Hz. The height of the array (number of cabinets)
will determine the total SPL available and how much low
frequency energy can be provided, proportional to the
upper-frequency spectrum.
If higher SPL is necessary, or the program content requires
additional low-frequency energy (e.g., the reinforcement
of popular music), then subwoofers should be used to
augment your MICA loudspeaker array(s).
Meyer Sound subwoofers, such as 700-HP, 600-HP and
650-P can achieve frequency response down to the 30 to
36 Hz range, extending the system response appreciably
and increasing the acoustic power of the system in the
lowest frequencies. The ideal ratio of MICA loudspeakers to
subwoofers depends on three factors:
■ Configuration of the array (number of elements and
angles)
■ Placement of the subwoofers — whether they are flown
or ground-stacked.
■ Frequency content of the signal being reproduced by
the system.
For most applications, two MICA loudspeakers for each
ground-stacked subwoofer yield good results in frequency
response and headroom. Using higher ratios (for example,
three MICA cabinets for one subwoofer) can have very
negative consequences, decreasing the headroom in the
low frequencies and exposing the drivers in the subwoofers
to excessive levels.
NOTE: The limit LEDs indicate when the safe
power level is exceeded. If the subwoofers
used in the system begin to limit before reaching the
required SPL at low frequencies, consider adding
more subwoofers to satisfy the SPL requirements
without exposing the drivers to excessive heat and/
or excursion — and eventual damage.
Using the filters in Galileo and LD-3 helps to easily integrate
and optimize your MICA arrays with subwoofers. The
use of high-pass filters may augment array headroom by
removing lower frequencies near the unit’s lower operating
range, while low-pass filters can remove unwanted mid-
low frequencies reproduced by the subwoofers. The use of
these filters reduces the area of overlap and minimizes the
interaction and possible cancellations between subsystems.
NOTE: Full-range signals may be applied to
Meyer Sound’s self-powered loudspeakers
and subwoofers because they have built-in active
crossovers. However, the use of external filters —
like the ones in the Galileo and LD-3 — is optional,
and should be used very carefully to minimize phase
shifts that can cause cancellations and deteriorate
the impulse response of the system.
Using MICA with the 700-HP Subwoofer
A MICA array can be deployed in combination with Meyer
Sound 700-HP subwoofers in applications where high SPL
is necessary, or the program content requires additional
low-frequency energy. For these applications the features of
the 700-HP are desirable — ultrahigh power and response
down to 30 Hz.
The 700-HP can be ground-stacked under a flown MICA
array or next to a MICA ground-stacked array. In addition,
the 700-HP subwoofers can be flown in a straight array next
to the MICA array using the optional MRK-700 rigging kit
and the MTG-700 top grid.
Table 5.1 shows how you can integrate MICA with 700-HP
using the Galileo and LD-3 filtering capabilities to fine-tune
the system. All data in Table 5.1 is based on designs with a
2:1 ratio and in a close-proximity, coplanar orientation.
NOTE: When loudspeakers and subwoofers
are physically separated by more than 4
feet — or delay must be used between them — a
measurement system such as SIM should be used
to determine the correct delay and polarity.
Table 5.1: MICA and 700-HP Subwoofer
HPF LPF
ø Reverse
Switch
Result
Off Off Engaged Boost in the 100 Hz region
80 80 Off Very flat response
NOTE: Because the 700-HP and the 650-P
subwoofers have identical phase in their
operating range, Table 5.1 also applies when using
the 650-P subwoofer (650-P set to pin 2 positive).
However, due to the higher output and headroom
of the 700-HP, when using the 650-P a lower
ratio must be used to achieve a similar system
headroom, e.g., three MICA with two 650-P.
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