
Meyer Sound Laboratories Inc M3D
™
Line Array
•
9
Two variable-speed primary fans run continuously with 
an inaudible operating noise of 22 dBA at 1 m at their 
slowest speed. The primary fans begin increasing speed 
when either of the two heatsinks reaches 42˚C. The fans 
reach full speed at 62˚C and are barely audible near the 
cabinet, even without an audio signal. In the event that 
the heatsink temperature reaches 74˚C, the secondary 
fans turn on and are clearly audible without an audio 
signal. The secondary fans turn on in response to:
■primary fan failure (check status immediately)
■high source levels for a prolonged period
■accumulation of dust along the cooling path
The secondary fans turn off when the temperature 
decreases to 68˚C.
USING AND REPLACING THE RAIN HOOD
The rain hood installed on the M3D user panel is provided 
to protect the loudspeaker’s electronics from direct 
exposure to rainfall. Before using the M3D, open the rain 
hood as described in the following procedure.
Opening the Rain Hood
1. Pull the exterior Velcro straps off the hood, allowing 
it to open. 
2. Lift the flap fully outward, and unfold the fabric rain 
hood. 
3. With your other hand, reach into the hood and free 
the two PVC supports from their corner pockets in the 
outer flap. 
4. Fold both supports out and reinsert them into the two 
pockets, shown in Figure 17, in the lower corners of 
the soft side flaps. This will hold the rain hood fully 
open for use, which is necessary for proper cooling of 
the M3D electronics.
See Figure 18 for an example of an installed rain hood.
NOTE:  In the highly unlikely event that the 
secondary fans do not keep the temperature 
below 85˚ C, the M3D automatically shuts down 
until AC power is removed and reapplied. If the 
M3D shuts down again after cooling and 
reapplying AC power, contact Meyer Sound for 
repair information.
Figure 17.  Rain hood stiffener pockets
Figure 18.  Fully open rain hood installed on a M3D
!CAUTION: Always be sure the rain hood is 
fully open when operating an M3D. Leaving the 
hood partially open will limit the airflow 
through the amplifier, which could cause it to 
overheat and shut down.
pocket 
1 ea. side
pocket
top stifener
FRONT