Frequently Asked Questions
The number of SRM loudspeakers that can be chained together at a time is limited only by the output
impedance of the mixer or equipment that is directly feeding them. To insure optimum signal transfer,
the net input impedance of a group of SRM 450 inputs (ZT) should be no less than 10 times the output
impedance of the equipment acting as the signal source. The net input impedance of a group of SRM
450’s can be found by donning a propeller-laden cap, and using the following simple formula: Where n
= the number of SRM 450’s being chained together and ZT = the total input impedance in Ohms of the
SRM 450 chain. For those of you with Mackie compact VLZ4 and PROFX mixers, this means that you can
chain up to sixteen SRM 450’s together without any problem; and if this isn’t loud enough, then you
should remove the earplugs before continuing.
How many SRM loudspeakers can be chained together using the Full Range/THRU jacks?
The presence of a 60Hz hum in the speaker only when a connection is made to another piece of equip-
ment suggests the presence of a ground loop. Such a loop is caused by electrical interaction of the
signal grounds on two pieces of equipment, and is not necessarily an indication of broken gear. If a bal-
anced connection to the SRM 1550 is being used, the simplest way to correct this problem is to lift the
signal ground on the end of the connecting cable closest to the signal source. NOTE: This is not to be
confused with disconnecting the safety ground on the power plug - this should be avoided at all costs,
as it can present a safety hazard. If an unbalanced connection is being made to the SRM 1550, a line
coupler such as the Ebtech Hum Eliminator can be used to eliminate the ground loop.
The speaker hums when I connect something to its input…
Peak power rating is 1200W, with RMS of 600W.
What is the power handling of the SRM 1550?
The volume control on the SRM 1550 subwoofer is actually an input sensitivity control. When set to half,
or Unity, it is not adding or subtracting any level from the source audio signal. Most sources such as a
mixer will have an output level that will work best with this control at unity. When turning it higher, you
are increasing the sensitivity of the SRM 1550’s inputs, and potentially overdriving the input. If the Limit
LED is blinking frequently or always on, you are driving the subwoofer too hard. Turn down the volume
control on the subwoofer, or at the source.
If the volume control is at half, does that mean I am only getting half power?
FAQ
