D-fend SA300 User Manual - page 10
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D-fend™ SA300 User Manual
each cabinet being an 8 ohm load rated at 800 watts. Note the output of the amplifier used to drive the subs, in this case
a bridged mono amplifier rated at 2000 watts into a 4 ohm load, is connected to the input of the SA300. The output of the
SA300 is connected to the two subwoofer cabinets that are daisy chained (connected in parallel). The load presented to
the SA300 will be a 4 ohm load rated at 1600 watts and the power amp will also see a 4 ohm load most of the time. We
will cover the programming of the SA300 to protect this system in the Advanced Programming section on page 17.
We chose to show this subwoofer system setup with two subs to show what the final load would be on the SA300. The
connection would be the same if one subwoofer cabinet was used and the rating of the one cabinet would be the load
applied to the SA300. In fact, using parallel, series, or parallel-series connection schemes, you could run multiple sub
cabinets off of a single SA300 unit, but the total load seen by the SA300 and power run through the SA300 must fall within
the ratings/guidelines given in the Maximum / Minimum Power Specifications on page 5.
Full System
In this section we show how to connect a typical live music system that includes top-boxes and subs for front of house
sound and floor wedges for the musicians on stage; see Figure 2.2 for our connection diagram. We will assume the Front
of House (FOH) is run bi-amped and in mono. We will also assume there is just one monitor mix, even though we show
three floor wedges. Since there will be three very different speaker-level signals (subwoofer, top-box, and monitor mix), we
will need to use three SA300’s to fully protect the system.
In this example system, the subwoofer is just one 4 ohm, 1600 watt box so the SA300 will see a 4 ohm, 1600 watt load
connected to its output. The amplifier used for the subwoofer system, a bridged mono 2000 watts @ 4 ohm unit, will be
connected to the input of the SA300. Actual programming of the SA300 will be covered in the Advanced Programming
section on page 17.
The two top-boxes are daisy chained (connected parallel), and since each one is an 8 ohm, 500 watt box, the SA300 used