SDX-400.1

The SDX-400.1 is a water-resistant Class D monoblock built to add bass to vehicles that get wet. It produces 400W x 1 at 1 ohm, 300W x 1 at 2 ohms, and 175W x 1 at 4 ohms, from a chassis measuring 5.75 by 4 by 2.125 inches.

That size is the reason to buy it. A compact footprint means it mounts under a UTV seat, inside a center console, behind a boat dash, or in a motorcycle bag where a full-size monoblock simply will not go. The heavy cast aluminum casing sheds heat and shields the electronics, and the audio controls sit beneath a sealed, removable cover so rain, dust, and spray stay out of the pots. Unscrew the badge with an allen key when you need to adjust.

A variable low pass filter covering 50 Hz to 250 Hz sets the crossover to your speakers, and variable bass boost lets you add weight to the low end. Signal to noise ratio is 90 dB. DC auto-sensing turn on removes the need for a remote turn-on wire, which keeps a powersports install simple.

Protection circuitry covers thermal, voltage, speaker short, and DC-offset conditions. A wired remote control is included, so bass level is adjustable from the seat without opening the control cover.

Operating voltage is 11.5V to 15V with a 40A recommended fuse, so a modest power wire and existing charging system usually handle it.