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If you鈥檙e looking for big bass on a small budget, the folks at Arc Audio have got just what you need in the form of their XDi1000.1 Class D amplifier. The XDi series of amps are designed to provide big power from a compact chassis, and at only $439 bucks (US), the price
is equally as compact.

Rated at 375, 650, and 1000 watts into 4, 2, and 1 ohm respectively, but measuring only 11.25鈥� x 6.5鈥� x 2.25鈥�, the powerful XDi1000.1 will fit into virtually any available space. The Arc Audio amp is nicely finished in a black anodized coating, with brushed aluminum accents providing nice contrast on the raised heatsink fins. Heavy duty power and speaker terminals are found on one end of the amp, with four gauge power connections, and a pair of dual paralleled speaker terminals that will easily accept eight gauge cable. The convenient dual speaker terminals provide easy wiring configurations for driving multiple woofers. Three 40A ATC fuses are also located on the 鈥渂usiness end鈥� of the amp, between the terminal blocks.

And while the XDi1000.1 may be modestly priced, it boasts features that are typically found on much more expensive products. Of course there is the usual gain and crossover controls (55-250Hz) but there is also a 10-50Hz subsonic filter, a variable phase control, and a bass boost EQ circuit with not only variable boost, but variable frequency (40-100Hz) as well! This parametric type EQ can be really handy during tuning of the subwoofer system to a specific vehicle or listeners taste. Plus, a wired remote control allows overall bass level control from the driver鈥檚 seat.

A look inside proves that the XDi is built for the long haul. The PCB is two layer glass epoxy 鈥淔R4鈥� material, and features surface mount very low tolerance parts. The power supply switching is handled by eight TO-220 case MOSFETs and two pair of large TO-247 case MOSFETs take care of the output. The power supply is fed energy via over 23,000碌F of capacitance, and the pout section uses another 8,800碌F of capacitance to store energy. All this power is constantly monitored by several different protection circuits, including protection from short circuits, over voltage, and over temperature. The blue 鈥減ower on鈥� LED will illuminate in red if any of the protection circuits become activated, so you鈥檒l always know what鈥檚 going on.

One of the best things about this type of amplifier, this one in particular, is excellent efficiency at 鈥渆veryday鈥� power levels. Sure, there are lots of amplifiers that profess to have better than 80% efficiency at full power. But the truth is, the vast majority of our listening is never done at full power. This is where a good design really stands out, when you look at overall efficiency at fractional power levels. What I鈥檓 talking about here, is how much power the amp consumes, when it鈥檚 only putting out 20, 50 or 100 wattswhere the majority of us do most of our listening. And this is where the Arc Audio XDi 1000.1 shines. This amplifier is over 80% efficient at 1/3 power levels, and draws less than 2 amps of current to produce 10 watts of power into 4 ohms. This means a much easier load on your charging system, plus a cooler running amplifier, because less power is lost to heat.

There are literally dozens of amplifiers available to drive your subwoofers. Some are very small, and take up minimal space. Some are very powerful, and can drive 1 ohm loads all day long. Some come with a full complement of signal adjustments and tuning functionality to help you tweak things exactly as you like them. And still others are simply very affordable, and offer good value.

The Arc Audio XDi1000.1 does all of the above, and there simply aren鈥檛 too many others that can make that claim.