Performance
The 2000D was able to beat its 4-ohm power rating by several watts and our 2- and 1-ohm measurements show “close enough” figures of 822 watts and 1124 watts, respectively. When driving 1-ohm loads, the 2000D exceeds 1% THD+N well before the amp begins to clip. Our 14-volt spec of 1124 watts is at about 1.5% THD+N while the actual 1% spec would fall somewhere around 600 watts. The vast majority of subwoofer systems are well past 1% THD+N when driven in this power range, so this isn’t exactly a major shortcoming. The 2000D showed little problem driving our reactive loads, providing essentially the same output into either reactive or resistive loads of the same nominal impedance.

Efficiency at 1/3 maximum power measured 65 percent. If you drive an amplifier to its full undistorted output with the peaks of well recorded music, measure the output and average it over time, you’ll get something that’s pretty close to one third of the amps full undistorted output. This is a particularly inefficient power range in most amps, but it’s also the range that the amp spends the most time in during normal operation. To complicate the matter further, we perform this test into the amp’s lowest rated impedance, in this case, 1-ohm. All of the “1-ohm stable” class D amps that we’ve tested, including the 2000D, are well past the optimum efficiency envelope when driving 1-ohm loads. If an amp fails to double its output when the load impedance is halved, the efficiency also drops. Since the class D craze began, we’ve seen a 70 percent, a 74 percent, and a whole bunch of 65 percent. Interestingly enough, neither of the amps that were in the 70’s carried a 1-ohm rating.

Connections & Adjustments
Connections to the 2000D include line-level RCA inputs and outputs, telephone-style remote connector, and captive-type terminal blocks for all power and speaker connections. Power and ground connections accept up to 4-guage while speaker connections accept up to 8-guage. Adjustments include input sensitivity, crossover cutoff frequency (3rd order, variable from 36 Hz to 280 Hz), subsonic filter (3rd order, variable from 10 Hz to 34 Hz), bass boost center frequency (variable from 36 Hz to 151 Hz), and bass boost level (variable from 0 to +12 dB with local amplifier control or 0 to +20 dB with the remote).

Installation
Installing the 2000D should be relatively hassle-free. All of the necessary hardware, including hex wrenches for the power and speaker connections, is included. The amp measures 10.5 x 12.2 x 2.6 inches, which is just a bit taller than average, but is still probably sufficient for most under-seat applications.

The 2000D’s cooling fan is not temperature controlled, so if the amp is on, it’s running. In a trunk installation, this won’t be a consideration, but in a very quiet passenger compartment install, a real geek might just hear that fan. There is one other fan characteristic that’s a little weird but, on this point, I don’t want to pick on the 2000D exclusively. It seems that every fan that I’ve ever seen in a car audio amplifier blows the wrong way. If heat rises, why do all of the fans blow downward? If you’re looking for an amp, I wouldn’t lose much sleep over this subject, especially since everyone seems to do it the same way. However, it seems a little odd to try to fight the laws of convection.

A variable subsonic filter is always a welcome addition to a powerful sub amp, but my favorite extra bell/whistle on this unit is the adjustable center frequency on the bass boost circuit. In a perfect world, I’d just leave the amp flat and use a really good EQ to do the tuning, but if you’re going to try to tweak the bottom end via bass boost, there seems to be three available choices: 1. Switchable — this type introduces a fixed amount of boost at a fixed frequency and is practically useless; 2. Variable (most common) — this type allows a variable amount of boost at a fixed frequency and is only marginally more useful than type 1; 3. Variable Boost & Frequency — this type allows you to control both how much boost and where it occurs within the amps frequency range. This is a major step in the right direction; elevating bass boost from just another amp selling feature to something that approaches real tool status. The addition of a bandwidth (Q) adjustment and the ability to either boost or cut would put it over the top, providing full parametric operation. However, fine-tuning a system with the controls on an amplifier can be a tedious chore, especially if the amp’s installed in the trunk and the remote only controls one function.