Performance
Alpine conservatively states the frequency response to be 20Hz to 20kHz, but I measured it to be 5Hz to 32kHz at -1dB, very impressive for a Class D amplifier. In fact, the marketing guys at Alpine are not fond of the Class D moniker due its past limitations on frequency response and sound quality. This amplifier could pass for a really good A/B design, except that it is small and efficient.
The amplifier made rated power under all conditions and exceeded the number at 14.4V input. SNR was on the money, coming in at 100.8dBA on the bench (100dBA rated). Damping factor was 80, about right for this classification of amplifier, and the slew rate was a fairly average 7 volts per microsecond. There are op-amps in the signal section with better slew rate numbers than this, so why is it this low? The measurement involves putting a square wave through the amplifier and reading the slope on the oscilloscope. Because of the "rounding off" effect of the output filters, this number will generally be low on a Class D design. If the wave is sampled before the output filters, you would be reading the slope of the pwm, so it's difficult to come up with a meaningful number here. The best advice is to compare this number with other Class D amps.
The crossovers came in a little high on the frequency ranges, 37 to 387 instead of 30 to 300. This is most likely due to slight tolerances in the resistors, and is still quite useful in this range. The slopes were closer to 11dB/octave than 12dB, but they were well behaved. I engaged the over-current protection on many occasions, as well as the thermal protection a couple of times. Generally speaking, I abused this amp sufficiently to have great confidence in its reliability. There was never any turn-on or turn-off noise of any kind.
The owner's manual is one of those "Treasure Map" things, about the size of a small sheet but folded up into a 6" x 8" pack. The manual includes instructions in English, French and Spanish, with a set of pictures that explains how to mount and stack these amplifiers without even needing written instructions at all. While it's not an installation class by any means, if you have any experience with amplifier installation at all you will be OK with the instructions, once you find the set in the right language. There is a separate 6" x 8" sheet that explains the 1-year warranty and how to get the unit serviced.