Performance
The frequency response starts at 4Hz and goes to 23kHz where it runs into a "brick wall" filter, which is easy to do in DSP-land and impossible in the normal world. All of the frequency measurements show up on my tests just like they appear in the controller window of the Zapco software. It's just math, after all, but there are no programming glitches. All the crossovers and EQs do what they are designed to do.
The owner's manual states the power ratings for this amplifier as 4 x 50 watts plus 2 x 100 watts at 4 ohms, but I think that's a typographical error. The rail voltages for all six channels are the same, so it doesn't make sense that two channels would be higher at the same impedance. Channels five and six were designed for more current and will certainly do the 2 x 100 at 2 ohms, but I'm going to go with 6 x 50 watts at 4 ohms. The amp made rated power even at 12.5-volt input, and the SNR and damping factor were just a tad under the factory rating. Measured SNR was 94dB, spec is 95dB; calculated damping factor was 141 instead of the rated 160 at 4 ohms. There was no noise on turn-on or turn-off, and none was detected when the amp was on.
The owner's manual is a 68-page book, but don't worry, it covers eight different amplifiers. The hard part is finding the page with your amp on it. It is very informative, covering all of the amplifier features and giving you some system diagrams to choose from as well. The manual itself did not contain a warranty statement, but there are instructions for returning the unit if it needs repair.
Listening Test
I installed the amplifier in the trunk of the Buick, using six of the eight outputs from the Alpine Media Controller to feed all three SymbiLink inputs on the DC650.6. Channels one through four drive the front separates and rear 6x9s, and I bridged five and six to my 12" DVC Viper subwoofer. I ran the Alpine through its time correction and road EQ setup to make sure this amp would be set up the same as all the others and started listening. I always start with the boring sound quality stuff first, so bear with me. (If I started with Bass Mekanik, I wouldn't be able to hear any sound quality!) First track was "Mary" from DADA's Puzzle album. The song starts with a rich acoustic guitar ditty and two male vocals, a lead and a harmony. The guitar sounded really good, almost to the point of being able to identify the undersaddle pickup, which sounds like a Fishman to me. (No, not the Fish Man. Oh, never mind.) The vocals came in very well, centered and distinct. It was a real treat when the drums and bass kicked in because I had it way too loud!
I use a Michael Ruff track, "Eyes of Love," to see how good the midbass response is. On this particular track, the drums and bass are intolerably muddy if the midbass is too strong, but they just disappear if the midbass is soft. It has to be right to reproduce this tune well, and the Zapco setup was in the zone. Maybe a tad indistinct, but it passed the test. Next I chose a little Bonnie Raitt to check the female vocals, which seemed a little distant. I put in Donald Fagen's Kamakiriad and played the intros of "Snowbound" and "Tomorrow's Girls." Wow--tight, solid bass and great cymbals. It was as good as I've heard in awhile. All through these tracks, I was pushing the subwoofer level a little higher every time. I finally gave in, popped in Bass Mekanik and sampled most of the tracks with the subwoofer level pegged on the Alpine head unit. There was a little problem here--lots of noise up front. It seems I neglected to set the highpass on the separates and they were screaming for mercy. I stopped and added a 24dB highpass to the fronts (same on the rears) to match the 24dB lowpass on the subs. That did the trick. I briefly revisited "Eyes of Love" and a couple of Bonnie Raitt tunes. Sure enough, Bonnie's voice was back up front in the mix and the midbass, perfect on "Eyes."
Back to "Sine Bombs" on Bass Mekanik--what a window rattler! Everything in my car was moving and the neighbors came out to check what was going on. I went out back to watch the subwoofer jumping for a minute and noticed that the input clip lights were blinking a little and so were the output clip lights, ever so slightly. When both are blinking at about the same time, I know I've got the amp set correctly so I can get every bit of clean power out of it.
Conclusion
I am very impressed by this amplifier. It has the sound quality and balls that Zapco is renowned for, but the DSP is a generation beyond anything else to date. It just does so much! Granted, not everyone will fiddle with it from a laptop, but what else do you need? Compression, Dolby Digital? It's a matter of writing the software, dude. At a retail price of $1,189 and total 775 watts at 1%THD, the magic watts/dollar ratio is $1.53 per watt. That's up in the higher sound quality range, but about right for the performance of this amplifier. If you add the DRC-SL at $240, the number goes up to $1.84, but where can you buy the processing power built into this amp for $240? I don't think you can, and most consumers won't need the DRC-SL. Have your Zapco shop install it and make all the adjustments, and you're enjoying the benefits without paying to access the processor constantly. I think this is a great value for both the high-end enthusiast and the constant tinkerer. v