I'm having a hard time finding what exactly is different about the Rane and Ashly than a Marchand, Bryston, etc. I'm sure there are better quality parts, but they are all 24db/octave linkwitz-riley circuits.
I looked at the first watt, bryston, and JL, but the prices just don't make sense for a $3k sub. I'd rather have two F113s and a simple crossover than a bryston crossover and a single F113...
Do you really feel that the SVS would have a better HPF than a Rane or Ashly crossover? I'm doubtful that the crossover circuitry is any better and I'd suspect it to be worse.
And yeah, you're right, I don't want to go down the path of getting an AV pre-pro JUST for subwoofers. I want to keep things simple. I like the NAD, the DAC sounds great.
Also, I should mention that I run everything balanced and would like to keep it that way. It's one of the reasons I'm looking at the pro stuff, it's all balanced.
I'm almost thinking about getting the Ashly (I've ruled out the Rane because it has non-defeatable infrasonic and ultrasonic filters built in), as well as the miniDSP 2x4 and just trying out both. At the very least, I should get their microphone and use REW to see what the room looks like.
I'm learning there are two options. Get an analog crossover, which solves the crossover problem, has the least impact on the signal, but doesn't solve any other issues like room EQ, etc. OR, go with a digital crossover or DSP, potentially introduce some noise or character in the signal path, but can do a lot more than just a crossover.