Subwoofer for classical music listener

RV, that sounds like either you spoke with a very confused rep, or there was a miscommunication. The high passed line-level outputs of the sub would have no way of knowing whether they are connected to a speaker having a built-in amplifier, or to an amplifier that in turn is connected to a passive speaker.

You would simply connect the preamp outputs to the sub’s line-level inputs, and connect the sub’s high passed line-level outputs (left and right) to the inputs of your left and right monoblock amplifiers, respectively. You would probably then want to set the sub’s internal low pass filter to the vicinity of 80 Hz (and then fine tune by ear), since the high pass function has a fixed setting of 80 Hz.

An uncertainty pertaining to how good the resulting sonics would be, though, is introduced by the fact that the output impedance of the sub’s line-level outputs does not appear to be specified. Although I wouldn’t be surprised if that proved not to be an issue with the 22K input impedance of your amps.

Best regards,
-- Al

That's what I thought!  I can't understand why he would have told me that.  Maybe it's because it was closing time on aFriday and he didn't want to be bothered transacting a cable sale.  Who Knows?!

I found a lot of SVS' advice questionable. I went with Rythmik instead.

For what it’s worth, I don’t like running my main speakers through some external crossover. I am concerned that additional electronics in the way of the main speakers will cause a loss of transparency. I let them play full range, and feed the subs by a second set of outputs on my line stage, directly to the amps on a pair of 15 inch sealed Rythmiks. I haven’t had the room measured yet, but I got them playing pretty good without muddling up the mid bass; you almost don’t know they are there, except for added bass punch when it is on the recording; even when there is no low bass in the program material, the subs seem to add air and dimensionality in the lower octaves which, surprisingly, improves the midrange as well. And I’m crossing over really low- the subs are set to start rolling off at 50hz at a fairly steep curve- 24db. Not shilling for Rythmik, but this is the second transaction I’ve had with Brian and he’s very good. My subs do not have a speaker level connection, i.e. taking the signal from your main amp to feed the subs, to lend the character of the main amp to the sub amp for increased coherence. That’s how the integrated woofers in my Avantgarde’s are set up, which benefit from the extra punch and depth of these "external" subs. I’m also messing with cheap DSP on the subs, which does make some improvements but I think getting the subs located optimally, with a minimum of room treatment and processing is the first step and getting measurements is essential for that. I do have bass traps in all 4 corners and the room sounds pretty good. Once I’ve got that sorted, and it may involve some additional room treatment, repositioning, and possibly some EQ, I’ll be cooking. I’ve only had the system up and running for a couple weeks now since I moved from the NE, and continue to dial it in. Those Blue Jeans woofer cables are OK, and cheap. I use fancy cable elsewhere in the system and it all plays together pretty nicely. I’m sure I’ll tweak and improve it more as time goes on but that’s part of the fun, so long as it doesn’t interfere with your ability to enjoy what you have.