Electronic cross-over on pre-amp out, to split signal to subwoofer and bookshelf speakers

I went with the Dayton Audio DSP-408, 4 RCA inputs, 8 outputs. Extreme flexibility in adjustments; x over, mixer, delay, and eq. I opted for the Bluetooth dongle, which allows adjustment at my listening position via an app. Or adjustment via laptop and USB. The x over has adjustment for high pass and low pass points, slopes up to 24db, polarity, and more. Eventually, I substituted the wall wart for a LPS with substantial improvement. 

Relieving the tube amps and the midbass drivers of the bottom octave or so should reduce distortion on both.  Those large frequencies hog a lot of power from the amps and cause large excursions to the midbass drivers.  If you can find out your amps input impedance, you could try a couple of inline filters (I used 10nF silver mica caps at a cost of < $20)

80hz-ish is a good option for two reasons...it keeps the sub playing in the range where it isn't directional, and it leaves just about the entire vocal range to the midbass driver. 

If you don't already have a sub, you might consider using two subs to help break up room nodes.   Most subs already have a built in low and high pass crossover, which could make it really simple to try.

I have been intrigued about the Sublime products for a while. If I were to buy tomorrow, it’s what I would choose. Good to hear feedback from someone who owns it. I get you have to buy crossover cards, but they’re inexpensive, like $12, could be fun to experiment.  And you get to stay in the analog environment.

I'm using a MiniDSP SHD as an electronic crossover and also using DIRAC.  Digital signals pass through to my Benchmark DAC3, and the sub signals go direct to my powered subs.  I come from the pro audio world, so using electronic crossovers/DSP is SOP.

I really like what I read.   You are all amazing!!!

My first test to establish baseline is to get cutover frequency and volume correct.  The speakers are flat from 100 Hz and up.  My room is pretty large about 15 by 30 feet.  With a 24 dB filter I am planning to start frequency setting very very low.  50 Hz.  Basically, sub contribution at 100 Hz will be gone and be "bookshelf" only.  I will use test tracks to get a sense of sound levels. 20, 30, 40, etc.  Make comparison with sub on and off.  Listen to digital recordings.  Get to a balances frequency and level.

I like the idea of filtering low frequency out early, post DAC.  Signal is already at a good level and get the low level out of pre and power.

Comments??