Active line level crossover with subwoofer out - HELP


Hi.

Helping my friend with another challenge. 
Looking for a line level crossover. His preamp does not have a subwoofer out.

What he wants to do is have a high pass filter between the preamp and his power amp. This so his Spendor BC1’s are spared anything below 40 or 50hz. And, the crossover needs a low pass filter to spare the subwoofer the high frequencies. 
Thoughts? 
Thanks!
perkri
I have to say last show I was at, the Vandersteen room was the best sounding. The compensation for the room worked really well.
PS - I do like the Mytek products, but for the most part I’m not fanatical about them.  They have class-leading specs AND sound really good but over the last 10-15 years a lot of great sounding DACs have hit the market.

The only DAC I’m really against are the standalone Oppo lines. I made one or two bad comments about them on Audiogon about them, and the company went under. ;-)

Now I am become Death, the destroyer of worlds.

Fear me, mortals!!!
Also, no matter the route you go ruler flat rarely sounds best - especially in the analog domain.

my favorite analog EQ is the one Roger Modjeski designed for Beveridge .... sweet sounding.. I think Music Reference might still have one or three...
And finally cut is your friend, boost can really ripple... on a well thought out analog EQ cut is 2x boost....
Also, no matter the route you go ruler flat rarely sounds best - especially in the analog domain.

Indeed, you, Fred Toole and I agree on this. Fixing gross abnormalities in the bass region is often all you should do.