What is "slope"???

I dont think I totally understand the properties of slope?

I'm setting up a Theta Casablanca and when it comes to crossover I get it,....but as far as setting the slope, Im at a loss as to what it addresses.

Please help me understand what I should be listening for.

OK, so the second part of my question was..

What should I be listening for to establish the proper slope for my processor?

Please be as straight forward as possible.

Thanks for the help!
M, is this a high- or low-pass filter? Do you have large, full-range speakers or ones with relatively limited bass output? Do the main speakers have plenty of power-handling capability full range or can you overdrive them at YOUR normal, high listening levels?
My speakers are full range Thiel 2.3's. They are capable of full range bass, but I cross them over at 80Hz to my sub. I find it allows the Thiels to do what they do best.

The slope options available are 6db, 12db, 18db and 24db

Hope this helps.
Does the Casablanca give you the choice of sending the full signal to the subwoofer channels (i.e. SLOPE OFF)? If so, then why not set the subs to receive the full signal and let the sub's filter let in what it needs.

But if you want to bypass the Thiels completely, start with the 80 hz frequency at 24 db. This steep roll off may result in a "hole" at 80 hz. Keep going down the slope decade until the sound is coherent, that is, the sound levels at that frequency are similar between the sub and the speakers. Ideally, they should be within 3db at 60,80 and 100 hz but not more than 6 db. A sound pressure level meter will greatly help. The bass should sound fast and quickly disappear - not resonating or reverberating.

If you go to 6 db, then the speaker woofer may overrun the sub and you'll get reinforcement (louder, bass boom, fat bass, etc.) at that frequency. Sorry, but this is probably a trial and error process. Also note that the Thiels have a 6 db slope - but that is with its own drivers and will probably not work so great with a sub at that slope setting.

BTW - make sure your speakers are properly set up before trying out the different slopes or you may not notice a difference.
So you're talking about the high-pass filter to the Thiels?

If so, my 1st response is 'why bother'? Using any of these filters introduces phase errors into the bass and midrange frequencies. Also, it sounds as if you're using one subwoof, so filtering the bass from the Thiels makes the low- and midbass mono instead of stereo.

My 2nd response is the less 'slope' (and phase errors) the better. If you feel you MUST use a hi-pass filter, use as gentle a one as you can select.

But try running them fullrange and filling just the bottom octave with the subwoof.