Thanks Jax2 and Lissnr.
I will try this.
I will try this.
Until recently I was running a Sonata 2 with my Rel Stadium 2. Jax has good points, settings will be different with these slightly different models (The Sonata 2 used 2 x 10"s) as well as your room but you should get a SPL meter to help. By ear, in my particular room I found myself keeping the crossover quite low. I can't recall the exact numbers but I think I was only up about "1 click" on the coarse setting and possibly only 1 ( or 2 max) additional "click(s)" on the fine setting (at most). I always kept the gain quite low too... barely between the 9 o'clock and never much, if any, more than the 10 o'clock position. This was never overly noticeable on most music... on the occasionally very deep bass notes I felt there was a little extra help on filling out the lowest extension but it was always very subtle and well integrated. My emphasis was on what it did for locking in the image focus of the performers, especially the center image of a solo singer... the Rel, when applied as described, added that last bit of extra image definition in an absolutely uncanny way. My tip is to err on less is more...put on a track with some good low bass extension that has vocals too, when you can start to hear a plummy ripeness, you've definitely gone too far, back off until that's gone but your singer materializes more profoundly... there is a balance there you can find with experimentation. Be patient. Good luck.
I have a pair of Sonatinas that I use an ACI Force XL sub with. Integration in my room was a bit tricky. I'd highly recommend using an SPL meter and a test tone sampler disc to aid you in the process. Obviously the different speakers, different room and different sub is not going to provide very useful info for you. FWIW I ended up crossing over at around 65hz running the speakers full range. I tried a low frequency cutoff at around the same frequency, but preferred the extra fullness that running the speakers full range provided. I'm using line level inputs from the pre to the sub. Also, though my Sonatinas are spec'd just a bit higher in the low end (I seem to recall around 27hz perhaps) than your Sonata III's they do not measure remotely close to that low figure in my room. Instead they drop off fairly steeply at around 40hz. You may find the more accurate in-room response for your Sonatas using an SPL meter (relatively inexpensive from Radio Shack). You can also easily adjust for phase using the same meter, as well as find the best position in your room with an assistant. Before I used the meter I was having a devil of a time trying to set up the sub so it wasn't either too pronounced or seemingly doing nothing at all. I think most folks err on the pronounced side. For music I'd say the goal was closer to an 'invisible' presence, as it were.