Subwoofer xover settings for KEF LS50W (orig model)

Yes I did search and did not see much. I figures others have done this so I'd simply ask as see if anyoen has advice. The LS50W go quite a bit lower than the regular LS50s so I'm thinking of setting the low pass xover at maybe 50hz. But I can high pass as well thru the KEFs. So I figured I'd ask here what other have done with these active speakers in terms of a low and high pass settings. Looks like KEF defaults to just a low pass 80hz which seems high. 

Also I plan to use the sub settings via the KEP app but could obviously do much of this via the REL B1 sub as well. Thx
Over and over again agoners who do this say :

"Wow, when I switched from 40Hz to 80Hz I got so much more transparency and midrange clarity, it’s amazing. "

Plug your main speakers, if they are ported and raise the crossover frequency.
yep. I use 80Hz for my mid-fi (2 way bookshelves with 5 inch woofers....not LS50x) and it soounds pretty great at 80Hz. I sometimes cross at 100Hz but that sound quality is very dependent on the music...
Thx guys, 

Do you run the LS50W full range or set the KEF high pass close to where the low pass is set? 
Set the low and high pass filters the same then tweak to your taste.
i run all program to my sub which paasses everything above 80Hz to the bookshelf speakers which are run full range
Always high pass the speakers if possible. Once you high pass you can set the crossover anywhere you want and it will sound fine. 
A good spot is where the driver starts to take a dive and it would be crossed over to the next larger driver if there were one (in this case where the port pics up). The driver is down 5db by 70 hz on the ls50 but has flat output to 100. Somewhere between 70-100 is the right spot. Just have to see if how the quality of the sub is. I have large floor standing speakers with 8” drivers and cross over at 60z. I don’t here much difference going from 50-70 with a high pass.

With just a low pass it sounds pretty bad to me. Timing is off and it sounds best with the low pass just above my speakers lowest output (low passed at 40z and my speakers go to about 30hz) with a 24db roll off. 
Just a follow up. I set the high pass at 70hz and low pass at 60hz after much listening and measuring (test CD&SPL meter). The ls50w goes to lower frequencies than the passive ls50s. Confirmed with measurements. I had excess dB right around 60-70hz and ended up with the above settings to help best I could. Thx for the advice here. 
I hear 80 more than anything else and overlap the low and high settings because of the way the filters roll off instead of hitting a brick wall. 

good deal. How do you like the results? Happy with the sub as a whole? I am a big fan of subs and will probably never have a system without them. 
Do you know the slopes of the crossovers you use? 12 and 24db slopes need different overlap points. I am stuck with the single 24db for both low and high pass but it works out well for me as is. 
I'm just using the software DSP settings for the LS50W and I think they are 12db slopes but honestly not sure. I started and 80hz but to get more consistent SPLs I ended up with what I did. KEF does advocate playing with both as I did. There is a hump in the bass output of the LS50W down in that 65-75hz range in my room so this setup helped but could not eliminate that hump. 

It sounds pretty good especially once I dialed the phase in. The speakers by themselves do a much better job that I would have thought. I likely do not need a sub where I am using this but have it so wanted to experiment. It is a REL B1 so overkill for sure. I use this rig for TV 75% and music the other 25% of the time right now. The sub integration is pretty much seamless but also does not get pulled into duty too much as my main system is where I play loud music to keep the family happy. I move later this year all all this will change.
@jbs, go higher if you can. The Little woofers in the LS 50 carry the bulk of the midrange and unloading them will clean them up even further. I cross over with ESLs at 125 Hz. Try 100 Hz if you can. Roll off the LS50s a little earlier then you roll into the subwoofer say set the LS 50s to roll off at 110 Hz and set the subwoofer to 100 Hz. Also move the subwoofer so it is right against the wall between the LS50s then take the measurement from the front of the sub to your listening position and set the LS50s to exactly the same distance which should keep them off the wall a foot or two (on the radius of a circle).
The reason low crossover points are being recommended is because most sub manufacturers expect their clients to run the sub without a high pass filter on the main speakers. They are trying to bring the sub in under the main speakers. It is also much less noticeable way down and easier to integrate without screwing things up. You also have more flexibility in placement. But the improvement in distortion levels coming from the woofer more than make up for any disadvantage particularly with smaller loudspeakers that use the woofer as the principle midrange driver.
Your LS50s will grow to three times the size. 
Thx, the highest setting on the sub REL B1 is 95 hz. Yes, you read that right. That is where I have it now so the LS50W DSP settings do not interfere and I don't have two notches in play. I was trying to stay away from that area to keep it simple given this is a temp setup and goign way higher seemed problematic due to the sub xover. Maybe I'm all wrong about this. 

Normally I'd be running the sub at speaker level (unsing the differential hookup) but that'll wait until I put the REL with some other speakers and electronics.  
Download a sound level meter app like db on your smartphone, and stream some whitenoise (available on Spotify, elsewhere).

Then turn the sub level up and play with the crossover control. adjust level up and down until flattest in the bass region. That will give you a reasonable estimate of where your exact level and crossover settings should be. Adjust phase if available for best impact from percussion, etc. then fine tune level and xover settings from there as needed.

You might be surprised what you find this way compared to doing it by ear alone. Probably more good sound out of your sub than expected.

I had original ls50s crossed over at ~ 60-80 hz. WIth new metas, I ended up with crossover on same sub set at lowest point ~ 40 hz and higher levels than prior. Everything sounds fuller and more alive now, and just the right amount of bass on all recordings. Room is 12X12’ square which many will say is horrible for bass, but fact is it sounds really good. BEst bass I have had ever.  Sub is Klipsch sw-308, a little 8" dynamo.
Mapman, Yes this is exactly what I did :) Stereophile test CD (bass tones) and the "vintage" Radio Shack SPL meter. I start and make changes based on that and at the end dial in by ear.  

I'm sure the Metas are nice and someday I'll probably own a pair. I got these Ws to try out and admit I am super impressed. The wireless capability really makes them so easy to put anywhere and use in a variety of ways. Quite a powerful and simple device all in. Thx