SabrinaX Sub-Crossover

First time posting. I recently got a new pair of SabrinaX speakers and paired them with two Martin Logan 1100x subs. The system together sounds incredible. The SabrinaX is rated down to 31Hz. Where should I cross-over the subs? I did it at 35Hz with a steep roll-off (4th order) but wondering if people with more knowledge have any recommendations? 



My advice above assumes you will be using a high pass filter on the mains, if not, you’ll need to still seal your ports, and then use measurements to figure out the best integration point which will probably be around 40 to 60 Hz.

Undoubtedly someone will get huffy about my recommendation about sealing a speaker which is ported.  I say it as a speaker builder, and remind you that the procedure is easily reversible, depending on the condition of your socks.

Since the topic of a high pass filter has been mentioned I figured I’d share this, as it may be of interest to some - particularly Ayre Acoustics owners. I own an Ayre VX-5 Twenty amp. For that amp, and a few other Ayre units, a replacement "high pass input board" is available. Ayre makes a tweak to capacitors on the board to provide a high pass at 100Hz at the amplifier input. So the amp can feed the mains at 100Hz high pass, and the other output on my Ayre KX-5 Twenty preamp can feed a pair of subs. Evidently it’s common for Vandersteen owners using Ayre equipment. I’m getting to know a pair of Wilson Audio Duette with a pair of subs and I have a pair of these boards. I haven’t used them yet, but I expect they will be very handy - especially since I very much like 2-way speakers paired with subs to dial in the low end. I should be able to play with any 2 way speaker and should get a nice benefit from taking stress off the amp, and the woofer of the 2-way. The fact of the matter is, the Wilson Duette sound so good without the high pass filters I haven’t been in a rush to install them!

Thanks so much for all the great advice! 

I forgot to mention that I am driving them with a McIntosh MA8950. 

They are plus or minus 3 db at 31 hz. Ask Wilson what order the speaker is 

2 nd or 4 th and stick with that   Go around 37-38 hz. You never want overlap 

at least 6 db higher for your specs are not flat at 31 hz try 73 hz kthey 38 

on. A bunch of music , btw the Martin logan subs are not in the same league 

a Svs 4000, or ultra 16 much better controlled ,the JL audio Fathom are the best of the bunch ,sealed are always more accurate then vented or passive radiator .

the ML subs are decent ,I am just speaking in absolute terms.

Thanks audioman!

Unfortunately, my budget is exhausted after the McIntosh and Sabrina's so the subs are a carryover from my prior system. The remaining $$$ is for proper cables. Frankly, the way the room acoustics are optimized when the Wilson dealer was setting the Sabrina's up they were tricked into thinking the subs were on when they weren't.