More Bass

@dadork 

Thanks for that information.  I won't be needing the Octobass as there is no musical signal down there.

You might try it on the 60s and 70s EMI LPs of recordings at the Kingsway Hall London, where the trains running on the subway below can be heard rumbling.  Some carts give a reasonable level signal that low; eg Ortofon claims 20Hz for the Anna at only -1.5dB (I wonder....).  If that's right there may be some output at 16Hz but you are getting very close to the resonance zone, so make sure you're no just listening to resonance.  Anyway, if it all works, you will get a very accurate impression of a subway train, if that's your bag. 

I'd give them more break-in time and make sure the speaker cables are in-phase. Even if the red and black ends of the speaker cables look like the correct + and - hook-up experiment and see if it makes a difference.

Sealed boxes can have tighter and faster bass and generally require more power, but you already have it, so no amp issue here. Four 10inch woofers is quite a lot of area to push air and your speakers should extend well below 30hz.

All is in the positioning, speaker or listening, and room space. Break in time can help but i would not expect to be the limiting factor.

I bet solving the above will get you there. It takes effort.

@navyachts Can you provide the dimensions of your room including ceiling height? I agree with others on the sealed vs ported design. Especially if the Signature SE have more than 3-4’ feet around them without walls, the 22Hz sealed will not charge the room as much as a ported speaker at 30Hz, let alone a quality sealed sub that goes down to 16-19Hz which is placed right in the corners. But it should provide detailed, accurate bass. I am now a Legacy Audio installer and have a pair of custom Signatures shipping soon. In my 19x23 room with 18’ slanted ceilings, I plan to use them 3-4’ from the front walls with subs in the corners. 

You want Bass.... Hook up a Mcintosh Ma6450 to your speakers. This amp has 4 times the bass I've ever heard on any other amp. When I use it, I have to turn the bass almost all the way down. You will never have to say I don't have enough bass again. Oh, I doubt that you would want to get a sub with it too.