More Bass

@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.

Those speakers are not short on bass.  Could be a room issue but more likely it is your personal taste, which I am not criticizing.  My point is you want more bass than all speakers  will provide.

Easier than a sub is an equalizer and that speaker has the horsepower to give you what you want.

Jerry

This thread is so long because of the lack of measurements.  I strongly recommend you get OmniMic or Room EQ Wizard and measure at your listening location.

Yes, the lack of room treatment can make the room sound far too bright, but it can also have bad room modes.

Look at the AM Acoustics room mode simulator and try to keep your speakers and listening chair out of the lowest modes.

I think I’ve found your culprit. These speakers have about 2 Ohms for most of the bass region. A 4 Ohm rating is significantly optimistic.

They will require strong amplifiers capable of driving such difficult loads.