Sabrina X Anyone Add Subwoofer(s)

Let your dealer guide you.  If you're using a reputable Wilson dealer they will tell you what you need.  But what's the hurry? Are they giving you a discount if you buy them together?  Try without first.  You might be pleasantly surprised.

The first thing is to work out what the problem is. I have a quite small listening room 4.5 x 3.2 metres. Bass control is my issue not lack of bass, the walls shake and items on walls rattle even at moderate volumes. Adding 2 subwoofers has allowed me to even out the bass response whilst using a miniDSP to correct for room modes. The difference is startling. It also enables be to restrict the bass output of my tube hybrid power amp. This works in class A up to 10 watts, removing bass from the amp and speakers below 60Hz means I'm always in class A. 

I think well integrated subs improve most any speaker. A few exceptions for sure. But as others have suggested might be best to get them in your house and see what you think and go from there.

If you are considering spending $5k on a sub that suggests that you could have afforded the Yvette that has a 10" woofer that goes down to 20hz. With the right amplifier probably solid state power, that drives a difficult load 86db and 4ohms, I would hope if you can't get enough bass out of them then there is something fundamentally wrong.

If you are considering spending $5k on a sub that suggests that you could have afforded the Yvette that has a 10" woofer that goes down to 20hz. With the right amplifier probably solid state power, that drives a difficult load 86db and 4ohms, I would hope if you can't get enough bass out of them then there is something fundamentally wrong.

No.  Subs are much more than just getting “enough bass,” and your statement indicates you’ve never heard a good system with properly integrated subs.  Too bad because there’s much more to it than just more bass.  I’d take the Sabrina X and two good subs over the Yvette any day.  Once you hear what subs can add to a system you won’t go back to listening without them.