You sound like you are personally modifying the AR9. You can add these drivers to most any speaker if you want to.

You also are not truly being realistic. To condemn speakers for not having enough bass is fine when money is no object but the reality is that good bass(not just a lot of it) costs a tremendous amount of money - for CURRENT loudspeakers. The trade-off is so obvious when you hear any big line of speakers the little Standmount is far faster sounding with the trade-off being that no a double bass and organ is not going to have justice done...though some will at least allude to the fact that it's there.

Trouble is A LOT of speakers that can do those Organ and double basses are slugs in the midrange and some have annoying metal tweeters that zing up and completely ruin violins. Directionality means a smaller sweetspot which is not the worst thing in the world...proper system set-up can fix that up.

Your assessment of SUbs is the same as my assessment...the best ones are the ones that are built specifically for the standmount like the Gershman Acoustics Sub 1 for the X1 and I suppose the Wilson Puppy for the Watt(never heard the combo).

If you're a big organ music fan then I can certainly see where you're coming from...you're going to need a considerable speaker - and if you're looking at the current speakers on the market - and let's be fair and compare STOCK speakers then what currently as a stock speaker would you buy.

The AR9 as a stoick speaker apparently had phase problems and was considered pretty average...you fixed them up.

But this does not help current buyers looking for speakers. Most view the Quads as best for classical music as stock speakers - The 63 to me is overpriced dynamically and bass void but they seem to be greatly loved and have lasted forever so maybe they're built for the small British apartments and strictly chamber and light ensemble stuff.