What percentage of audiophiles use a sub ?

Two useful scenarios I see for using a powered sub:

1) handle the low end with smaller monitor speakers that do not do much below 50 hz or so.

2) provide greater flexibility for dealing with room acoustics and how that affects the low end in particular. Subs might be used to cover frequencies that full range speakers are capable of handling otherwise in this case in order to be able to fine tune the bass easier than dealing with alternate speaker placement, alternate equipment, room treatments, etc. Fewer subs are well suited for this scenario in that they must perform well at the lowest frequencies in order to add value over good full range speakers

Yes, also true that offloading bass to a separate powered sub provides potential for full range speakers to perform better in remaining range covered in many cases due to less demand on the speakers to cover a wider range and benefits now to amplifier driving the speaker now over a more limited range as well.

Most every speaker I know of suffers in imaging, transparency, sound stage and overall clarity when closer to a wall.

Its true that an advantage of a separate sub or two is that the speakers can now be farther away from walls where most everything except bass performance often benefits.

I don't understand any dogma that says subs are inconsistent with two channel stereo reproduction. That makes no sense to me at all.

I Dynaudio monitors that do a fantastic job with an extended low end for their size.

Set up properly, they almost do it all but small speakers cannot move enough air to deliver a muscular low end as larger full range designs can. So I have to say they almost do it all, but do require a sub to really do it all to the extent of good full designs. All smaller monitors I have ever heard do, even Magico Minis.

For many, they do it all enough that it does not matter which is fine, but I have yet to hear small monitors that can compete with equally good full range speakers for delivering the oomph that some music requires.

Tigger,

I will just add that I do think adding a well matched powered sub or two to monitors is quite capable of doing it all well and often at considerably lower cost than most single box full range speakers combined with similar suited amplification needed to match a powered sub.

Plus from the perspective of setup flexibility and convenience, a separate powered sub for the low end helps a lot. Proper setup in the room is key to performance. Often there are things that prevent people from accomplishing optimal setup with big massive single box speakers in many situations. They are just too heavy to move or experiment with easily so people do not bother as much or the placement options within the room is just too limited to get it all right including the low end. When this is the case, there is a very strong case to be made for offloading the bass performance to a dedicated device (a sub) designed to handle only that.

Also, yes, good monitors (and also perhaps a good set of headphones) are often just what the doctor ordered for apartment dwellers.

" if you really did your homework"

That's always the key.

You might get lucky and stumble into a good thing but don't bet on it.