What is wrong with a sub?


I often read that if you go with this...you'll need a sub.  Seems to me to get speakers where no subs are needed you pay 1.5 -> 2X the price of the "lessor" speakers with a sub.  I kinda like my sub.  Am I bush league (I may be, but I mean because of the sub)?
davidgwillett
Big-Greg hits the nail on the head. People say all the time “my speakers go down to xx hz, I don’t need a sub.” The truth is very few speakers, even larger floor standing speakers, are FLAT to 40 hz. Most have a bit of a midbass hump, which gives a bit of a peak in the 70-90hz range, which then allows a stated -6db point in the 30-40 hz range.

Even those speakers that can dig down into the 30hz range, have limited output and suffer from increase distortion in the bass frequencies. To be able to reproduce decent levels (i.e. 105 db) at 30hz and below in all but the smallest room, with reasonable distortion, takes at least 4 10” long throw drivers, two 12”, or 1 15” (all have approximately the same displacement). Go down to 8” drivers (assuming you can find decent sounding ones with an xmax of at least 15mm) you are up to 8 drivers. You can cheat it a bit with large vented enclosures, transmission lines, or folded horns, but do end up with tradeoffs in group delay.

Many will disagree about the above, but it is nearly always true.  Take the Revel Performa F228be, a wonderful, full range, $10,000 pair of floor standing speakers.  At 50hz, they are coming off their midbass peak to 0db.  At 30hz they are 5db down from flat, and 9 db down from their 80-100hz output.  Again, this is measured at lower volume levels, so no dynamic compression.  

https://www.stereophile.com/content/revel-performa-f228be-loudspeaker-measurements

$57,000 Wilsons, same thing:   https://www.stereophile.com/content/wilson-audio-specialties-alexia-series-2-loudspeaker-measurements


As Big-Greg says it isn’t about boom (which is 60-90 hz). It is the deep, almost inaudible bass, especially in live recordings, which give the sense of a real space. When dialed in properly, you hear no sub, just an increased dynamic range and music that has an amazing foundation.
My experience is that it is not uncommon that the optimal spot in a room for bass reproduction is different than the optimal spot for mid-range and treble.  Inclusion of one or two (depending on the room) subs, integrated properly with optimal placement, can deliver superior sound vs. a full range speaker.

I prefer stand mounts with subs vs. floor standing.  Personal preference and is reflected in the speakers I produce.  
The comments seem to be supporting what I thought.
Taking this to the $2,000-$25,000 speaker range for music that has lower bass in it, for the same about of cash...
Equivalent or better sound will likely come at a lower cost with speakers and a sub, than buying speakers alone.
AND
Many speakers build low range drivers in them, and buying the better mid-range speaker paired with a sub is likely a better value.  

FWIW I enjoy tube amps and lower power near field.  So I would not be buying a high watt SS amp to pair with some Maggie's which I'm told are great.  I had to choose between more expensive larger speakers with low range or going with a smaller speaker and good sub.  I did the latter, but am buying more stuff and wondering if I should change my thinking for a larger room.  I plan to do the same.  Good larger speakers, a sub to fill out the lower spots.  Music is Bach/classical (I don't hear the sub) and some pop/Fleetwood Mac kinda stuff where I certainly do.
davidgwillett,

You also need to keep in mind that part of the benefit comes from relieving the mains of the low frequency duties. This requires a crossover, preferably active, to limit the impact on the sound. Also, don’t go too small on the main speakers. I am a believer in Richard Vandersteen’s theory that your main speakers should be reasonably linear to one octave below the crossover frequency (so 40hz with an 80hz crossover). In the real world, your main speakers should have at least a couple of 5.25" drivers each or a 6.5" or larger to get proper integration.

And yes, the optimal position for speakers for best bass is usually different than the optimal position for imaging.  
@mcreyn - that was a bit Greek to me.  
What I have now:
300B SET (CAD-300SEI) with Watkins Gen 4 speakers on each side of my desk 8" high stands, REL i7(? small one) sub under desk to my left. 
The sub hooks to the amp speaker posts.  I'm pretty satisfied.

New amp is A/B 60W/channel and Vandersteen 2ci (which the SET amp can't push well).  This will go in a larger room with cinder block walls.  My plan is to get a larger REL sub and again hook to the speaker terminals.  I was also thinking Klipsh Forte instead.  Some of the Martin Logan looked good, but were pricey and had subs built in.  That kinda got me thinking why not separates (subs).