Hello 2pyop,
I think a better question is why would anyone expect 2 full-range floor standing speakers, no matter their quality or price, to be able to provide both good bass response and good midrange/treble response at a designated listening seat when the low frequency sections of the speakers are not able to be independently positioned in the room. This makes as little sense to me as the use of subs apparently does to you.
It’s well known that bass soundwaves behave very differently in any given room than midrange/treble soundwaves will behave in the same room, mainly due to physics. The frequency of soundwaves are directly related to their length, the lower the frequency the longer the sound wave. This equates to a 20 Hz deep bass soundwave being 56 feet long and a 20,000 Hz treble soundwave being .056 inches long.
Humans are very adept at determining the originating location of midrange/treble frequencies but very poor at determining the originating location of bass frequencies at or below about 80 Hz. In other words, midrange/treble frequencies are very directional and deep bass frequencies are not.
All soundwaves, once launched, continue to move forward and bounce or reflect off any room boundaries (floor, ceiling, walls) they encounter along the way until they run out of energy. This regularly results in direct and reflected soundwaves meeting/colliding which causes frequencies to be perceived at these spots (called room modes) in the room to be exaggerated, attenuated or even cancelled.
Midrange/treble room modes are generally perceived as a sense of ’airiness’ and ’liveliness’ and the modes can be significantly reduced in any room via room treatment panels. Bass room modes are generally perceived as a sense that the bass is not smooth and natural and the modes can only be reduced, according to traditional thinking, via expensive and large bass trap room treatments.
There is another proven alternative method, however, that takes a very different approach called a distributed bass array (dba) that utilizes the principles of psycho acoustics to provide excellent perceived bass response throughout the entire room, not just at a single dedicated sweet spot. These complete dba systems can be purchased for $2,800 from Audio Kinesis as either the Swarm or Debra system. The main difference being the Swarm subs are a bit shorter and wider than the Debra subs.
Both systems include four 4 ohm subs with 10" aluminum long-throw drivers and a single class AB 1K watt amp that drives all 4 subs. The subs are strategically distributed within the room and their purpose is to create many bass modes (peaks, dips and nulls) in the room with the knowledge that our brains will process these numerous varying modes by averaging them out.
I’ve used the AK Debra dba system for about 4 years now. This concept works like a charm and provides bass that is very accurate, natural, detailed and smooth throughout my entire 23 x 16 x 8 foot room. It provides what I consider sota bass performance that is able to reproduce whatever bass the content calls for; rhythmic, taut and detailed bass for music as well as sudden, deep and powerful bass for ht and music. Here’s a review from the Absolute Sound on the A K Swarm system:
www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/Tim