My argument for towers with dual or triple 8" or smaller woofers not allowing for sufficient bass is highlighted in this paragraph about the 901's:
Another aspect to the Bose 301/501/701/901 series is their use of multiple small speaker elements for reproducing bass. While most speakers use just one large high-quality expensive element for the bass frequencies, Bose speakers such as the 901s use many smaller lower-quality less-expensive speaker elements, wired together with complex equalization circuitry. While this certainly produces bass, many people feel that the deep bass is attenuated, and that whatever bass there is contains large amounts of distortion. Others apparently believe the bass is deep and of high-quality. Whichever way your opinions run, it should be noted that there are well-established theories about the size of the driver versus its lower frequency limit --- the bigger the driver the lower the frequencies it can naturally reproduce --- which Bose violates, or at least tries to circumvent in a highly debatable fashion. More specifically, John Busenitz says:
"When judging low frequency response, it is not only the total surface area that is important, but the excursion capability of the drivers and their resonance frequency, which determines the low frequency cutoff. Smaller drivers almost always have far less excursion capability and higher resonances than larger drivers. That is why Bose is pretty much alone in using multiple small drivers."
Just about all of todays modern speakers require a separate subwoofer to reproduce the bass that is lost to the larger 12" and 15" woofers in the front speakers that have evaporated from the market. 901's may play loud, and with several 33 band Soundcraftsman eq's, may sound pretty decent, they still lack the bass necessary to knock your mother n laws picture off the wall.
