Does full range guarantee bass?

By definition, full-range does guarantee you bass. However, not all full-range speakers will do it the same or even well.

IMO, Full range should be around 20Hz to 20+ kHz. And therefore, should guarantee bass. Quality of bass is another story.

There is much musical info at the 22Hz to 40Hz range almost regardless of music preference. And yes the amp plays as big a part as the woofer itself. If either the amp or the woofer come up short, ill-defined bass is the result.

Perhaps Vandersteen suggests full range speakers in order to allow their subwoofer to focus on the lowest bass regions leaving the speakers to concentrate on the bass and mid-bass regions.

Full range should always give full range however good or bad it does that.

However, without getting into specifics, in order to obtain the best of full range, one must seek out the best quality recordings, speakers, cables, front-end source, preamp, amp, room acoustics, and proper handling of air-borne vibrations by the equipment (cones, spikes, rubber footers, etc.) and rack/stands.

Not to mention the synergy of all the above.

And price usually has little to with achieving that level of quality. Although sometimes it helps expedite the process or quest.

-IMO

Full range is acheivable only in combination of both amplification and speaker.
Theoretically even small radio speaker can go to 40Hz but what you should know is levels i.e. a relative amplitude in dB how loud can you hear it.

Equipment cannot gaurantee sub-50Hz bass. The key determinate of high quality deep bass is the interaction between your room and your speakers. Speaker/listener positioning is critical as well as appropriate equipment isolation from feedback. Somewhat paradoxically, subwoofers work best with those speakers that need them least. I take the position that subwoofers shouldn't be used to provide bass, but are only appropriate for deep bass (sub 40Hz) augmentation. REL subwoofers are a good embodiment of this line of thought.

As far as amps go, some amps have slightly different deep bass qualities, but these differences are not comparable to the influence of room acoustics.

The Vandersteen subwoofers (2Wq and V2W) are meant to be used with full-range speakers due to the contour (slope) of the crossover. The Vandy subs cross over at 80Hz, using a more gradual slope (I can't remember if it's a first order or second order filter, but I think the latter). Hence, there needs to a full octave overlap, covering the 40-80Hz range, for the Vandy subs to blend seamlessly with the main speakers.