Where to begin? First of all, "full range" means nothing. It's advertising copy. Buyer beware. (All right, when a-philes use the term, they DO mean something close to 20-20kHz. But any manufacturer can call any speaker in its line "full range.")
Marakanetz is right that many speakers can indeed produce some very low bass output. What matters is whether it's flat, vis-a-vis the midrange. And Onhwy61 is right about speaker-room interaction.
Pairing what we might call a "reasonably full range" speaker with a subwoofer can be advantageous, since you have more flexibility on the crossover.
As for amps, they cannot put back what a speaker takes away. (If they do, I'd suggest finding another amp.) Going in the other direction, if a tube amp is rolling off the low end, adding a sub and cranking it up (or tweaking an equalizer, which amounts to the same thing) will give you more bass, but not generally the kind of more you want.
If you like the sound of a tube amp that rolls off the bass, then trying to put back the bass makes no sense. If you want full-range sound, you need both a full-range amp (which includes many tube amps and most SS amps) and a full-range speaker system--which means either a large speaker with a large driver (or combination of drivers) or a sub.
Marakanetz is right that many speakers can indeed produce some very low bass output. What matters is whether it's flat, vis-a-vis the midrange. And Onhwy61 is right about speaker-room interaction.
Pairing what we might call a "reasonably full range" speaker with a subwoofer can be advantageous, since you have more flexibility on the crossover.
As for amps, they cannot put back what a speaker takes away. (If they do, I'd suggest finding another amp.) Going in the other direction, if a tube amp is rolling off the low end, adding a sub and cranking it up (or tweaking an equalizer, which amounts to the same thing) will give you more bass, but not generally the kind of more you want.
If you like the sound of a tube amp that rolls off the bass, then trying to put back the bass makes no sense. If you want full-range sound, you need both a full-range amp (which includes many tube amps and most SS amps) and a full-range speaker system--which means either a large speaker with a large driver (or combination of drivers) or a sub.