Bandwidth is the frequency range that the amp or the cab can transmit. The critical points are (lower apart from the linearity) the lower and upper frequency limits, ie deep basses and silky heights. A high bandwidth (at least 80 to 15,000 Hz) is the basic prerequisite for an FRFR amplifier.
Example 1: GFR (guitar flat response)
The “Camper 112” with its restricted frequency range from 100 to 10,000 Hz can not represent a low bass and also silky heights. The frequencies, which would be annoying for guitarists who love combos, anyway only annoying, the “Camper 112” does not even at all. Shrunken heights, which can be a problem with FRFR, remain the same on the outside of the “Camper 112”. The amp sounds like a small combo. Advantage: The modelings of the virtual guitar cabs in Kemper, Axe-FX and Co. can nevertheless be used due to the given linearity of the BlueAmps. The larger stereo model “Camper 212” has more bass, but is dampened in the heights – just like a real combo.
Bxample 2: FRFR (full range flat response)
Metal guitarists often prefer amps and basses with deep bass. A BlueAmps “212 FR-A” or the passive version “212 FR” can be questioned here – Depth down to 55 Hz. So it pushes the lows significantly more and provides for troubadour flaps and grins on the face. Heights up to 15 kHz are also a feature. If you do not need the trouser leg, the “Camper CX” or the BlueAmps “Blue 3” is the right decision.
The bandwidth and thus speaker modeling is fully usable with all FRFR amps. The entire human auditory range is covered. This is called “full range”.