Malcolm Moore explains why limitations are not preferable
“For a guitar, the audio spectrum needs are wide. …The lower open E string has a fundamental of about 128 Hz, and significant harmonics are the second, fourth, sixth and eighth meaning the spectrum here extends to 1024 Hz. On the twelfth fret on the upper E string the fundamental is about 1,024 Hz, and the spectrum extends to about 8.192 kHz. On the 21st fret the fundamental at C# is about 1,722 Hz, and the spectrum extends to almost 14 kHz! The…frequency response needs to be virtually flat from less than 100 Hz to greater than 14 kHz to faithfully reproduce the vibrations from the guitar strings – before anybody starts to play with the audio spectrum, develop distortion, or introduce echo and / or reverberation.”
At the same time, a 12-inch speaker is probably not reproducing anything over 5 kHz.
At the same time, the “bright” switches common on many amps significantly boost the high frequency response, apparently in attempt to bring-up the highs in the final output – and undo the loss from the speaker and even perhaps the amp…which most likely leads to all kinds of zany weird distortions in the higher frequencies. Some people love that, some don’t, and there’s so many different kinds of speakers, perhaps thousands. And maybe that many amps. And tubes. And guitars. And strings. And pickups! And players.
So I think it’s fairly impossible to make any kind of sweeping statement regarding ‘limited bandwidth’ other than to explain that one purpose of GAGA is purity and clarity of tone, and we feel that begins with more faithfully amplifying whatever signal is put in, not in creating some kind of subjective-to-us, inescapable bandwidth-limiting filter/amp. There apparently are plenty of those already, and just because that’s been done for decades (a) doesn’t make it right or better, and (b) definitely means we don’t want to ‘me-too’ that. (I can’t recall a single GAGA player who’s ever complained about too much high-end.) Meanwhile, so many guitar books and mavens advise to start with the best possible clean tone – it’s the only sane starting point. Everything and anything else can then be added and/or taken away from the final tone.
When we say “high-end” we don’t say (or mean) “hi-fi” as in a dry, 2D, direct-into-mixing-board, lifeless tone. Instead, we refer more to the quality of build, design considerations, etc.