But those are the frequencies that contain all the harmonics, which are influenced by the various cone resonances and breakups in the loudspeaker, that give the speaker its tone, and distinguish one speaker from another.Never heard complaints from anyone about that, and the range where the frequency peaks in the graph is where its typically rolled of in a mix.
https://celestion.com/product/g12m-greenback/
remember that the loudspeaker is not there to reproduce exactly the tone from the instrument, the loudspeaker is part of the instrument; and so is, unfortunately, the lead between guitar and amplifier.
