Like the Metamaterial Drum, a Metamaterial Guitar can be constructed using masses attached to the guitar top plate. When magnets are used, such masses are easily attached and de-attached or placed at different positions:
This creates a band-gap in the low frequency range when placing the magnets in a line next to the bridge:
Below, the blue curve is a classical guitar without magnats attached, the yellow curve that with heavy magnets. The sound is very unique, as guitars never have a band-gap of such a kind. Low frequencies are still loud, also upper mid-frequencies and high frequencies are present. Still around 300 Hz the guitard does not respond. The reason is a heavy distortion of the eigenmodes:
Magnets with low mass have the same effect, still much more subtle. The amount, mass, and placement of the magnets determine the strength and position of the frequency band-gap and therefore make alternations of guitar sounds.
In videos the influence of different magnets on the top plate vibrations can be seen:
No magnets:
Heavy Magnets right above the bridge:
Small magnets right above the bridge:
Small magnets between bridge and soundhole:
Small magnets at soundhole: