The Allan Holdsworth Fatboy HF2 (https://www.kieselguitars.com/series/guitar/allan-holdsworth-fatboy) includes a birch top and back wood standard, allowing for increased chambering of the body. This design element increases the instrument's sustain and dynamics. The guitar's bracing consists of two “I” beams, which allow for no part of the top or back, besides a small section behind the bridge, to touch the inside of the guitar. This construction method lets the top and back woods resonate more freely.
"When you've got a hollower guitar, it actually slows down some of the attack; it doesn't slow down the initial attack. It slows down everything else, so it becomes more Dynamic. You know you can play a note softer and even with a distorted sound and still get that kind of dynamic quality to it." -Allan Holdsworth
Download the HyperRig Kiesel preset used in this video: https://www.dropbox.com/scl/fi/42lvstczfd7lrburqzi6w/Holdsworth-y.pdpreset?rlkey=rhn461udaen3t79w5drybb7io&st=3rjbjdm2&dl=0
Backing Track by Daniele Raciti: https://www.youtube.com/watch?v=p2uZlLeiDTQ&ab_channel=DanieleRaciti