A low B note on a bass guitar is 30.9Hz. I have a cabinet that is rated for -3db @ ~33 Hz and I feel it helps, but I've never had my hands on a 37" scale to compare what would seem to be the best of both worlds.
A normal Ampeg 8x10 cabinet is only ~58 Hz @ -3db. Have you tried your Dingwall through a cabinet that is rated low enough to reproduce the fundamental?
Thanks,
Scott
Reference link for note to frequency chart -> https://pages.mtu.edu/~suits/notefreqs.html