Sonic 1 Soundfont Page

The Genesis couldn't produce sub-bass below 60Hz. If you boost the low end on a Sonic 1 soundfont, you are adding frequencies that never existed. Keep the bass punchy in the 100-200Hz range.

A paid option (rare for Soundfonts) that uses 24-bit sampling. It captures the analog output of a model 1 Genesis (which has a superior sound chip to later models). The bass is noticeably warmer. sonic 1 soundfont