Page "Gravis Ultrasound" Paragraph 34

As the GF1 chip does not contain AdLib-compatible OPL2 circuitry or a codec chip, Sound Blaster compatibility was difficult to achieve at best.

Consumers were expected to learn how to tweak the emulation software used to emulate other standards, an activity not necessary with many other cards that emulated the Sound Blaster through their sound hardware.

The emulation software ran as a huge TSR that was difficult to manage in the pre-Windows days of complicated DOS extenders.