I think a SoundBlaster is still the "hot shit" option for 1993. But you don't have to look for Pro version. There are probably three main alternatives:
1) SoundBlaster AWE32. Yes, it was released in 1994, but it's natively supported by Doom with patches (also by the Ultimate Doom edition)
2) SoundBlaster 16 + a Roland or a Yamaha device. That includes daughterboards (SCD-10, DB50XG), standalone units (SC-55, SC-88, MU80) and addon cards (SCC1, SW60XG). I guess the period correct option would be Roland SC-55 (released in 1993) and it's the device most of the Doom soundtrack was written on.
Bear in mind that many SoundBlasters suffer from hanging midi bug, particularly in Doom and Doom-based game. So you will have to find something like CT2230 or CT17** revision card. More details here. Or just go with an addon card — they don't have those issues.
3) SoundBlaster 16 + original Gravis Ultrasound. I believe that the GUS version is what you can hear in all official Doom ports on Steam/Xbox/etc.