Hi,
I think you have the SB16 hanging note issue, which happens in duke nukem 3d when playing midi combined with digital sound effects.
Which soundblaster 16 model do you have specifically ?
--> read about it here : https://www.vogonswiki.com/index.php/Hanging_note_bug
Affected cards
Affected are all Sound Blaster models with DSP revisions 4.11, 4.12 and 4.13.
Type 1 doesn't occur on cards with a CT1747 bus interface.

Bugged (Type 1 and 2)
CT1740 (DSP >4.05) - SB 16 CSP
CT1750 (DSP >4.05) - SB 16 Multi-CD CSP
CT1770 (DSP >4.05) - SB 16 SCSI-2
CT2260 - SB 16 Multi-CD OEM
CT2800 - SB 16 Value OEM
CT2860 - SB 16 Value OEM
CT2910 - SB 16 Pro
CT2940 - SB 16 Value PnP OEM
CT2950 - SB 16 Value PnP OEM
CT2980 - SB 16 Value PnP
CT3600 - SB AWE 32 IDE PnP
CT3990 - SB AWE 32 IDE PnP
Bugged (Type 2 only)
CT2230 - SB 16 Multi-CD CSP
CT2290 - SB 16 PRO CSP
CT2760 - SB AWE 32 Multi-CD
CT3900 - SB AWE 32 IDE
CT3980 - SB AWE 32 IDE
Bug-free
CT1730 - SB 16
CT1740 (DSP ≤4.05) - SB 16 CSP
CT1750 (DSP 4.05) - SB 16 Multi-CD CSP
CT1770 (DSP 4.05) - SB 16 SCSI-2
AWE64 cards (DSP 4.16)

Thanks for the reply dreamblaster! I have a CT 1740 (OG SB 16 is my most nostalgic card haha), and very much affected by the bug. However before we write this off as the bug...I dont think thats what I am experiencing, because I am fully aware what the hanging note bug is and what it sounds like. As referenced on the page you linked '... the bug manifests itself as "rogue" MIDI notes being generated during MIDI playback. Since these notes are not part of the soundtrack, they are not stopped and hang for a long time. Also, these 'illegitimate' notes tend to be high-pitched, which makes this variant of the bug a rather annoying experience.'

I am not hearing any rogue notes or long hanging notes. My game hitches (like it loads for a second) here and there when playing. The game literally stops for maybe half of a second then goes again and this seems to be affected by the number of assets on the screen. And finally that issue goes away completely when using the SB 16 for all aspects (and I still have the dreamblaster installed, just not selected). Its enough to make me just play Duke in SB 16 mode, but I was hoping maybe there was a setting that I didnt know about that I could try to tinker with.

Thanks again for the reply! I love the waveblaster, and I will say that I haven't noticed this issue any other games yet. Also I havent done what I would call extensive testing...i.e. I havent pulled the card out and put it in one of my other old machines with totally different hardware and see if the issue follows or not. I dont think I am concerned enough to go to that lengths to figure it out, was just hoping for any tips you all might be able to provide.

What IRQ are you using for the MPU-401 interface?

This is another SB16 bug than the hanging note bug. Apparently lowering the sfx mixing rate helps.

I have read that MIDI output stutters on SB16 cards when you use higher than 22KHz sample rate.