Thank you for trying. I didn't notice either at first how different the effects sounded when I had the sounblaster option selected.
I just tried the game on a real DOS computer. When I choose soundblaster or adlib I hear, what I believe to be, the correct sound effects. The same effects I hear when I choose internal speaker in DosBox, but without the popping noise. I tried the internal speaker option on my real DOS computer but the effects coming through the actual internal speaker are very low. I can barely hear them unfortunately. But anyway, this is clearly an issue with DosBox as the soundlbaster\adlib option works correctly on my real DOS computer.
I don't know what it is I am hearing when I choose the soundblaster or adlib option in DosBox but it does not sound as good as the internal speaker option. *Maybe* its playing FM synthesized effects instead of digitized effects. Either that or DosBox is really messing up the sound effects when you choose adlib or soundblaster. Anyway, I'd rather have the good effects with the popping noise then the bad effects without the popping noise. 😜
Finally, whoever said the popping noise is caused by the internal speaker being turned on and off is correct. It is being switched on and off every single time an effect is played. There were talks (apparently) to leave the internal speaker on in the next version of DosBox.
Thanks again for running the test Xelasarg!