I tried playing The 7th Guest in my 486DX2/66 yesterday and noticed that the digital audio was skipping terribly. The MIDI and CD Audio were OK. The digital audio, including music and sound effects, was so bad that the voices were often unintelligible. At first I thought it was my Sound Blaster 16, so I updated the game to v1.30, the last pure DOS version. This adds SB16 support. Problem was not fixed. Then I thought it could be my Cirrus Logic VLB graphics card, which the game notes that it has issues with some of these. Tried a VESA TSR, issue not fixed and screen updates were remarkably slow. I tried using the 320x200 graphics mode, but the issue was not fixed and the graphics were quite ugly. Finally I tried using the OPL3 for music instead of the Roland Sound Canvas SC-55, and the digital audio played without a hitch.

My external SC-55 was connected to the SB16 with a MIDI/Joystick cable, so I thought I would have to use another card. Then in searching this issue, a mention of SBMPU401.EXE popped up but it was not discussing this issue. My memory of the program flooded back and I tried it out with the /E switch. Problem fixed. Now I can enjoy the game as the developers meant me to play it. (The manual specifically mentions the Sound Canvas). I just thought I would share this for posterity.