There are some releases of the CD version that have bugs which are fixed by patches available at Patches Scrolls. One patch is for an issue with the keyboard, and another for SB.

The US release I have appears to include an already-patched version of CHAOS.EXE on the disc.

I am able to run the game with stutter-free sound in DOSBox, whether it's with Roland sound or another music device. Note that if you are using output=opengl then you may need to disable v-sync on the host, because v-sync can cause stutter. Also, I recommend using a BIN/CUE image of the game disc as it can help avoid issues with CD audio on real optical drives.

Perfect, thank you! I bought sealed CD US version on E-Bay. Perhaps I need the patch for SB 😀 !!

Thanks for the tip with DosBox. I tried DosBox-X (tried also DosBox SVN Daum) with this opengl yes....I'm playing on Samsung QLED with Radeon, which can do VRR (variable refresh rate), so mostly I have v-sync off. But I need to double check that. Perhaps I can also use double buffering option. But DosBox is not really an option, because on dual PIII-900Mhz it is not enough and i7-4930k does not have cd drive nor gameport for Roland. I would need to get some gameport for PCIe. Yes, I downloaded BIN/CUE image off internet as well. That's the one I tried in DosBox.

If you use a BIN/CUE image then your i7 doesn't need a CD drive to run the game, because DOSBox can mount the image directly. Also, there are USB-to-MIDI adapters to use instead of a gameport (presuming you want to use a real Roland MT-32, because of course you could use MUNT instead). Anyway, good luck with your efforts, and know that it is possible to run the game smoothly in DOSBox, though patches and configuration tweaking may be needed.

Ok, thank you very much for the hints and help! I already tried MUNT and various configuration. I forgot I'm a music producer and have full blown expensive studio soundcard with midi here...just got attached to gameport somehow, hehe. I run SC-55 in MT-32 mode, which is not 100% MT-32. The music in Chaos Engine sounds great. There is a little bit of overdrive. I tried various settings in MUNT (like clipping), but it did not sound exactly like that. The sample sounds similar, but the result sounds different. With MUNT it sounds like it does not have "the balls" in music. This might be my obsession though as I have trained ears and can even hear very quiet stuff across the wall.

Yes, I did mount the BIN/CUE under DosBox.

Seems like even DosBox needs a looooot of tweaking. That keeps me happy, because I can play with real hardware and have no regrets 😀.

Another thing I don't like on DosBox is the scaler. Yes, I remember now! The scaler is annoying. In Chaos Engine, and other titles, it is either blurry or stretched. TV is set to 4:3, of course. I use OSSC (FPGA unit) as VGA scaler (including sound) to HDMI. The line doubling feature and optional scanline filter is so amazing, like on real CRT. Pixel perfect, sharp. In Dosbox I can use some 2x scaler, which is closest to sharp, but the resolution is lower, there are black borders on top & bottom. I was on FreeDOS mailing list, solving CD-ROM driver & protection feature and mentioned OSSC. They did not know it and read about it and said that I could recommend to a DosBox author implementing this style of scaling algorithm.

Also real Voodoo hardware has different texture filtering. I did notice it on Quake 2 (same machine Geforce 3 vs Voodoo 2). Tried also some DosBox-X with Glide support. It did not look like that. The modern OpenGL is too sharp, whereas the Voodoo 2 filtering is more blur when it is more far from the viewport.

These are the little bits that keep me from using DosBox and that's why I will try to run it on the real hardware first (also invested a lot in this hardware and gameport gamepads for two players).