Playing oldgame in Dosbox, is sound blaster or Roland better?
Audio quality is somewhat subjective, although it's my opinion that the Roland MT-32 produced superior music quality. You can compare them with a number of videos on YouTube. Here's one for Space Quest 3:
Sound Blaster:
Roland MT-32:
The Roland audio offers a bit better quality, has reverb effects, actual MIDI "instruments," is in stereo, etc.
DOSBox, however, doesn't emulate the Roland MT-32. It only passes MIDI data to whatever MIDI devices are available on your PC. This might be the actual Roland hardware, although that's unlikely in this day and age. However, most modern sound cards have rudimentary support for MIDI, but the quality depends on your card, its drivers, etc. There are a few 3rd party MIDI device emulators for DOSBox - there's a good article on their wiki about setting them up.
So, to summarize, you'll probably get a better quality out of the MT-32 option, but only if you take the time to set it up and configure DOSBox/your PC properly.
Boxer.app, a popular DOSBOX wrapper for Macs, has recommendations for preferred sound systems in the help file. They are (in order from best to worst)
- Gravis Ultrasound / Max. Not many games offer it, but it's the best choice when they do.
- General MIDI (MPU-401). Better music. Can be paired with Sound Blaster 16 for digital audio.
- Roland MT-32. Predecessor to General MIDI.
- Sound Blaster. 16 if available, otherwise pro or regular. "Most reliable"
- AdLib. Not as good as Sound Blaster.
- Disney Sound Source / Tandy 3-voice sound, two obscure options
- PC speaker
Boxer added special Roland MT-32 support in 2011; it's possible this isn't available in other DOSBOX variants.
On my PC, I found that for this particular game - Maddog Williams - Sound Blaster sounded better. Roland played a constant high tone behind the music.