Cthugha uses controls on the soundcard to select an input: microphone, line-in, or CD. DOSBox does not support audio input in the SB or GUS emulation, and I haven't seen any attempts to implement it. There is a workaround to get the Creative Parrot to run, but it's not actual input. The few DOS programs I'm aware of that could use the feature aren't really games, in the strict sense, although they are for entertainment.

This is an old thread, but still a feature I'd like to see tackled. I know it's not a "game" but another piece of DOS eyecandy supporting mic/line-in input would be 2ynesthesia / Synesthesia IIx.

Can anyone suggest if other DOS VMs provide Soundblaster emulation? I know VirtualBox does, but 2ynesthesia won't proceed beyond it's initial image generation with it.

Just setup Cthugha myself to find that the CD input does not work. Makes sense though that the Sound Blaster CD input is not emulated though. That's too bad. I'd take stab at it but don't have the time right now.

Here is a game which uses a mic as a feature - Madspace, an obscure gem, that somehow got released on Steam. Description says nothing about that but it has voice control, not a necessary feature but would have been pretty nice. It also has VR headset support, a bit off, but how does Dosbox fairs with that?