Mount c c:\dosgames or where you plan to put it
Mount E D:\ -t cdrom
The instructions to dosbox are simple. Just look on you tube.

Mount E D:\ -t cdrom
Mount D E:\ -t cdrom

Just change to "D:" and then type in "hdinst".

This is what the CDs contents should look like:

There is a Sound Canvas mode to this game and no support for it in software.

GM support was added in the v1.4 patch.

But how do you get playback in Windows 10 without buying an Integra 7?

General Midi in Xcom games. <- Midi-Fix

To change the midi device type

mixer /listmidi

into DOSBox and then change the number at

[midi]
midiconfig=

in the DOSBox config file to whatever device you want to use.

Keep in mind though, UFO sounds best using the SB16/AdLib settings.

Every other option, this includes MT-32, GUS, etc. will sound inferior.

TFTD = GUS
Apocalypse = CD Music

What about the Microsoft GS Wavetable Synth? Shouldn't that work with DOSBox X by default?

K, I'm snarfing halfling weed or something. There is no sound canvas mode. It works much better in General MIDI mode than OPL2 mode. So there are no worries. It's kind of nice that DOSBox X does OPL3 emulation, it's so much better than regular DOSBox.

There is a place to offer soundfont emulation. I suppose that's the upgrade path.

It's curious that it has essentially a Soundblaster Pro music mode without a Soundblaster 16 music mode.

The way I get General MIDI to work is from setup.exe.

Gm.dls is version 1.00.16, it sounds a little better than expected.

The original DOS version of this game is hard to find. Does anyone know when it came out?

This version is on Mobygames
https://www.mobygames.com/game/dos/x-com-ufo-defense

The wikipedia says the initial release of the game was in 1994. On CD? Nonsense.

Something is nonsense here, games released on CD in 1994 are not if that is what you were implying.
I haven't bothered to check my collection to see when the game was released on CD.
I'm not sure why you would bother posting this here. If it's wrong then correct it.

I am asking when it was released on floppy disk.

Why did you edit the subject line to refer to "CD-i"? That is beyond nonsense.

I was trying to match one of the platform titles at Mobygames. They didn't have a separate designation for DOS CD from the beginning but they have used it.

CD-i is an entirely different platform that has nothing to do with DOS or XCOM aside from the use of optical media.

Now they're saying the CD version is 1995 and the floppies are 1994.

That's correct, but there are more release than that.

Amiga AGA (floppy) and DOS Floppy release in 1994.

Then later :
Amiga CD32 (CD)
Windows 95 CD ("Gold") release
Steam digital download release (which uses the DOS and Win9X releases)
PSX release

Possibly more that I forgot, but I doubt it.

I've played the game on an Amiga 500 so there must be a non-AGA version of it, too.

In XCom, AWE32 has got to be the OPL3 mode. This mode doesn't work on this game and I suppose it is a feature request.

The images of the floppy disk version on Mobygames are wrong, there are at least 4 disks for that version.
Wrong! It's a bug with DOSBox -X

Also, the Soniqbear soundfont is much better than the SC-880 soundfont. The synergi soundfont, while ordinarily excellent, just isn't loud enough. The BGM needs to compete with machine gun fire in the intro.

That aside, there is a real bug with the game. The default IRQ of 5 is not compatible with soundblaster 16 audio.