Music not working when running on Windows 3.1 in DOSBox

Hello all,
The other day I picked up a copy of the classic version of Civilization II on CD-ROM.
So, on my Windows 7 laptop I launched DOSBox and installed Windows 3.1 using an external USB floppy disk drive which I mounted in DOSBox as A:
I then installed drivers for sound (Soundblaster 16) and video (256 colours).
After that, I put my Civilization II disc into the CD-ROM and mounted it in DOSBox with the following command:
mount D: D:\ -t cdrom
I went back into Windows 3.1, went into file manager, and started setup.exe. I went through the setup process with no problems whatsoever.
I then started Civilization II, keeping in mind my disc was still mounted and in the drive. I could hear the disc spinning in the drive and then saw the opening video. All was good and I had music on the main menu. The problem was when I was in the game there was no music and when I went to: File > Pick Music, It said:
This option is not available unless the Civilization II CD is in the CDROM drive.
I then went to: Advisors > Consult High Council and once again I could hear the disc spinning away and I got the videos of them speaking.

I don't know why I am getting the videos from the disc but not the music.
It all works perfectly fine apart from the in-game music.

If you have any idea please reply.
Thanks

 

Did you add the CD audio drivers in Windows 3.1?

Control Panel -> Drivers -> Add... -> [MCI] CD Audio

 

Thanks a lot,
It works perfectly. I can finally play Civ2 with the music.