acd tells the CD-ROM drive to play. if there is no audio cable connecting your CD-ROM drive and your sound card, the (electrical) audio signal isn't going to make it to your speakers.
acd does *not* read the digital pcm off the cd and relay it to the sound card. that method, now common, was not reliable when i wrote acd. this difference probably explains the cd light difference you've observed. if there is a cable connecting your CD-ROM drive and you're still not getting sound, it's probably because the sound card's cd volume is at 0. cat /dev/volume to see and echo cd 50 >/dev/volume to change. russ