you can, but it's limited to a single sound file that will loop repeatedly (you can make it really long, i guess) but it's not fully mod-compatible as of yet (it doesn't take mod indexing into account), you'd need to define any extra audio in xcom1ruleset.rul for it to not cause conflicts. mod indexing needs to be altered as it is, to allow for better support of tftd, as the files contain different amounts of information.