If your sound card previously did not work, a recent fix suggested by Barry Bouwsma and committed by Matthew Dillon may fix it. If you have a SF64-PCR sound card, a change in make.conf will be needed, as described in the link above.
A running description of activity related to DragonFly BSD.
A quick Google shows this is a radio tuner card, and the commit suggests that it doesn’t take audio in the outgoing direction (as in: *not* a soundcard, just a sampler), while the manufacturer’s abuse of the PCI ID made some *actual* sound cards be detected as it. [So if you have the *radio* card with that ID, you now have to add the option to keep the system from trying to spin up audio output to ‘nowhere’ … while everything with the FM801 sound chip will now be enabled as a full soundcard by default.]
If anyone else was wondering.