I've been using a Firewave since 10.5 on my Hackies. I haven't had any issues with it and don't need to worry about futzing around with audio drives. However, I think the little booger might finally be biting the dust.
I've seen this in 10.8 and 10.9. Sometimes when I boot, it'll be silent. I can adjust the audio and see the overlay, but no sound. If I go into Audio MIDI Setup and change the format to 48/44.1 (just switching it works), I'll get sound again. However, I also have occasional audio cutouts. It'll work fine, and then the next thing I know it's either dead silent or stuttering with the last sound ad infinitum. Adjusting the audio with a hotkey takes 5-10 seconds before the overlay shows, almost like it's choking on something, but makes no difference. Rebooting works, but always requires the format trick to get sound back once you do. I've seen this in the System log when it happens:
9/14/14 7:58:48.000 PM kernel: Write for 0xffffff80266c3500 done, status e00002d6
The address may change, but I believe the status is always the same. I've seen reports of similar things with other Firewire peripherals. I've tried a different cable, but no luck. I've had it plugged into a PCIe Firewire 400/800 card with a TI chipset for some time. I tried switching back to the onboard Via chipset. No luck. I tried uninstalling and reinstalling the aging Firewave software. No luck. If it's in the silent/stuttering state, opening up the Firewave application is also quite sluggish, as is the UI. It's like anything trying to access it is blocked to hell. I'm thinking that either compatibility is finally catching up to this old thing or it's just outright dying. I hope not. I'd like to get many more years out of it.