Hi: Welcome to Linux Questions!-
Sorry I don't have experence with those particular speakers.
If you already purchased those speakers you can try:
commenting out the contents of snd_usb_create_mixer in the source alsa-driver-1.0.25/sound/usb/mixer.c:
By putting the # (pound sign) in front of the argument-
int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif,
> int ignore_error)
Or you could try a more current version of the kernel.
I like Logitech products and they work well with my Fedora and Black Opal machine.
The Z323 speakers and subwoofer work very well:-