Originally Posted by oldcpu
Did you try controlling the volume with the pulse audio volume control app 'pavucontrol' ?
no- I dual-boot the KDE Spin of F15 so I use KMix instead of PulseAudio so I can't use pavucontrol.
EDIT: Wait a minute... I have pulseaudio installed... I'll see what happens when I download pavucontrol.
EDIT EDIT: Hm, this is interesting. KMix was adjusting the volume on "Redwood HDMI Audio [Radeon HD 5600 Series] Digital Sterio (HDMI)". pavucontrol sensed 2 output devices: the one I just listed, and "Internal Audio Analog Stereo". It seems like the first choice would be the correct one, but the internal stereo is the correct one. idk why.
Anyways, it's working now. Thanks for suggesting "pavucontrol"; it made me realize I was using the wrong device.