O som Nvidia HDMI e os fones de ouvido Logitech não funcionam em 14.04

Question

Não há som saindo da porta HDMI da minha placa Nvidia para a minha tv que estou usando como monitor. Quando uso meus fones de ouvido Logitech, também não ouço nenhum som. Alguém sabe como corrigir a situação? Aqui estão alguns screenshots e informações do sistema (desculpe se isso é muita informação):

• Ubuntu Server 14.04
• Fluxbox WM
• SABERTOOTH 990FX / GEN3 R2.0
• Processador AMD FX (tm) -8350 de oito núcleos
• GeForce GTX 660 Ti (drivers da Nvidia 331.20)
• Fone de ouvido / microfone Logitech G35

saída aplay -L:

default
Playback/recording through the PulseAudio sound server
null
Discard all samples (playback) or generate zero samples (capture)
pulse
PulseAudio Sound Server
sysdefault:CARD=SB
HDA ATI SB, ALC892 Analog
Default Audio Device
front:CARD=SB,DEV=0
HDA ATI SB, ALC892 Analog
Front speakers
surround40:CARD=SB,DEV=0
HDA ATI SB, ALC892 Analog
4.0 Surround output to Front and Rear speakers
surround41:CARD=SB,DEV=0
HDA ATI SB, ALC892 Analog
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=SB,DEV=0
HDA ATI SB, ALC892 Analog
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=SB,DEV=0
HDA ATI SB, ALC892 Analog
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=SB,DEV=0
HDA ATI SB, ALC892 Analog
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=SB,DEV=0
HDA ATI SB, ALC892 Digital
IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=SB,DEV=0
HDA ATI SB, ALC892 Analog
Direct sample mixing device
dmix:CARD=SB,DEV=1
HDA ATI SB, ALC892 Digital
Direct sample mixing device
dsnoop:CARD=SB,DEV=0
HDA ATI SB, ALC892 Analog
Direct sample snooping device
dsnoop:CARD=SB,DEV=1
HDA ATI SB, ALC892 Digital
Direct sample snooping device
hw:CARD=SB,DEV=0
HDA ATI SB, ALC892 Analog
Direct hardware device without any conversions
hw:CARD=SB,DEV=1
HDA ATI SB, ALC892 Digital
Direct hardware device without any conversions
plughw:CARD=SB,DEV=0
HDA ATI SB, ALC892 Analog
Hardware device with all software conversions
plughw:CARD=SB,DEV=1
HDA ATI SB, ALC892 Digital
Hardware device with all software conversions
hdmi:CARD=NVidia,DEV=0
HDA NVidia, HDMI 0
HDMI Audio Output
hdmi:CARD=NVidia,DEV=1
HDA NVidia, HDMI 1
HDMI Audio Output
hdmi:CARD=NVidia,DEV=2
HDA NVidia, HDMI 2
HDMI Audio Output
hdmi:CARD=NVidia,DEV=3
HDA NVidia, HDMI 3
HDMI Audio Output
dmix:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Direct sample mixing device
dmix:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Direct sample mixing device
dmix:CARD=NVidia,DEV=8
HDA NVidia, HDMI 2
Direct sample mixing device
dmix:CARD=NVidia,DEV=9
HDA NVidia, HDMI 3
Direct sample mixing device
dsnoop:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Direct sample snooping device
dsnoop:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Direct sample snooping device
dsnoop:CARD=NVidia,DEV=8
HDA NVidia, HDMI 2
Direct sample snooping device
dsnoop:CARD=NVidia,DEV=9
HDA NVidia, HDMI 3
Direct sample snooping device
hw:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Direct hardware device without any conversions
hw:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Direct hardware device without any conversions
hw:CARD=NVidia,DEV=8
HDA NVidia, HDMI 2
Direct hardware device without any conversions
hw:CARD=NVidia,DEV=9
HDA NVidia, HDMI 3
Direct hardware device without any conversions
plughw:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Hardware device with all software conversions
plughw:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Hardware device with all software conversions
plughw:CARD=NVidia,DEV=8
HDA NVidia, HDMI 2
Hardware device with all software conversions
plughw:CARD=NVidia,DEV=9
HDA NVidia, HDMI 3
Hardware device with all software conversions
sysdefault:CARD=Headset
Logitech G35 Headset, USB Audio
Default Audio Device
front:CARD=Headset,DEV=0
Logitech G35 Headset, USB Audio
Front speakers
surround40:CARD=Headset,DEV=0
Logitech G35 Headset, USB Audio
4.0 Surround output to Front and Rear speakers
surround41:CARD=Headset,DEV=0
Logitech G35 Headset, USB Audio
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Headset,DEV=0
Logitech G35 Headset, USB Audio
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Headset,DEV=0
Logitech G35 Headset, USB Audio
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Headset,DEV=0
Logitech G35 Headset, USB Audio
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=Headset,DEV=0
Logitech G35 Headset, USB Audio
IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=Headset,DEV=0
Logitech G35 Headset, USB Audio
Direct sample mixing device
dsnoop:CARD=Headset,DEV=0
Logitech G35 Headset, USB Audio
Direct sample snooping device
hw:CARD=Headset,DEV=0
Logitech G35 Headset, USB Audio
Direct hardware device without any conversions
plughw:CARD=Headset,DEV=0
Logitech G35 Headset, USB Audio
Hardware device with all software conversions

aplay -l output:

**** List of PLAYBACK Hardware Devices ****
card 0: SB [HDA ATI SB], device 0: ALC892 Analog [ALC892 Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: SB [HDA ATI SB], device 1: ALC892 Digital [ALC892 Digital]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 3: HDMI 0 [HDMI 0]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 7: HDMI 1 [HDMI 1]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 8: HDMI 2 [HDMI 2]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 9: HDMI 3 [HDMI 3]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 2: Headset [Logitech G35 Headset], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0

Os volumes do fone de ouvido parecem normais, mas os volumes da minha saída HDMI são assim:

Alémdisso,nadaaparecenaguiaHDMInognome-alsamixer