ALC280 no play basses

I have a Dell Optiflex 3020 comes with Ubuntu 12.04 TLS

carte 0: MID [HDA Intel MID], périphérique 3: HDMI 0 [HDMI 0]
  Sous-périphériques: 1/1
  Sous-périphérique #0: subdevice #0
carte 1: PCH [HDA Intel PCH], périphérique 0: ALC280 Analog [ALC280 Analog]
  Sous-périphériques: 1/1
  Sous-périphérique #0: subdevice #0

Map 1 does not reproduce bass output, the sound in general is metallic, it is very disagreeable.
I created a windows partion, whether the windows driver or the driver realtek they both produce a correct sound.
Thank you for helping me to improve the sound of my Ubuntu 12.04 TLS