Abri o Alsamixer, coloquei todos os volumes (menos o Master, já que estou com fone de ouvido...) no máximo, tentei gravar em todas as combinações de Perfil de Hardware e Conector de Entrada, possíveis, e ainda assim não captou o som do microfone.
O meu Alsamixer:
http://i52.tinypic.com/14v36vl.pnge eu digitei lspci, aqui está o resultado:
00:00.0 Host bridge: nVidia Corporation Device 0071 (rev a3)
00:00.1 RAM memory: nVidia Corporation Device 007f (rev a1)
00:00.2 RAM memory: nVidia Corporation Device 0075 (rev a1)
00:00.3 RAM memory: nVidia Corporation Device 006f (rev a1)
00:00.4 RAM memory: nVidia Corporation Device 00b4 (rev a1)
00:01.0 RAM memory: nVidia Corporation Device 0076 (rev a1)
00:01.1 RAM memory: nVidia Corporation Device 0078 (rev a1)
00:01.2 RAM memory: nVidia Corporation Device 0079 (rev a1)
00:01.3 RAM memory: nVidia Corporation Device 007a (rev a1)
00:01.4 RAM memory: nVidia Corporation Device 007b (rev a1)
00:01.5 RAM memory: nVidia Corporation Device 007c (rev a1)
00:01.6 RAM memory: nVidia Corporation Device 007d (rev a1)
00:02.0 PCI bridge: nVidia Corporation Device 007e (rev a2)
00:04.0 PCI bridge: nVidia Corporation Device 007e (rev a2)
00:05.0 PCI bridge: nVidia Corporation Device 007e (rev a2)
00:06.0 PCI bridge: nVidia Corporation Device 007e (rev a2)
00:07.0 PCI bridge: nVidia Corporation Device 007e (rev a2)
00:09.0 RAM memory: nVidia Corporation MCP51 Host Bridge (rev a2)
00:0a.0 ISA bridge: nVidia Corporation MCP51 LPC Bridge (rev a2)
00:0a.1 SMBus: nVidia Corporation MCP51 SMBus (rev a2)
00:0a.2 RAM memory: nVidia Corporation MCP51 Memory Controller 0 (rev a2)
00:0b.0 USB Controller: nVidia Corporation MCP51 USB Controller (rev a2)
00:0b.1 USB Controller: nVidia Corporation MCP51 USB Controller (rev a2)
00:0d.0 IDE interface: nVidia Corporation MCP51 IDE (rev a1)
00:0e.0 IDE interface: nVidia Corporation MCP51 Serial ATA Controller (rev a1)
00:0f.0 IDE interface: nVidia Corporation MCP51 Serial ATA Controller (rev a1)
00:10.0 PCI bridge: nVidia Corporation MCP51 PCI Bridge (rev a2)
00:10.1 Audio device: nVidia Corporation MCP51 High Definition Audio (rev a2)
01:00.0 VGA compatible controller: nVidia Corporation G72 [GeForce 7300 SE/7200 GS] (rev a1)
06:0c.0 Ethernet controller: Marvell Technology Group Ltd. 88E8001 Gigabit Ethernet Controller (rev 13)