Comment 31 for bug 1553685

AFAIK the pin for the subwoofer output is 0x17:

see this section of my alsa-info.txt attachment:

Node 0x17 [Pin Complex] wcaps 0x40050c: Mono Amp-Out
  Control: name="Bass Speaker Playback Switch", index=0, device=0
    ControlAmp: chs=1, dir=Out, idx=0, ofs=0
  Amp-Out caps: ofs=0x00, nsteps=0x00, stepsize=0x00, mute=1
  Amp-Out vals: [0x00]
  Pincap 0x00000010: OUT
  Pin Default 0x40000000: [N/A] Line Out at Ext N/A
    Conn = Unknown, Color = Unknown
    DefAssociation = 0x0, Sequence = 0x0
  Pin-ctls: 0x40: OUT
  Power states: D0 D1 D2 D3 EPSS
  Power: setting=D0, actual=D0
  Connection: 1
     0x0f