See ..

http://code.google.com/p/voodoohda/issues/detail?id=170

... for a significant discussion of the subject.

After fiddling and farting around with a number of developmental versions
of Voodoo, settling on the one identified, above, which is Version 2.7.3,
solved my sound problems.

Developmental Version 2.7.4, mentioned on tonymacx86's site as a possible
solution, apparently has no support for the AD1884A codec.

Note that it is indeed possible for the FIRST boot after installing Voodoo
to give a KP in Voodoo. Just reboot and the KP should be gone.

Status is as follows:

1) Voodoo 0.2.1 works (supports the AD1884A codec, among many others), but
the settings are not "persistent" and often wind up being "indeterminate"
with no sound devices actually being simulated,

2) Voodoo 2.7.4 does not work (does not support the AD1884A codec, although
it may support many others), the settings are indeed "persistent",

3) Voodoo 2.7.3 works (supports the AD1884A codec, among many others), the
settings are indeed "persistent" and you are offered (amongst others) the
Line-Out jack (green) and the Line-In jack (blue); you may also select the
front panel's jacks, or any combination.

Volume level is good with 2.7.3 ... is much better than with 0.2.1, which I
found to be very weak.

Alas, there are some anomalies:

1) the volume control is "scratchy" as you actuate the slider, but it is
quiet when you finally settle on a setting, and

2) the volume can actually be too high, and can lead to speaker distortion,
if you are using a powered speaker.

Here's an About This  Mac... Sound display:

Devices:

Line-out (Green Rear):

  Default Output Device:    Yes
  Default System Output Device:    Yes
  Manufacturer:    Voodoo
  Output Channels:    2
  Current SampleRate:    192000
  Transport:    Unknown

Line-in (Blue Rear):

  Default Input Device:    Yes
  Input Channels:    2
  Manufacturer:    Voodoo
  Current SampleRate:    192000
  Transport:    Unknown

Headphones (Black Front):

  Manufacturer:    Voodoo
  Output Channels:    2
  Current SampleRate:    192000
  Transport:    Unknown

Microphone (Black Front):

  Input Channels:    2
  Manufacturer:    Voodoo
  Current SampleRate:    192000
  Transport:    Unknown