As of 2021-07-29, our FC Tourmaline firmware has L1_NEW_AEC enabled.  As a
result of this change, auw 12 command (sent via fc-tmsh) takes 12 data number
arguments instead of 5, and the full capabilities of the AEC block in the DSP
can be exercised.

The 3 little one-line files given in this directory (aec-disable,
pirelli-handheld and pirelli-handfree) contain fc-tmsh auw 12 invokations with
different numbers, intended for manual experimentation with our new AEC - run,
for example, sh pirelli-handfree.  The 3 AEC configurations are:

* aec-disable is the default disabled state of the AEC block - the initial state
  of your FCDEV3B/Caramel2/etc board if you do nothing.

* pirelli-handheld is the AEC configuration extracted from Pirelli's firmware,
  used in the handheld mode.

* pirelli-handfree is the AEC configuration extracted from Pirelli's firmware,
  used in the hands-free loudspeaker mode.

Applying pirelli-handfree AEC config to an FCDEV3B setup with the "official"
FreeCalypso HQ loudspeaker and microphone produces noticeable improvement in
voice call quality, as perceived by the person on the far end of the call: the
delayed acoustic echo goes away, and the tester reported that my voice sounded
better too.