Audio Search being a fairly new technology, there are a bunch of caveats:
-The recording must have been recorded with a microphone that is less than 6
inches away from the speaker. For any distances greater than that, the
recognition does not do well.
-The recording setting in Tools > Options > Audio and Video must be set to
at least 16kbps, 16KHz, mono. And the higher the kbps the better.
-You need to leave your computer idle with OneNote running, and not on
battery, for several hours in order for OneNote to index audio, because the
recording takes about 2-3x-realtime to index, depending on your CPU. So the
best idea is to leave your computer plugged in to power and running OneNote
for the nights for it to index recordings that you make during the day. Make
sure that you computer is not set to automatically set to go to sleep on idle.
The mechanism is that OneNote starts indexing after it notices that the
computer has been idle for 7 minutes.
- Audio search won't work if you don't have WDS.
I suggest checking the OneNote Guide "More Cool Features" section for the
suggestions on Audio Search. It has some suggestions on how to phrase your
search terms to have a better chance of finding stuff. For example short
words are more likely to turn up incorrect results.
In post-B2TR builds we made a fix that tells you how many recordings have
not been indexed yet.
Hope this helps,