Three points:
1. A new Sony Sony MZ-NH700 Hi-MD recorder (~$250) can record for 10
hours in "Hi-LP" mode (that's 64kbps ATRAC3plus) using a re-formatted
standard $1.50 minidisc. This is the cheapest way to collect the
overnight data, and it will permit a normal night's sleep.
2. The Hi-MD recorder will transfer the 305MB of the night's
recording from minidisc to computer in 5 or 6 minutes via USB.
3. "Synchro" mode might be a good way to record this data, since it
pauses the recording when no sound is present. When sound is
detected, the recorder starts a new track, with date and time stamp.
This third point has a couple of practical problems. Minidisc specs
limit the number of tracks to 255 per disc. (I have not seen if Hi-
MD raises this limit.) It's possible, even likely, that a 10 hour
recording would have more then 255 sound "incidents." That's one new
track every 2.35 minutes.
The second practical problem is that current Sony recorders will
do "Synchro" recording via the optical digital input only. So you'd
need an analog to digital converter between the bat detector and the
recorder, such as the Denecke AD-20 ($325). This adds significantly
to the liklihood that there would be some cabling or battery snafu.=20
But "synchro" recording would greatly improve the efficiency of the
data analysis.
Sharp minidisc recorders can do "synchro" recording using the analog
mic and line in. But Sharp has not announced plans to sell a Hi-MD
recorder yet. And Sharp recorders lack the date and time stamp on
each track. That information might be important in subsequent
analysis.
--oryoki
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