Hi all,
I am really trying to figure out if I am hearing what I'm hearing.
I was trying to record some insects in the desert mountains of western Texa=
s
last month. I was using my Tascam DR-680 and a pair of inexpensive Studio
Projects C4 microphones in a mic stand. As a side note, they are decent
microphones for the price and I have been pretty happy with them overall fo=
r
the $350 per pair that I paid. They aren't as quiet as an AT 4022
(microphone-data.com reports -13dB-A for the AT4022, -16dB-A for Studio
Projects C4), but they are half the price, come with cardiod and omni heads=
,
and are quiet enough for entry level nature recording in my limited
experience. But I digress.
While I was recording at a 48khz sampling rate, I noticed a bat swooping
down around my microphone probably attracted to my vehicle parking lights.
So, just for fun, I started recording at 192Khz even though my microphones
have a frequency response of 40Hz-20KHz. I didn't expect to record anythin=
g
other than crickets and a Common Poorwill or two.
However, when I pulled up the file in Audacity, I noticed a series of
clearly defined calls somewhere between 40Khz and 50Khz. Here's a screen
shot of the 0.6 seconds of the spectrogram (I am just looking at the right
track for simplicity) -
http://www.pbase.com/sandboa/image/155987370
I then slowed it down to 10% of the original speed to hear what I was seein=
g
and this was the result (slowing it down seems to make a lot of hiss that
isn't audible in the original recording) -
https://soundcloud.com/sandboa/ultrasonic-bat-recording-from-non-ultrasonic=
-
mic
My questions are:
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