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Example Recordings

A project log for High Performance Audio ADC for Machine Learning

A system that can record high quality audio (24 bit, 48kHz 120db SNR) continuously and unattended outdoors.

filip-mulierFilip Mulier 10/10/2021 at 13:410 Comments

Here are two example recordings.  The first one is a complete recording done over 20 hours, with an audio file for each hour.  The files are recorded using the opus compression standard with a high quality setting.  The recording was done in April 2021 during the pandemic shutdown, 5 miles away from major highways in northern Wisconsin near a small field.  There are some human sounds, but the majority are natural.  The ADC gain is 50dB 30dB analog and 20dB digital.  At some point I want to calibrate the full audio path (mic - ADC Gain - sample value) to be able to provide the rough absolute sound pressure in the signal.

Early Spring in a Small Field 2021-04-09

The second recording was 14 hours recorded using flac (lossless) near a bog overnight in northern Wisconsin on June 13, 2021.  I made 2 files available because they are large (600MB per hour).  The ADC gain is 57db, 30dB analog and 27dB digital.  I ran these through my ML model and identified the timings of the detected bird calls with highest predicted probabilities in the recordings:

File: Marsh 2021-06-13 4:04:55am central time

Eastern Wood Pewee (t=1771.57)

White-breasted Wood-Wren (t=1632.63)

Veery (t=2182.36), and a Common Loon (t=276.05)

I hear some bullfrogs too, but the AI model only handles birds.

File: March 2021-06-13 5:04:55 AM central time

Eastern Wood Pewee (t=306.57)

Black Capped Chickadee (t=3407.63)

Veery (t=964.47)

Great Crested Flycatcher (t=575.00)

Blue Jay (t=1389.47)

Common Loon (t=3544.73)

and possibly a Scarlet Tanager (t=419.21)

I hear Trumpeter Swans too, but they are faint.

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