CloudACM – Page 38 – Autonomous Computational Machines

Ultrasonic SoX

November 6, 2017 Patrick Gilfeather

This post will be quick and to the point. We’ll be using SoX to bring high frequency audio, commonly referred to as ultrasound, down to a range that can be heard. First thing I did to validate the process was generate an ultrasonic data file using Audacity. The problem with the standard 44.1k sampling rate is ultrasound frequencies will be dropped. I created my data files with a sampling rate of 192k. play “/home/local/Desktop/Ultrasound/Audacity192k_33khz.wav” Playing audio from this sample is…

Infrasound processing with SoX

October 30, 2017 Patrick Gilfeather

In this post I’ll cover how to use SoX to make low frequency sounds audible in a range that can be listened to. Infrasound is a low frequency sound wave that ranges from 20 hertz down to .1 hertz. Monitoring audio frequencies in this range is typically done to detect seismic activity that is caused either by nature or artificially, https://www.isla.hawaii.edu/sounds/ocean-sounds/. I have a sample of video that was shot with a Mobius camera. The audio range of the camera’s…

Noise Filtering with SoX

October 23, 2017 Patrick Gilfeather

In this post I’ll cover how to remove noise in an audio file using SoX. I’ll be using a Raspberry Pi which does not have an audio input by default. To get audio, I used an simple USB audio microphone to capture audio. The OS I’m running on my Pi is Ubuntu Mate and there was no need for anything to get the microphone to run. Once it was plugged in, I ran this command to view the properties of…