SoX is a cross-platform command line utility that can convert various formats of computer audio files into other formats. It can also apply various effects to these sound files, and, as an added bonus, SoX can play and record audio files on most platforms.
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NirCmd is a small command-line utility that allows you to do some useful tasks without displaying a user interface. By running NirCmd with simple command-line options, or via a shortcut, you can decrease or increase the system volume, mute or unmute the system volume, speak the text currently in the clipboard or text file, change the default sound device, display a list of sound devices, change the volume of an app, change the display settings, turn off the monitor, open the door of a CD-ROM drive and more…
www.nirsoft.net/utils/nircmd
Command Reference
Change Default Sound Device
List Sound Devices
Change System Volume
Change App Volume
An extensible, multi-format audio conversion and tagging module for Windows PowerShell™
github.com/jherby2k/PowerShellAudio/releases
Primer
List of Cmdlets
Script Examples
Hydrogen Audio Forum
Hydrogen Audio Wiki
The Audio File 