Download Audacity from their website and install it. Now download rive.mp3 file and run Audacity. From the main menu of Audacity, choose File | Open, locate river.mp3 file, and click Open. As you see, this audio file is 32 bit with 48 kHZ sample rate and 2 channels (stereo file). For our purposes, a 16 bit audio file with 44.1 kHz is sufficient. Moreover, If you use 2 channels for audio file, Vanda Engine won’t be able to calculate 3D sound based on the parameters of source and listener. Due to that, we have to convert our stereo file to mono file.