Check this ELF- VLF Wav file first.

Then read this from Stephen’s Website:

“Recorded in a remote location by the Whitemud River in northwestern Alberta, Canada, about 45 miles/60 km north-west of Peace River, AB on 02 June 1996 at approx. 1030 UT (4.30 a.m. MDT).
‘Natural Radio’ describes naturally-occurring electromagnetic (radio) signals emanating from lightning storms, aurora (The Northern and Southern Lights), and most importantly, the Earth’s magnetic-field (the Magnetosphere).
This is a presentation of Earth’s natural radio emissions that occur in the extremely-low-frequency to very-low-frequency (ELF-VLF) radio spectrum–specifically, at AUDIO frequencies between approximately 100 to 10,000 cycles-per second (0.1 – 10 kHz).
Unlike sound waves which are vibrations of air molecules that our ears are sensitive to, natural radio waves as received at ground-level are vibrations of electric and magnetic energy (electromagnetic waves) which–though occurring at the same frequencies as sound–cannot be listened to without an audio-frequency ELF-VLF radio receiver to convert the natural radio signals directly into the same sound frequencies”

Lots more about this via this site, and yes, you need the CD.