This deranged-lofi-noise-fest was extracted directly from my voicemail. I suspect that it was left by the same person who has left other strange voicemails for me in the past. In this case I have learned that the sound source was a guitar being played with a mobile phone as a slide while the same phone was leaving me a message. So, while the guitar produced the sound, the mobile phone was a slide, a microphone, and a recording device all in one.