An inflatable mattress having an inflated torso support pad, a first leg extending out from a first portion of the inflated torso support pad, and a second leg spaced from the first leg and extending out from a second portion of the inflated torso support pad. In addition, the present invention provides novel pharmaceutical compounds of Formula I, including the pharmaceutically acceptable salts thereof, as well as pharmaceutical compositions which comprise as an active ingredient a compound of Formula I. The system preferably includes one or more user-carried portable audio capture devices that employ a microphone, analog to digital converter, signal processor, and memory to store samples of ambient audio or audio features calculated from the audio. Synchronized AB switching during playback of various encoded audio signals allows the sound engineer to detect nuances in the sound characteristics of the various encoded audio signals.