[Name] soundLevel [Type] signed ("+" or "-") CSS2 numbers immediately followed by "dB" [Required] No [Default Value] +0.0dB [Description] 
Decibel values are interpreted as a ratio of the squares of the new signal amplitude (a1) and the current amplitude (a0) and are defined in terms of dB: soundLevel(dB) = 20 log10 (a1 / a0) A setting of a large negative value effectively plays the media silently. A value of '-6.0dB' will play the media at approximately half the amplitude of its current signal amplitude. Similarly, a value of '+6.0dB' will play the media at approximately twice the amplitude of its current signal amplitude (subject to hardware limitations). The absolute sound level of media perceived is further subject to system volume settings, which cannot be controlled with this attribute.