liffy99;332522 Wrote: > Then this arbitrary level of 89db is touted around, but db is a relative > scale, so 89db compared to what ? It surely can't be 89db below full > output ! Or is it 89db above the -96db that might equate to the lower > threshold of Red Book resolution (which, presunably, could also be > represented as -7db). It's none of those. We'll get to what it actually is in a moment, but first a bit of background. Take a step back and consider what ReplayGain is trying to achieve. It's aiming to find a way to make the perceived loudness of various tracks and/or albums sound the same. In order to do that, it needs to choose a reference level. So what level should be chosen? There is no standard level in the audio industry, but there is in the movie industry. That standard is called SMPTE RP 200, and it states that a comfortable listening level is one whereby pink noise at -20dBFS RMS is played at 83dB SPL. ReplayGain originally used that level as its reference. In other words, after analysing the music track, it defined the volume change that would be required to make it sound the same loudness as pink noise at -20dB (and which, were it to then be played in a properly calibrated movie theatre, would be at 83dB SPL). Hence the use of the term "83dB" as the reference level.
After a while, actual implementations of ReplayGain gravitated towards aiming for 6dB higher than that, so we now have an unofficial "89dB" reference level. Since you're at liberty to set your playback volume control wherever you like, that 89dB figure is pretty meaningless. For the consumer of digitally-encoded music, it would make more sense to define the reference level as being relative to 0dBFS. On that scale, for a typical music signal, this reference level is about -24dBFS RMS. -- cliveb Transporter -> ATC SCM100A ------------------------------------------------------------------------ cliveb's Profile: http://forums.slimdevices.com/member.php?userid=348 View this thread: http://forums.slimdevices.com/showthread.php?t=51320 _______________________________________________ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
