cliveb;208309 Wrote: > ... But I don't know whether the Squeezebox does this - I'll try an > experiment and report back. OK, I've done a quick experiment. I prepared a short FLAC file with a deliberately low average volume and with a short section that peaks at 0dB. (The Replaygain value for this file is +20.18dB, and it includes the necessary peak tags as well). Playing this file through Foobar2000 (with the appropriate options active) demonstrated that the gain is scaled back to avoid clipping.
Playing it through an SB2 (firmware version 69) resulted in clipping. I therefore downloaded the latest Slimserver (6.5.2-12047) to check this had not changed. The clipping still happens with firmware version 81. Therefore we can conclude that the Squeezebox does NOT take notice of the Replaygain peak tags. I also tried reducing the SB2 volume to 2 (out of 100, which means it is at about -49dB). The clipping still occured. Therefore we can also conclude that the Replaygain adjustment is applied to the raw data stream before the digital volume control is applied. (I did not try the test on my Transporter, as I didn't want to risk the possible consequences of extreme clipping on my main speakers). I think that the way it should work is as follows: 1. Certainly, the peak tag should be honoured so that clipping cannot be introduced. The fact that it is not should be considered a bug. 2. A "nice to have" would be for the digital volume control setting to be considered in the calculation. For example, suppose the Replaygain value for a track is +6dB and the peak value is 0dB. A simplistic honouring of the peak tag would result in no gain being applied. But if the Squeezebox's digital volume control is currently set to -6dB, then the overall volume could be set to 0dB, thus achieving the desired loudness equalisation. (And if the SB volume is set to -9dB, the overall volume should be -3dB, etc). Of course, this refinement should only happen if the digital output is set as variable. I've searched Bugzilla looking to see if this has already been reported, and couldn't find it. But before I do add a bug report, I'd like to hear the views of others. -- 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=35999 _______________________________________________ discuss mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/discuss
