Nika Aldrich wrote:The problem is realized in that while going through these digital gyrations and utilizing digital tools to amplify the signal as much as possible, both during mixing and during mastering, the ‘peak value’ of the sample points is closely watched to ensure that it does not get to full scale. Since, the peak meters in said DAW and digital mixing systems are inaccurate, and do not actually indicate the peak values of the resulting waveform, the result is that while the samples themselves do not exceed full scale, and are carefully monitored to insure this, the resulting waveforms represented by the samples may exceed full scale throughout any standard CD!
While the digital mixing system is not clipping the music or distorting the music, the digital to analog converters that have the task of recreating the audio through digital reconstruction filters are clipping repeatedly throughout most CDs on the market. The result is that most CDs and DVDs end up distorting with regularity when they are asked to reconstruct and play back audio that appears to be completely ‘legal’ because not a single sample actually clipped.
In a recent paper [Nielsen 2003], seven consumer CD players were subjected to tests designed to analyze their ability to reproduce and reconstruct signal levels above full scale (0dBFS). All of the players experienced difficultly dealing with signal levels this high, further showing that, while all of the samples can be legal, the level can still be hotter than is legal the result being that a CD player can be unable to reproduce the audio accurately.
It is nearly certain that this constant barrage of distortion that we, the consumers, are hearing on compressed and mastered CDs contributes to the ‘digital harshness’ still reported by the more sensitive audiophiles in the music industry. According to industry insiders, not a single off-the-shelf digital to analog converter chip made today can accurately pass a signal wherein the samples are under full scale but the waveform that they represent exceeds full scale. Only a few high end converters in the professional market can do this. This means that the preponderance of consumer (and professional audio) playback equipment is not designed to deal with these ‘hotter than full scale’ signal levels.
This makes sense, particularly if most everything in the file in question is compressed to near-zero. But if that is not the case, I tend to agree with Luke on this one.
I've taken the Henry Cow tracks, converted them to 32-bit floating point, took the gain all the way up to -0.1 dB peak on each track, then saved as 16-bit files, using POW-r 3 dither. I figured I'd put the number crunching and dithering through its paces.
How do they sound? They sound just fine to me; better than than the thin-sounding (and, yes, slightly compressed) remastered CD. I haven't noticed any artifacts. (That doesn't mean they are not there; I just have yet to notice anything amiss!) As I said, the levels on this CD are ridiculously low. In fact, using the "bit usage" meter in Peak on the original 16-bit rips shows that most tracks only utilize 14 or 15 bits to begin with.
If you guys are interested in a blind listening test, I could easily make WAV samples of these files in their various stages. I can also make samples using all three different POW-r settings (I want to investigate this further).
Anyone up for a listening test?