kstuart
1000+ Head-Fier
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Originally Posted by Baldr /img/forum/go_quote.gif
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Back to the bits - I know of no DAC that decodes any kind of reality beyond 20 bits and those get really expensive (Like the Yggy). You can use two per channel and get 21 real, honest to God bits. The megaburrito filter's DSP chip runs at 32 bits - not that is any bragging right other than it puts the computational errors at least 12 bits below the rounded output of Yggy, 14 bits below the rounded output of Gumby, or 16 bits below the rounded output of Bimby.
Numbers for numbers sake are fairy tales translated into marketing.
All that is true.... and I am enjoying your "megaburrito" as I type this.
However, there are very good reasons for 24 bits in recording and consumer file formats, as explained by recording and mastering engineer Barry Diament (whose Bob Marley and Led Zeppelin CDs are still highly sought after):
In a 16-bit recording, one is making the most of all 16 bits when the signal is loudest -- at the top 6 dB of the possible levels (6.02 dB for those who want more precision). Now of course, with real music the signal is not always at the top of the level scale. In other words, not every part of the song is at the loudest point. Further, there are things in the background that are lower in level than things in the foreground. Instrumental harmonics (the things that differentiate a Steinway from a Baldwin or a Gibson from a Fender) are considerably lower in level and spatial cues (whether real or studio generated) are lower still. To put it into numbers, the harmonics might be 20 dB lower in level than the loudest sounds. Spatial cues might be 40 dB lower in level. (I'm just picking the numbers arbitrarily to illustrate the point.) With a 16-bit recording, those harmonics that are 20 dB lower in level will be encoded using about 13 bits, not 16. The spatial cues that are 40 dB lower in level will be encoded using about 10-bits, not 16. This accounts for the coarsening of the sound and thinning of instrumental harmonics many have notices with 16-bit audio since the beginning.
Now let's look at the resolution of the same items with a 24-bit recording. The harmonics, at -20 would be encoded using about 21 bits. The spatial cues, at -40 would use about 18 bits. Both still exhibiting more resolution than a full level 16-bit recording. So if you make the same recording at 16/44 and at 24/44, you'll find the complexity of instrumental harmonics much better preserved on the latter. Same with the spatial cues: where the 16-bit version defocuses the space, the 24-bit version makes the room boundaries clear and easy to hear by comparison.