The specifications of devices for digital audio, dazzled by numbers. What did not: and 32 and 44.1, and 48, and some even 384 kHz sampling frequency. I hope all your DAC accepts and understands, but from a good whether life arose this diversity? How these parameters are friendly with each other and who was your soundtrack in the original?
TEXT Jaroslav Godin
Nyquist theorem / Nyquist says that for more or less correct reconstruction of the analog signal after digitization requires the sampling frequency (ie sampling) twice as large as the original spectrum. Thus, the standard 44.1 kHz CD covers formal upper limit of human hearing is 20 kHz, leaving talk of the adequacy of these parameters for audiophile happiness later. It is better to talk about the devil and devils that lurk in the details.
Talk about lousy sound CD to DVD, and then the Blu-ray-players were induced not only by interference from video path. The fact that the video sources, and with them and audiopotroshki computers, which also went to the nuts from the demanding listener, guided by other service frequency — 48 kHz. When you receive from the CD PCM data with a parameter of 44.1 kHz will be recalculated under its iron and rails. Resampling an already resource-intensive activity. What threatens such alterations, and even more so at a frequency close to the non-multiple factor? If someone fiddling with editing images on your computer needs to know about the artifacts that occur when scaling an image — on a fine texture of moiré and other nasty stepped defect. To minimize damage in Photoshop using various smoothing filters. You are nothing like? So if what and enriched the final audio signal, only the new harmonics.
Wait a minute! And in what then was full soundtrack format before heading into the CD-circulation? Let’s try to guess. Come on, who went to the parish school, follow the fold decrease discreteness studio HD-Master — 24-bit / 96 kHz or 24-bit / 192 kHz. Yes, even to 384 kHz. See, again produced the same 48 kHz, both on computers and DVD! This glorious tradition was led further from the old digital DAT-80 tape recorders operating at this frequency, which, in turn, focused on industrial audiosempling 8 kHz telephone. And even today, many sound engineers prefer to write games in 24-bit / 48 kHz — still get good save hard disk space.
Thus, before reaching our ears, most commercial recordings crippled, not once. First, when mastering for CD-ROM, it is counting sampling studio source (48 or multiples in kHz) 44.1 — with all the ensuing inaccuracies. On reducing the bit depth from 24-bit to 16 I did not even stutter. Further reproducing apparatus lishenets undergoes reverse procedure — pumping roach with a view to get hold of the whale upsampling. And again, this inflatable whale raises questions, as the modern domestic upsampling DACs boast … in 96 or 192 kHz! Just only a few manufacturers use upsampling algorithms, multiple CD-ROM, ie, 88.2 and 176.4 kHz should be noted that this condition meets the specification SACD, whose sampling is exactly 64 times the 44.1 kHz a CD. This, incidentally, often helps to focus on modern resources such HDTracks.com, selling HD-files online. It is no secret that it is a significant part of the content previously released on DVD-Audio and SACD. So: as a rule, content taken from the DVD-A, with the parameters laid out 24/96 and from the SACD has a 24 / 88.2. Do not be mistaken.
So, what conclusions can be drawn from this sad part of the information? Well, where we can not return back into the minced meat grinder, will have to accept, as a Christian. And to acquire media lie close to the studio master. In one case, it would be faithfully executed hayrez in another — pervopress vinyl, and the third — the official release of the tape. But when the numbers are set by us should act wisely. For example, you hold the album in HD or rip vinyl record in 24 bit / 96 kHz, from which must make a compressed copy for portable or Car Audio. It should be recalled that in this case, you are not obligated to Red Book specification with its uncomfortable 44.1 kHz. Would it be original in 24/44 (there are also editions), or you need to MP3 rip compacted with Super Audio CD. In all other cases, please feel free from hayrezov MDE files sampled at 48 kHz, which will ensure the audio source played by any household — even iPods, though automotive «head.»
The main thing is to lower the sampling procedure was not only multiple but also performed in compliance with one condition. To put it simply does not forget about software resemplere (eg, SoX or SSRC), otherwise the direct mathematical impairing the original and will kill what little is left of it in a compressed file. Fortunately, good resemplery can now be found not only in paid digital audio editors, but also free utilities dBpoweramp or Foobar2000, whose multi-tasking well comforted after studying the activity of these products harmful canned music publishers indefinite shelf life.