I’m hoping that yesterday’s post about what is definitely NOT high-resolution audio has sunk in. Some readers felt the need to push back and would like analog tape to be considered high-resolution. But as I tried to explain in my responses to the comments, just because something is preferred doesn’t magically change its specifications or capabilities. I’m fine with analog tape as a format…but it does belong in the standard resolution category. Admittedly, this is going to be the toughest challenge among professional engineers and producers. I fully expect that they will stick to their beliefs that analog tape best represents music when recorded. Again, it’s simply a flavor thing…but not high-resolution.
Today, I’m continuing with the quest for a suitable definition for high-resolution audio. We know what it is not. Now let me share some examples of what is definitely high-resolution!
There’s also the issue of intentions and goals. Clearly, not every artist, engineer and producer are trying to create and release high-resolution music. But I believe it would be preferable to adopt higher sampling rates and longer word lengths during the production process so that there is at least the possibility that the project could include an “audiophile” version. A few artists have done this and I know many original digital productions are done at 88.2/96 and 24-bits. Very few are done at 192 kHz and virtually none are recorded at 384 kHz (there is absolutely no need to go this far…other than impressing people with big numbers).
So here’s my list of recording formats that are definitely high-resolution. [NOTE: These are RECORDING formats NOT delivery formats! A project must have been captured at the time of the original session using high-res equipment for it to be considered high-resolution. Transfers of older non-high-resolution materials will remain standard resolution despite the best efforts of many others in the business.]:
1. 88.2/96 kHz/24-bit PCM – This level of digital recording should be adopted as the minimum standard for true high-resolution recording. The dynamic range of 24-bits (within a production environment that uses many more bits during processing) is more than enough to capture the entire range of amplitudes human hearing is likely to be submitted to (130-140 dB) AND it guarantees that our traditional hearing range is captured as well as the potential (and debatable) next octave.
2. 176.4/192 kHz/24-bit PCM – Despite the protestations of other experts, moving to these sample rates does make sense for audio archiving. I plan to capture analog masters at 192 kHz if provided analog two-channel stereo tapes from the major labels because it means that the PCM digital masters I create will have plenty of specification “margin” to get everything that came from the tape. I personally believe this is overkill but for archiving a classical analog master…no problem. In reality, 96 kHz/24-bits is enough.
3. 352.8/384 kHz/24/32-bits PCM – Some are calling this “ultra high-resolution audio”. I call it marketing nonsense. There is no reason to run capture systems at this rate. We don’t have microphones and speakers that extend beyond 40-50 kHz so why would anyone push the sampling rate past 96 or 192 kHz? It makes no sense.
4. 2.8 |5.6| 11.2 MHz DSD – As all of you know, I have major reservations about this “so-called” 1-bit encoding scheme especially when it comes to producing products natively. But it’s in the marketplace and if used to capture music during an original session, then it meets my specifications (especially if you get away from 2.8 MHz). The problem here is there are no tools to work natively with DSD at any sample rate thus requiring conversion to other formats.
5. 352.8 MHz 24/32-bit DXD – My friend Morten Lynberg at 2L uses DXD at this rate to capture his projects. He posted a notice about an upcoming session at the Berlin AES convention where he and others will discuss the merits of DXD/DSD vs. PCM. What isn’t as widely known as it should be is that DXD is really PCM by another name. Refer to No. 3 in this list…because DXD is actually ultra high-resolution PCM. SONY and Phillips like this format and 2L and others use it because it can be converted easily to all other flavors of PCM and DSD. And because it sounds like it’s similar to DSD, which it is not.
So there you have it. Another set of five formats that ARE DEFINITELY “high-resolution audio” if used during an original session. We know what HRA isn’t and we know it is…now, think about the downloads you can purchase from the usual suspects. Are they high-resolution or not?
There’s a definition in there somewhere.