Sound Resolution

Now what I’m going to tell you you already know back in some primitive part of your brain. Digital sound doesn’t sound as good as many analog recordings. Here’s why.

Digital sound is typically 44,100 samples per second. That sounds like a freakin lot of samples per second but it’s too low and that’s the problem. Really high quality sampling of sound takes place at 2,822,400 samples per second. This is known as SACD (Super Audio CD) developed by Sony and Philips. That’s 64 times greater than 44,100 samples per second. Currently, the best digital audio recordings have a sample rate twice as high as SACD. Or 128 times the typical 44,100 sample rate.

The problem is that CDs don’t hold enough information to be able to support SACD. You’d only get a couple of minutes or less of such audio on a CD. That is probably the historic rationale for commercial audio being typically 44,100 samples per second: the file sizes are not too big.

When I listen to typical digital audio, what I notice, if I crank it up–and I like to crank up music, typically–is that there’s no presence to the recordings. Some vinyl albums I had, when played on decent stereos–the stereos didn’t have to be top of the line, but they had to be OK–sounded pretty much ‘live’. They had presence. But digital audio, it can’t break through from the other side, as it were.

The reason why the sampling rate is important is this. You’ve seen wave representations of sounds. You know sound is waves of air–that’s what sound is. Well, the samples are points used to construct those waves. Imagine a curve. Any curve. Now imagine four points on that curve. Now draw straight lines from the first point to the second point to the third point to the fourth point. Those lines will look a little bit like the curve but not much, probably. You need more than four sample points so that when you draw lines from point to point, you get something that looks more like the original curve.

Similarly, the higher the audio sample rate, the better the audio software can figure out what the sound actually sounded like. Low sample rates result in sound that lacks the highest of subtleties we as feeling humans are able to infer from sound, and that’s its presence. All that info we pick up in live audio–how far away it is, the composition of what’s being struck, all the really subtle information that makes it ‘live’–is simply undetectable at lower sample rates.

So what? So what that presence isn’t a part of contemporary recorded sound experience? So what? What does it matter?

Well, it’s a question of whether it can break on through from the other side, isn’t it? What we get, currently, is a good idea of the sound. Not the mind blowing experience you really do get from great audio rendered in recordings with presence. Which explains why live performance is so esteemed these days over recorded sound.

As time goes by, digital audio will increase in the typical sample rate. Cuz all it takes is good technology to support it. Not impossible technology by any means. Eventually the typical digital audio sample rate will match and even surpass the good old days of vinyl.

But, in the meantime, we live in age of merely the idea of the audio in recorded sound. Play me something Platonic baby.

6 Responses to “Sound Resolution”

  • These criticisms of digital audio are nearly always based on anecdotal
    evidence. Suggested reading:
    http://www.aes.org/e-lib/browse.cfm?elib=14195
    or instead of paying the aes:
    http://c.wrzuta.pl/wo8536/848633c40022f8f4499160b0/0/jaes_v55_9_pg775.pdf

    (Thanks to linux audio user list for pointing this out)

  • Yok!:

    Man, you don’t seems to grasp the technology behind digital sound at all, you just regurgitating what everyone already know from press advertising of digital audio manufacture, which is not the way it works!
    Digital PCM encoding is just the first ring of a long chain in sound reproduction and it is by far not the most important!

  • HH:

    “Which explains why live performance is so esteemed these days over recorded sound.”

    This is a pretty radical conclusion. I think there are more factors drawing people into a live music environment! Embodied Sound, Community, Performance, and on and on and on!

  • This is in reply to James Morris’s post.

    “These criticisms of digital audio are nearly always based on anecdotal evidence.”

    Of course they are. They come out of the mouths of thousands of people who are relating their impressions of their experience. What would you expect? That a majority of peoples’ experiences were of double-blind experiments on the matter?

    The article James Morris referenced strongly suggests that there is no audible difference between good analog recordings played through certain types of analog systems and the same sound passed through a 44,100 samples per second filter played on other digital systems. Yet they say things like the following:

    “Though our tests failed to substantiate the claimed advantages of high-resolution encoding for two-channel audio, one trend became obvious very quickly and held up throughout our testing: virtually all of the SACD and DVD-A recordings sounded better than most CDs—sometimes much better.”

    They concede that these high-resolution recordings sound audibly better than CD-quality sound and go on to say, concerning the high-quality digital sound that “…engineers and producers are being given the freedom to produce recordings that sound as good as they can make them, without having to compress or equalize the signal to suit lesser systems and casual listening conditions.”

    They conclude the article by saying

    “The secret, for two-channel recordings at least, seems to lie not in the high-bit recording but in the high-bit market.”

    Which is to say that they expect that the difference they noted (but did not successfully quantify) is probably explainable not solely by the greater resolution of the SACD sound but also by the high-end systems used to play the SACD sound.

    Gentlemen. Why couldn’t similar issues—concerning primarily the systems used to play the sound—obtain between CD-quality sound and analog recordings on vinyl? I am merely speaking from experience, of course, in my impression that many great vinly recordings I’ve heard before conveyed more of a sense of physical presence than any digital music I’ve heard out of anything, but the experience is very strong. Now, whether this is not due to the deficiency of 44,100 sound but, instead, is a matter of compression and equalization “to suit lesser systems and casual listening conditions” or just problems with digital playback systems, I frankly do not know.

    In other words, perhaps it isn’t 44,100 sampling that is the problem, per se, but other factors.

    Yet the authors of the article I’ve cited do concede there is a noticeable difference in quality between 44,100 audio and SACD audio. The difference is a matter of both recording resolution and the quality of the playback systems.

    Are we to infer that the SACD systems sound better than the analog recordings and systems they used? We don’t know.

    Compression can be a problem for audio quality, of course, and this is quite a different issue from sampling resolution. So too can normalization do things to dynamic range.

    In conclusion, I may be incorrect to ascribe the differences I’ve heard simply to a matter of audio resolution—there are more factors at play—but that doesn’t mean the differences don’t exist.

    And thanks, James, for the challenging and useful reply.

  • Jim, fascinating exchange above: but aren’t all recordings irretrievably “absent”? That is what makes them “re”, no?

    No matter the specific technology, I’ve always been deeply skeptical of the obsessive search for acoustic fidelity, which purports to compensate for the inevitable absence of the carnal being who (somewhere else) made the sound. Yet it also baffles me why such absence would ever be heard as something lost, since the reproduction will pulsate with its own autonomous pleasures.

    How many times have I used the process of reproduction to juice up a dry fruit? Sometimes the entropy is far more pronounced in the original than in the recording! (Then there is the related question of the original already being pre-recorded, as more and more “meat voices” are shaped via the aping of reproductions, eg X Factor, etc., giving new meaning to Burroughs’ lucid comment, “nothing here but the recordings”.)

    Each sound technology engages the user’s senses — and sensibility — in a different way, with a significant effect on the quality of the listening experience. The act of dropping the needle onto the spinning disc has its own weirdly suggestive and stimulating resonance for my scratched up self, quite aside from any sound that then vibrates forth from my veteran Polk speakers.

    Meanwhile, teens are returning to vinyl in a big way, and I suspect this return has more to do with poesis than with a search for enhanced presence. At the risk of sounding like the B side to a McLuhan record : Needles dropped on turntables are mucho mas hot than scrolled files on Ipods. Two different temperatures for two different modulations within a shared absence.

    So interesting, your post, though, as I have been mulling what exactly it is that I sense is lost in digital radio — I will post soon, and try to think my way through some very murky intuitions.

    GW

  • I’ve been wondering, Gregory, how much my sense of the exquisite ‘thereness’ or ‘presence’ of some of those old vinyl records from my youth is simply fond remembrance of my youth and an enjoyment of music more than I do now, usually, it being newer and fresher then, to me. And I don’t have access to those old systems to compare them with my current one.

    Somewhat apart from the ‘memory theatre’ issue, with music, there’s a sensual element. Often, mp3′s and music from CD’s sounds subtly muffled or improperly accentuated in the bass range. Consequently, the experience can be somewhat muffled.

    I love great recorded audio. I’m more interested in it than in live performance, really. But it does depend on the signal coming through not too muffled or garbled and so on.

    And it seems there’s a lot of variation in how different digital system render audio, also. Macs and PCs, for instance, can make the same audio file sound fairly different.

    You’ve made some truly great recordings, Gregory. And they don’t really rely on the sensual element in the same way as some music. You are very good at using “the process of reproduction to juice up a dry fruit”. But, also, your work is so strong conceptually. The strong experience of your work results from that and also all the rest of the attention you give the other aspects of the work.

    I look forward to your thoughts on digital radio, Gregory.

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