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What is dynamic range and why does it matter?

  • Why can’t a nose be 12 inches long? Because then it’d be a foot. The world is full of bad jokes. In our hifi world it takes recorded dynamic range and 1’000-watt amplifiers to realize it. To get in on the joke so you can properly cry about it, let’s define this dynamic range as the difference between the quietest and loudest sound on a particular LP, CD or digital file. On this scale sounds can’t get louder than 0 because anything above no attenuation or max signal would constitute distortion. Instead we measure backward. If the loudest peak occurs at 0 and the quietest sound at -6dB, we call it 6dB of recorded dynamic range. It’s super basic.

    Mind you, this is no fixed measure of loudness. We’re in control of where we set 0 aka full throttle. If we’re headbangers, we might call it 110dB before the police shut us down. If we’re softies, we might set our hifi’s volume so 0 equals 75dB. For the banger the file will never play at less than 104dB as six decibels down from full tilt. It’s called serious noise pollution. For the softie it’ll be 69dB. That’s a huge difference in loudness. Yet for both the recorded dynamic range remains unchanged. It could be no other way. It’s why we call it ‘recorded’ dynamic range. It’s embedded on each recording as the mastering engineer has locked it in.

    Incidentally, the loudest peak of a recording needn’t hit 0. Some recordings don’t exceed -10dB. If their recorded dynamic range is high – let’s call it 30dB like a good ECM recording – our playback SPL will flutter between -40dB and – 10dB. For argument’s sake, let’s call the medium value -25dB. That’s where most of the musical action happens. It’s the majority SPL.

    Now compare that to a hot recording of just 4dB of dynamic range which was mastered to butt right up against zero. It takes no genius to realize that if we set our hifi’s volume control so our dynamically eviscerated always-loud digital file plays at our desired SPL, once we switch to the ECM recording, we’ll have to crank up our volume control by quite a bit to get equivalent SPL.

    The easiest way to illustrate what recorded dynamic range looks like is to take three screenshots of Audirvana’s software player. The first is from the latest Strunz & Farah album. It’s one solid black bar without any wiggle room. There’s essentially no dynamic range at all when the very word ‘range’ implies variability or differences. If Audirvana’s display scale were larger, perhaps we’d see some micro wiggles? As it is, we see none.

    Everything is equally loud all the time. It’s like a redacted Secret Service document. All the vital bits are blocked out. It’s obnoxious, boring, exhausting and musically bland. It shuts down an entire dimension of artistic expression. Being a great musician isn’t just about playing the right notes at the right time and in perfect pitch. It’s about how a melodic arc is being drawn across varying dynamic tension; about how counter-beats in a groove set accents or inflections. When that dynamic dimension shuts down, it’s the musical equivalent of a perfectly monotone presenter who speaks without any inflection whatsoever. It’s worse than robotic. Pity the poor students attending his lecture. They’re supposed to learn something to require top attention. Yet their entire auditory mechanism has shut down just to avoid the ghastly human drone with the fancy letters behind his name.

    Now check out the second album from The Ayoub Sisters. Whilst we do get a block of very little variability before the final segment, we see a lot of instances where the signal is far less than full throttle.

    Before you object that such “high-brow” fare is only for weird moonies whereas you listen to proper stuff, check out the opening track of DJ composer/producer Mercan Dede’s Dünya album which mixes acoustic instruments with synths, loops and effects and places them inside very sophisticated artificial soundstages. This shows proper recorded dynamic range despite including plenty of electronica.

    Much hoarse shit gets shovelled into Gucchi bags about high-resolution recordings which “finally offer playback at real-life dynamic range”. In theory, the argument is rosy indeed. In practice, it’s sharp thorns all the way when heavy dynamic compression during particularly the commercial mastering process squashes dynamic range to death. I own one commercial CD from Tony Minasian of Tonian Labs whose recorded dynamic range is better than 50dB! It’s a perfectly ordinary CD defined by the very same 16-bit/44.1kHz standard as any other. The difference is that Tony Minasian applied zero dynamic compression or EQ during recording or mastering. Yet it’s just two LA session musicians playing around whilst traversing more loudness difference terrain than the majority of classical symphonic recordings manage.

    Don’t blame the medium. Blame its users in the recording/mastering studios. Until the day that all commercial 16-bit/44.1kHz recordings feature 50dB or better recorded dynamic range as they’re perfectly capable of; until the day that we as the audience clamour for a lot more… there’s no reason for higher resolution. The CD medium is perfectly capable. It’s the recording and mastering engineers who don’t tap its potential because their clients want “to sound louder”. Now they demand dynamic compression. In business whoever pays us is right. When a band or soloist or label hire a mastering lab, the latter’s professional do as they’re told. It’s how they put food on the table. It’s no more complicated than that.

    Well, there’s just a tiny bit extra for our purposes today.

    Opposing recorded dynamic range is ambient noise as the standing background noise of our listening room. In a busy inner city with poor window seals, it could be 45dB, and during heavy traffic even higher. In a quiet rural house down a few miles of pothole-poxed dirt road, it could be as low as 30dB. In a recording studio treated for top acoustic isolation, with a main door that closes tight like a bank vault, it might still get lower by just a bit. Even with 2nd-grade math, we appreciate that our inner-city listener suffers an extra 15dB of background noise. It means he/she will have to set playback levels higher to ensure that the quietest recorded passage won’t fall below their ambient noise to get swallowed up by it.

    True, ambient noise is no steady state. It fluctuates. A car goes by and during its brief passage, our ambient noise goes up. Then it lowers again. But it’s certainly relevant that the lower our background noise is, the more subdued we can set our playback levels and still hear everything, even the quietest passages. Another factor is personal hearing sensitivity/loss. What’s barely loud enough for one person to be enjoyable could be intolerably loud to another. These factors all pool into where people set their volume controls. Listening loud over prolonged periods desensitizes our hearing. Now we have to listen progressively louder to get any satisfaction. Finally, it’s time for a hearing aid. Hurray.

    What about the poor joke I promised going in? I have more than one. There’s believing that CD and its digital file equivalents are inadequate to chase hi-rez recordings instead. There’s conflating recorded dynamic range with loudness to think that since a live rock concert might output 110-120dB levels, such recordings must have high dynamic range. Wrong. They tend to be some of the worst extremists of the always-loud jihadists. It’s an even poorer joke to apply the word ‘realistic’ to playing back a rock concert recording set to 110dB peaks in a 4x5m listening room. Any musician worth his or her salt adapts how loud they play—or sets their sound reinforcement kit accordingly—to the venue they find themselves in. Small room, lower volume. It’s kindergarten stuff.

    Anything else is barbaric and bad for our health. The image of the grizzled long-haired rocker with his deep liver lines and severe hearing loss is no joke. It’s sad that the sensory faculty at the core of his art got this damaged in the very pursuit of the art. What is a bad joke again is that the Tony Minasian CD is of music I don’t much listen to. Who really cares how well it is recorded? Give me the Alphorn quartet and Swiss yodler. Meanwhile, in its present state of flatlined dynamic range, the Strunz & Farah CD I really wanted to hear is unlistenable excrement.

    Time for a really bad joke to close out proper: what did the fish say when he ran into a wall? Dam.

    P.S.: And then the dyslexic man walked into a bra. Did you notice the Easter egg? Of the three sample tracks above, two were CD quality, one a 24/88.2 high-resolution file. Guess which one has the redacted solid bar for its dynamic range? The latter. You can be high-res and dynamically suffocated; or ‘normal’ and dynamically liberated. One has nothing to do with the other.

    Ready for one more bad joke? How do you create holy water? You boil the hell out of it.

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    Written by Srajan

    Srajan is the owner and publisher of 6moons. He used to play clarinet at the conservatory. Later he worked in audio retail, then marketing for three different hifi manufacturers. Writing about hifi and music came next, then launching his own mag. Today he lives with his wife Ivette and Chai the Bengal cat in a tiny village overlooking the estuary of Ireland’s Shannon river at County Clare’s border with County Kerry. Srajan derives his income from the ad revenues of 6moons and his contributions to Darko.Audio.

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