Dynamic Range Day

I first became aware of this day via a twitter post by Steve Moyes. The idea behind this twitter tag: to raise awareness for the negative effects of the so-called loudness war: the tendency of CD producers to make the CDs in a way so they sound louder and louder when played back at the same volume level.

The concept for the listener/music fan is basically completely ununderstandable: if you want it to be louder, turn up the volume on your stereo. I will not address them in this post – rather I’m targeting this multitude of people who are producing their own music in their home studios, and how to avoid to get caught up in this dangerous trend.

I will completely go past explaining why this loudness war is so bad – as a prime example, read it up on the website of multi-grammy-winning mastering engineer Bob Katz (check out the media-articles section).  However, I will summarize the relevant parts of his two-part article “level practises” (part 1, part 2):

If you’re mixing or mastering your stuff at home, before you even start, calibrate your speakers. Now, what does that mean?

The idea is to maintain a direct correlation between the audio on your computer in those wav files and the sound pressure levels you’re hearing in your home studio. Basically, it means that a specific waveform will be heard at a specific audio level by you in a reproducible way (which is also reproducible by other people with calibrated speakers listening to the exact same file).

There’s the so-called “magic of 83”, described in Bob Katz’s article. In a lot of experiments, the AES had discovered that the most pleasant level for attentive listening is for a “forte” passage (i.e. louder part of a piece, in pop/rock terminology e.g. the chorus) to be at 83dB SPL.

Now what Katz simply states is that you calibrate your speakers so at a level that’s forte, you’ll listen at 83dB.

There are two effects resulting from this: first of all, the so-called equal loudness contour of the human auditory system at that level has the highest degree of flatness. At lower volumes, we tend to perceive frequencies around 800Hz and 2-3kHz much louder than everything else (which, obviously, evolution designed in a way so we are able to understand human speech very well). The second effect is that 83dB is actually quite loud: a table on wikipedia defines that as the equivalent of traffic on a busy road at 10m distance. For comparison, a normal conversation is at 40-60dB, and with the “6dB is double as loud” approx. you can do the math: this 83dB level is 33dB or around 35 times as loud as a normal conversation! Still, you’re still very safe from the region where hearing damage can occur, even with prolonged exposure.

I will not go into the exact details how to calibrate your speakers, only so much: you need a sound source that can generate a -20dBFS C-weighted pink noise (in other words, your run-of-the-mill audio editor), a SPL meter or a calibrated microphone (e.g. this one) with either a frequency analyzer or again your computer with a analyzer software like this.

Now here is what Bob Katz has to say: for mastering audiophile stuff, calibrate the 83dB SPL to a -20dBFS pink noise. For normal rock/pop, calibrate it to a -14dBFS pink noise. Obviously, when mixing turn up your listening volume by at least 6dB.

Ok, done with it? Now, assuming you calibrated with the -14dBFS signal (this is what Katz calls “K-14”), load a contemporary rock/pop song into your audio editor, press play AND IMMEDIATELY PRESS YOUR HANDS FIRMLY AGAINST YOUR EARS!

Now you can start turning down the (dB-scaled) level adjustment in your audio editor, until you are safe to remove your hands from your ears. What’s that reading on the level adjustment dial now – if the track is playing loud, but not overtly so? I guess it’s in the -6 to -8dB region. This is basically by how much this song is mastered too loud.

Now for a change, take a track from sections 1 or 2 of Bob Katz’s Honor Roll, and do the same. You will find that you don’t have to turn it down quite as much (in fact, for albums like Joe Jackson’s “Body and Soul”, you may even want to turn it up). (self marketing starts here: you may also take a track from one of my recent albums).

Now you’re already done! And for all the future, mark these level settings on your amp/active speaker, and whenever you’re doing a mastering job, set them there. And if it’s too loud – turn the volume of the track down, or remove compression. It’s as simple as that!

Ok, now don’t thank me, just tell your listeners to thank me (and #dynamicrangeday, and Bob Katz), because if you followed these instructions, I bet your following releases will sound more open, more punchy (yes! they actually do that!) and all in all much better.

Have a nice evening,

Rainer

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