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Post by slowscape on Jan 2, 2021 19:26:35 GMT
This was a chat we were having over on the discord, and I thought it would be something good for the whole community so I'm putting it here.
No this isn't AEM specific, but I think it's related to what we're all doing on our AEM's, especially when we are sharing our music with the community/world.
The video also isn't a tutorial. It's more of a talk about the history of mastering and how it changed with the medium intended for release. It's interesting, and important, because everything has changed now that streaming is the primary method of sharing music, whether that be through youtube, soundcloud, bandcamp, or spotify.
Basically all of these services normalize all music they stream by "loudness". So when we master, or even record that is a concept to keep in mind.
I'm not trained in this, but found the talk interesting. Feel free to chime in with your own insights!
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Post by MaxRichardson97 on Jan 2, 2021 23:55:09 GMT
I always find Paul White's advice on mastering to be great. The Producer's Manual is a great read, loads of good info!
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Lugia
Wiki Editors
Ridiculously busy...ish.
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Post by Lugia on Jan 3, 2021 3:08:34 GMT
One other thing that HAS to be mentioned in mastering for compressed distro is aliasing. And this applies to ALL 44.1 or 48 kHz digital recording, but it really gets stretched when you take a WAV that has a lot of high-end content and then expect that to work just fine when it's been converted.
Aliasing in digital audio doesn't necessarily produce a clearly-audible result. Instead, it winds up generating a lot of high-partial junk that we perceive as "brittleness". And there's a fairly easy way to actually use this to your advantage!
When tracking your final mix, try adding a NONRESONANT lowpass filter to each channel of the stereo bus, and then set this somewhere between 12 and 16 kHz...it varies depending on content and filter. What this does is that it rolls off the very high partials...but in a way you wouldn't expect. Instead of anything being audible being filtered out, what you're actually doing here is to attenuate the very top end in a "slope" so that there's just a TINY amount of that aliasing still coming through. By doing that, we perceive the result as having a certain "shimmer" to it, which is actually quite pleasant as it adds a tiny touch of presence in the audible high end.
So what's going on with that? Well, given that filter rolloff curves are factored in dB per octave, by setting the filter to that range, the FULL rolloff never gets achieved before the A-D conversion. Instead, the highest partials are still being allowed to alias...but at a much lower level, so the aliasing then drops to something of a subliminal level where we don't necessarily HEAR it, but it does add something. Just in this case, that "something" isn't prone to degrade the sound, but the "shimmer" happens which actually gives more stereo field definition, presence to your higher-pitched content, etc.
A synth filter, btw, isn't the right thing to use here. I use a pair of Krohn-hite 330M bandpass filters...the highpass is set to around 2 Hz as a final DC offset stripper, and the lowpass as noted above. These have 11 stages of active 12AX7 and 12AU7 tube-driven level balancing, so they ALSO add some of that nice tube nonlinearity to the sound. But ANY good scientific-grade filter set will be just fine; I'd actually recommend the Krohn-hite 3550 for this, since it's also got some worthwhile uses besides this.
Oh, yeah...what about brickwall filtering, you ask? Well, given that it's much like what it sounds like (a filter that sharply cuts EVERYTHING, typically at around 21 kHz or thereabouts), it doesn't do that dB-per-octave soft rolloff...so, yeah, more brittleness.
One last thing: www.kvraudio.com/product/codec-toolbox-by-sonnox That's a fairly inexpensive codec auditioner, which lets you feed your result through several typical compression algorithms so that you can treat those just like you might check your mix on several different speakers. If there's anything that Bandcamp et al is going to screw up, you can screw that up BEFORE you get it to Bandcamp and see if their codecs are going to wreck your sound, then you can fix things in your mix chain to correct these. It's a pretty useful checker, in short! |
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Post by robertlanger on Jan 3, 2021 8:45:52 GMT
Thanks for bringing up this topic; I'm sure it's interesting for many of us - including me ;-)
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cpruby
Junior Member
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Post by cpruby on Jan 3, 2021 10:00:26 GMT
Very interesting video. The part that stood out to me, which I feel he brushed past too quickly, was that "oh there is a way to calculate the loudness value, and you all know that" and then talks about looking at intensity levels. I wanted to know more about how loudness is determined.
Because it sounded like these different services use these calculations and then knock it down x dB to even the playing field across tracks. And if its on a per track basis, you potentially could not use the dynamics of an album (and the album as a product is another topic with streaming). What is this formula? If anyone has a link to it, please post it!
In the world of hearing science there's intensity (physically how much energy is pushing through the air, the typical unit used is dB Sound Pressure Level [SPL]) and loudness (how your brain interprets how...loud...a sound is, and the units used frequently are sones and phons). They have a correlation, which he mentions in the video and there are some points of departure. An example, a sine wave (a single frequency) will be perceived as softer than white noise (all frequencies at equal value) when presented at the same intensity.
I teach an undergraduate level course in hearing science, so this is quite interesting.
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Post by spacedog on Jan 3, 2021 10:35:05 GMT
You can do a LOT worse than to use Airwindows Ultrasonic for your anti-aliasing duties, and it's free. The interface is somewhat stark, but it gets the job done. Here are some details:
There a less CPU-hungry version built into every channel of his Console, which provides some really interesting interaction between channels at the mixing stage, details here:
There are quite a few other interesting utilities in his collection, but I'll let you discover which ones for yourselves  |
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Post by spacedog on Jan 3, 2021 10:53:58 GMT
Oh yes, and loudness metering is pretty important when you're trying to limbo under the "compression bar" set by these various streaming sites, this one is both free and pretty good: |
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Post by slowscape on Jan 4, 2021 17:39:23 GMT
spacedog Thank you for that loudness tool!!
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Post by keurslagerkurt on Jan 5, 2021 13:51:52 GMT
Very interesting talk, thanks for sharing!
And now I'm sure I'll never be a mastering engineer: the moment he says all the limiters sound completely different while I hear no difference at all haha
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Post by slowscape on Jan 7, 2021 21:36:04 GMT
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Post by lukylutte on Jan 8, 2021 7:02:29 GMT
Really interesting stuff! Wouldn't mind if it was 1h longer...
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namke
wonkystuff
electronics and sound, what's not to like?!
Posts: 686
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Post by namke on Jan 8, 2021 10:07:11 GMT
Hmm, I bought this book (Mastering Audio by Bob Katz) some years ago, but never quite finished reading it. Looks like it is out of date!! I think I preferred it when human beings chose playlists based on personal choice, rather than algorithms based on perceived loudness  |
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Post by martynaudio on Jan 8, 2021 14:54:35 GMT
thanks for sharing Slo! definitely worth a watch |
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Lugia
Wiki Editors
Ridiculously busy...ish.
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Post by Lugia on Jan 10, 2021 5:19:08 GMT
Yep...I'd say that if you're doing anything for "public consumption", it's very worthwhile to get a VST that can give you LUFS metering. Mine is hardware (tc Clarity M Stereo) but there's plenty of software options out there, too.
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