Sound engineers and producers noticed long ago that if an average listener is given two identical recordings to listen to, they will choose the one that sounds louder. Therefore, recording a good mix is only half the job; you also need to carry out a number of operations on it to improve and tighten the sound—which is what this article is about. Some may think these are mere technicalities, but it is precisely such technicalities that make what is called Good Stuff =)
Note: the original article illustrated each step with screenshots (waveforms and plugin settings); these images are no longer available, so the descriptions below refer to them in words.
Dieb Audio mix before processing
The waveform of the mix before processing, mixed in Ableton, shows clearly that some tracks are quieter than others and that there is a significant increase in the signal level at the moments when the tracks are mixed. Note that the track levels during mixing have deliberately been lowered by -3 dB so that the signal does not exceed 0 dB even at the loudest moments. The periodic sections with greater amplitude are precisely the louder parts, when two tracks are mixed—that is, playing together.
Dieb Audio mix after mastering
This is the same mix some time later =), after passing through Wavelab and plugins. Now all the tracks are now louder, and the volume differences between tracks and at the moments when they are mixed have disappeared. This is a genuine Radio Version: dense and loud.
You have surely heard that the purpose of mastering is to prepare a track for recording onto a medium; in this case, the recording is in mp3/192kbps/stereo format. Why 192kbps in particular? We think this bitrate offers the optimal balance between size and quality. Size is very important! Those who download and listen to mixes are unlikely to tell the difference between 320kbps and 192kbps, while the size—and consequently the download time—will differ considerably =)
What happens to a 32-bit Wave file when it is converted to MP3 at low bitrates? Once this question is answered, it immediately becomes clear what needs to be done during mastering. The point is that, during lossy compression (into MP3 format), the track loses some of its high frequencies and becomes duller; this can be viewed with some kind of spectrum analyzer, for example the analyzer in Wavelab. So it is clear that the loss of high frequencies needs to be compensated for. I can immediately suggest three options for this: EQ, Multiband, and Exciter/Enhancer. EQ correction is obviously not an option; this kind of processing sounds, to put it mildly, unnatural. Of the remaining two, we settled on Multiband—that is, processing with a multiband compressor.
Previously, we used Waves’ Linear Phase EQ (a linear-phase equalizer), LinEQ Lowband, in the mastering chain to cleanly cut all infrabass frequencies (from 25–30 Hz). But now I strongly doubt whether this action is appropriate. Not long ago, Implex asked an interesting question about the difference between ordinary and linear-phase equalizers. I was unable to study the matter in detail right away—it turns out to be quite a substantial article—but we have already drawn a few conclusions. We compared a short impulse after processing with Waves LinEQ Lowband and with the “fruity” FL Parametric EQ 2.
What did we see? The cool Waves linear-phase equalizer produces oscillations =)—sine waves positioned on either side of the impulse; in other words, the signal becomes blurred, and by ear it sounds absolutely terrible, reminiscent of a flanger. Therefore, I think it should not be used for mastering mixes, although I may be mistaken—try it and listen.
Next in the master chain comes Waves C4, a multiband compressor. Here is the general idea of how to set it up to compensate for the loss of high frequencies. Do not take this literally or copy the numbers; I adjusted it simply to show the direction in which to work.
Once you have set up the multiband compressor, the mix should already sound much better than with the bypass button pressed (all processing turned off). Before the compressor, you can use an exciter—for example, the one in the Ozone plugin (it is better to turn off everything else it contains)—but only very slightly, so that it remains barely perceptible. And one more thing: do not increase the volume at this stage!
Top mastering engineers also advise additionally compressing the mix with a low threshold and a low compression ratio (figures of up to 1.15–1.25 are mentioned) to gain an extra decibel. A specialized compressor such as Voxengo Polysquasher is ideal for this kind of processing.
When setting up Polysquasher, pay attention to the Side HP control: this is a filter that cuts the signal being fed to the control channel. In this case, the compressor will respond only to the signal starting at 120 Hz. This is done to avoid the “pumping” effect, which is especially noticeable with these settings: when the bass drum hits, the entire mix “sinks” as compression is applied.
All that remains is to insert a limiter and listen to the mix before and after; naturally, the changes should be for the better. The main thing is not to overdo it. I repeat: moderation is needed everywhere; extreme device settings during mastering are completely unacceptable.
L2 limiter
In the Waves L2 limiter, set Out Ceiling at -0.2: this is the standard recommended to guarantee the absence of clipping after rendering (the thing is, apparently, a small amount of dither noise is mixed in, which compensates for quantization noise when reducing the bit depth; it is wild mathematics). Then do not forget to set the IDR module parameters: quantize—16 bit, dither—type1, noise shaping—ultra. All that remains is to set the threshold so that the mix’s RMS does not fall below -10 dB (which is normal for a mix). Now compare once again what you had with what you got; the result should amaze you =)
P.S. This applies only to preparing a mix specifically for publication; this article has nothing to do with mastering individual tracks.
Originally published by Etiket Weblog (etiket-music.com).
