Recently I had an artist ask me why the mixes he does in his home studio sound so much softer than the commercially released music he buys. I thought that everyone already knew about the whole "loudness wars" craze that has been going on since the late 1990s, but apparently there are still many people that don't know about this, or know how to make their mixes that loud.
So, here is a quick primer on the loudness wars, and how to get in the competition (if you desire to).
First off, there are already some great web pages out there talking about the loudness wars and the loss of dynamic range in music, so I won't repeat all of that hear, but simply recommend that you read one or two of these first, or do a search on your own for "loudness wars" (use the quotes for better results) on Google.com.
It's actually such a hot topic, that is has its own wikipedia entry, with everything you wanted to know about it:
http://en.wikipedia.org/wiki/Loudness_war
Still don't get it? Here's a simple and short audio & video demonstration of how it works:
http://www.youtube.com/watch?v=3Gmex_4hreQ
Now, I personally am NOT a fan of trying to make the music I work on louder, or even as loud, as some of these commercial releases. However, not everyone in the public is aware of the whole loudness wars issue and how it is destroying the quality of the audio we listen to, not to mention how fatiguing it is on the ears to listen to music mastered this way. The simple fact is that louder always sounds better to our ears, at least initially. It's a simple psycho-acoustic principal, that, unfortunately, has lead us to the whole loudness wars things, and can also get you into a lot of trouble when you are recording, mixing, or mastering your own stuff and you don't know any better.
So, the sad fact of the matter is that you have to do something to at least get your mixes up to the same general loudness ballpark as some of these commercial releases, or else the public and even DJs at radio stations, will think that your music is not very professional.
Since pretty much every home studio person is working in the digital domain, there is a limit to how much you can turn up the volume, or gain, of a signal before the peaks hit digital zero and begin to clip. When all the bits are on, there is no higher value, so if you try to raise the volume any more, you will simply clip off the tops of the peaks that exceed digital zero, causing a flattened top, effectively making a sort of square wave, and causing some very nasty digital distortion if you clip enough consecutive samples for it to be noticeable. You can see some examples of this by looking at some of the images that talk about the loudness wars.
But, it's not the level of the peaks of the waveforms that we perceive as the loudness of the track, rather, it is the average RMS level of the audio. If you are doing any type of modern music with drums or other percussive sounds, you will have many peaks in your audio that are well above the average level of your music. So, if you just normalize your mix, or mix in such a way that those peaks are right up to digital zero, your mix will still sound very soft compared to commercial releases since your average RMS level is still relatively low.
In order to make your mixes sound louder, you need to somehow lower the levels of those peaks so that you can then raise up the overall level of your audio, which will bring up the RMS level and make your mix sound louder. The easiest, and most common way to do this, is with a peak limiter. Although compression can help a bit as well, compressors generally have an attack time associated with them, which determines how long it takes for them to react once a signal crosses above the threshold. The attack time on most compressors is not fast enough to catch the loud and quick peak transients, so many of those slip through unaffected.
Digitally based Peak limiters usually use a "look ahead" feature, which delays the audio a bit so that it can scan ahead for upcoming peaks to be able to catch them in time and effectively bring down the level of the peaks in as smooth of a way as possible so that the peaks can be rounded off nicely instead of just totally flattened. They try to preserve as much of the shape of the waveform as possible, while lowering the level of the peaks. Peak limiters certainly sound better than simple clipping of the peaks, but they are still distorting the shape of the original waveform, and if you try to do too extreme of peak limiting, your audio will definitely get very harsh and crunchy very quickly. It generates its own form of distortion, and can definitely become unpleasant if abused, so be careful with it!
The first well know peak limiter plug-in for computers was the Waves L1 Ultra Maximizer. They are now up to version 3 (the L3 Ultra or Multi Maximizers), and there are many other companies that make peak limiters as well.
Some amount of peak limiting is a necessary evil these days, but if you use it sparingly and in moderation, you can safely bring the loudness of your mixes up to near commercial standards without doing too much damage to your audio quality. Just don't try to do this while you are mixing! Save a full, non peak limited version of your mix at 24 bit resolution, and apply any peak limiting as the very last step of the mastering stage, right before dithering down to 16 bits for your CD master. Better yet, don't do any compression or limiting on your stereo mixes, and leave that to a trained mastering engineer, and have him do one "loud" version for commercial purposes, and one high quality softer version that you can preserve for the day when the world comes to its senses and demands music that doesn't hurt the ears!
One thing you can do, though, if you are mixing "in the box" with software, is to occasionally put a peak limiter across the master buss and crank it up a bit so that you can hear how your mix holds up through the peak limiting process, and also so you can more easily do direct comparisons between your mix and commercially released CDs while you are mixing to check your overall levels and balance. But, only do that for short periods of time and then turn it back off again and do most of your work without it. Even if you decide to do your own quick and dirty "mastering" with that peak limiter turned on for the final mix, be sure to always make a version without it!
© copyright 2007, DBAR Productions, LLC
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