Mastering: Limiting vs. Clipping
Posted: Wed Aug 01, 2007 12:08 am
Here's a confession: I like loud. But, as everyone knows by now, <a href="http://www.youtube.com/watch?v=3Gmex_4hreQ">loud can sound pretty damn terrible</a>. When mastering my own songs the penultimate stage (dithering comes last) is always volume maximization, which I achieve through a combination of Brickwall Limiting and Clipping. Just a quick refresher: Brickwall Limiting is like a compressor with an infinite ratio, and when mastering rock songs it increases the song's volume by softening the loudest elements of the mix (typically the kick and snare hits); Clipping is like your headphones breaking, and it increases the song's volume by distorting the loudest parts of the mix (again, typically the kick and snare hits). In breakfast terms, aggressive limiting makes the song sound "mushy", while aggressive clipping makes the song sound "crunchy". Notice that both processes make the song sound <em>worse</em>, NOT better, so I try to minimize the damage I do when applying either.
Recently I've been noticing that limiting is sounding worse and worse to me, while clipping is sounding more transparent. I've been finding that a well-mixed song can handle being clipped a lot more gracefully than it can handle being limited. So, I did this little experiment with one of my Nur Ein songs, <a href="http://www.forkbomb.ca/songs/demos/puce_bp.mp3">Brownie Points</a>. In the picture below, the red waveform in the background is the un-maximized version of the song: notice that it has a nice, natural looking ebb-and-flow to it, with reasonable dynamics and obvious drum peaks. I took this mix and applied about 4db of peak reduction, producing two "maximized" versions using limiting for the first one and clipping for the second (in the image the "maximized" track has been volume-matched and superimposed in green over the original). Notice that all the drum peaks have been truncated: from 1:38 onward the song looks literally square-wave.
<center><a href='http://www.forkbomb.ca/wordpress/wp-con ... veform.gif' title='Brownie Points Clipped (but not from the Betty Crocker catalogue)'><img src='http://www.forkbomb.ca/wordpress/wp-con ... veform.gif' width="483" alt='Brownie Points Clipped (but not from the Betty Crocker catalogue)'></a></center>
Here are the resulting tracks (at a high bitrate). If you want to compare them you'd probably be best off skipping to the end of the song where things start to go a little crazy.
<blockquote><li><a href='http://www.forkbomb.ca/wordpress/wp-con ... cessed.mp3' title='Brownie Points Unmastered'>Original, Untreated Mix</a></li><li><a href='http://www.forkbomb.ca/wordpress/wp-con ... atched.mp3' title='Brownie Points Clipped'>With ~4db of Clipping</a></li><li><a href='http://www.forkbomb.ca/wordpress/wp-con ... atched.mp3' title='Brownie Points Limited'>With ~4db of Limiting</a></li></blockquote>
I then did several <a href="http://en.wikipedia.org/wiki/ABX_test">blind ABX tests</a>, and was surprised to find that I could hardly tell the difference between the clipped version and the original. The main difference I noticed was that the kick drum sounded a little more constrained in the clipped version. However, I had no problem distinguishing the limited version, as the softening of the kick and snare during the song's loud sections makes it sound noticeably wimpier than the original. Although I won't post them here, I also did a few mixdowns with a blend of limiting <strong>and</strong> clipping, but found that nothing sounded as transparent as just straight clipping. Here is the mastered track without the volume matching (WARNING - this is a lot louder than the other tracks): <a href='http://www.forkbomb.ca/wordpress/wp-con ... lipped.mp3' title='Brownie Points Mastered'>Brownie Points Loudified</a>.
So, what have I learned from all this? From now on when I'm mastering my own material I'll avoid using a limiter if I don't have to.
Taken from my blog.
Recently I've been noticing that limiting is sounding worse and worse to me, while clipping is sounding more transparent. I've been finding that a well-mixed song can handle being clipped a lot more gracefully than it can handle being limited. So, I did this little experiment with one of my Nur Ein songs, <a href="http://www.forkbomb.ca/songs/demos/puce_bp.mp3">Brownie Points</a>. In the picture below, the red waveform in the background is the un-maximized version of the song: notice that it has a nice, natural looking ebb-and-flow to it, with reasonable dynamics and obvious drum peaks. I took this mix and applied about 4db of peak reduction, producing two "maximized" versions using limiting for the first one and clipping for the second (in the image the "maximized" track has been volume-matched and superimposed in green over the original). Notice that all the drum peaks have been truncated: from 1:38 onward the song looks literally square-wave.
<center><a href='http://www.forkbomb.ca/wordpress/wp-con ... veform.gif' title='Brownie Points Clipped (but not from the Betty Crocker catalogue)'><img src='http://www.forkbomb.ca/wordpress/wp-con ... veform.gif' width="483" alt='Brownie Points Clipped (but not from the Betty Crocker catalogue)'></a></center>
Here are the resulting tracks (at a high bitrate). If you want to compare them you'd probably be best off skipping to the end of the song where things start to go a little crazy.
<blockquote><li><a href='http://www.forkbomb.ca/wordpress/wp-con ... cessed.mp3' title='Brownie Points Unmastered'>Original, Untreated Mix</a></li><li><a href='http://www.forkbomb.ca/wordpress/wp-con ... atched.mp3' title='Brownie Points Clipped'>With ~4db of Clipping</a></li><li><a href='http://www.forkbomb.ca/wordpress/wp-con ... atched.mp3' title='Brownie Points Limited'>With ~4db of Limiting</a></li></blockquote>
I then did several <a href="http://en.wikipedia.org/wiki/ABX_test">blind ABX tests</a>, and was surprised to find that I could hardly tell the difference between the clipped version and the original. The main difference I noticed was that the kick drum sounded a little more constrained in the clipped version. However, I had no problem distinguishing the limited version, as the softening of the kick and snare during the song's loud sections makes it sound noticeably wimpier than the original. Although I won't post them here, I also did a few mixdowns with a blend of limiting <strong>and</strong> clipping, but found that nothing sounded as transparent as just straight clipping. Here is the mastered track without the volume matching (WARNING - this is a lot louder than the other tracks): <a href='http://www.forkbomb.ca/wordpress/wp-con ... lipped.mp3' title='Brownie Points Mastered'>Brownie Points Loudified</a>.
So, what have I learned from all this? From now on when I'm mastering my own material I'll avoid using a limiter if I don't have to.
Taken from my blog.