Vbr Mp3 Encoding During (pre-)mastering

By Author: Lorenz Vauck
Total Articles: 3698
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Back in 2004, One to One magazine published an article about the mastering industry, and a portion of this included my comments on MP3 encoding. Since I am sometimes asked about how to get the best quality MP3s possible, and because such a thing is generally quite useful, following are my comments (partially based on the aforementioned interview).

One piece of software that I continue to commonly use when preparing tracks for Internet Distribution (at least in MP3 format) for my mastering clients is known as the Lame MP3 encoder. I can tell you that it certainly is anything but 'lame,' offering an absolutely massive variety of modifiable parameters. In a sense, it's a 'dream' piece of software for anyone who wants to tweak MP3s to perfection. There's also the ability to use some experimental psychoacoustic tunings too, which is of course an added benefit.

VBR (variable-bit-rate) encoding works particularly well too with The Lame -- it's not at all inferior to CBR (constant-bit-rate), and adds just that much more "edge" to complex portions of the music being encoded. ...
... Using my (admittedly quite refined) methods, I can achieve results at 192kb (average VBR) that has frequency response fluctations of less than +-0.2 dB in the entire 20-18,000 kHz range (and less than 1 dB in the range above this). Also, stereo imaging is perfect when compared with the uncompressed WAV master.

The caveat here though is that there's a very noticable drop in quality at bitrates lower than this. Of course, now that broadband is becoming more widespread every day, it's not really much of an issue to distribute MP3s at a higher bitrate than one would back in the analog modem days, as download time differences between 192kbps and for example 128kbps aren't really significant for most people anymore. Another caveat is that if one is not careful in the encoding process, it's easy to have lost peak limiting and clipping. This is why I often will reduce song volume by a dB to compensate.

So, the lesson is that it really is possible to have really good sounding MP3s, provided that one is careful and thoughtful when doing the job, and does not use too low of a bitrate.