I've been examining some songs with a stereo vectorscope recently and most of them end up with something similar to this shape on the display [shown in the picture to the right].
This shows Jason Mraz's 'Did You Get My Message?' but I've also found it with other well‑known tracks. My question is this: how is it achieved? Looking at my own stuff through the vectorscope, I get something close, but far more rounded and erratic. Is it something done at mixdown or during mastering? I wonder if it might be something to do with the amount of compression used in popular music and the need for the music to sound good no matter what system it's playing from, be it iPod headphones or a club sound system.
Via SOS web site
SOS contributor Mike Senior replies: That vectorscope trace is a pretty good example of what hard‑limited or clipped masters look like: high RMS levels in both channels and lots of maximum‑level samples. The likely reason why your own mixes don't look like that is that you're not applying the same kind of extreme loudness processing that is used on mainstream commercial releases these days. Nor should your mixes look like that while you're mixing them, to be honest, because loudness processing is usually best left until the mastering stage, when you can best judge the fine balance between the loudness increase and any undesirable side‑effects that arise from it.
What you've spotted doesn't really have anything to do with how well the mix will translate across different playback systems, though, except in the sense that a mix with a reduced dynamic range will remain more consistently audible in environments with high levels of background noise. The key to achieving a mix that 'travels well' is careful comparison against commercial productions, using a range of appropriate monitoring systems, and there's no mastering processing that can compensate for that.