Nine Inch Nails - Closer . Trent produces his music to a high standard, so there is detail in there to be found on a good system. Two particular parts I listen out for. In the intro the bassline is a very deep and powerful crunching noise, but if you listen carefully there is a delicate melody playing behind it. On a poor quality system this is pretty much inaudible, but as your system quality improves, and in particular it's abbility to service the mid and high while still pumping out bass, this melody comes up in the mix to the point where it's almost more prominent than the bassline. Really good way to hear how agile the system is. Later on in the middle of the song there is an instrumental break with the same crunching bass overlaid with loud guitar sounds and synth. But again, if you listen carefully there is a quieter track going on in the background. In this case it's spoken vocals played at a lower level, almost like a whisper behind the music. As with the intro, on a poor quality system you won't hear this at all as the grinding bass absorbs all the power, but as your system gets better the vocals become clearer and clearer. You need a pretty good system to be able to make out what he's actually saying, but when a system can do it you hear it so clearly its hard to understand how you could have missed it before. I love using this track for testing as these two parts make it really easy to empirically assess the clarity of a system by whether you can hear the background tracks or not.
The other track I frequently use is Under the Bridge by the Red Hot Chilli Peppers. The opening sequence is quite quiet and with a good system you can hear his fingers moving on the strings and body of his guitar, good way to assess detail. Then later on you have the whole band playing loudly with a chior behind them, so there is lots going on at fairly high volume to test the range.
I've also occationally used some stuff by Rob Zombie on his solo album Hellbilly Deluxe. e.g. Superbeast or Dragula (original version on the album, not the compressed one on the Matrix soundtrack which sounds flat). Might seem an odd choice, but like Trent he produces his music to a migh standard, so as the system improves you can hear more and more going on in the track. As with closer, there is huge powerful bass being fired out here, with lots of other stuff going on in the background. A system lacking in power will run out of oomph pushing out the bass and lose all the detail of the other sounds. First time I auditioned an active sub system I used this and it was like listening to a new song!
