There's a lot to catch up on in this thread, and I'll do my best to be brief and yet thorough ... well ... maybe not brief ...
Speed Errors.
There are various types which correlate to the magnitude and distribution of the error. Chris alluded to this in the stylus drag discussion. At the lowest level is IM distortion discussed in my post above, and loosely equivalent to digital jitter in the sense that we don't hear this as pitch change or wavering but rather as a combination of harshness, a paradoxically rolled off top end, and bleached out harmonics in the mid-bass. As we work our way to longer time domains, we begin to hear timing errors - like the band isn't completely on the beat. Increasing the time domain further, we begin to hear shifts in imaging and pitch until we reach a point where nausea sets in for some of us. It's important to make these distinctions when we talk about speed.
Selection of Music.
I agree in general that acoustic music is critical to understanding what's going on, but this focus on period instruments is more a point of familiarity and reference for our friends on this list than anything else. It provides one (and I emphasize one) means of triangulating on the truth.
For an alternate, equally valid reality, listen to Bill Monroe, Doc Watson, Mark Knopfler, Neil Young, acoustic Jorma Kaukonen, John Fahey, Cal Tjader, Charles Mingus, Kathleen Battle, Talking Heads, Scissor Sisters, etc. and they'll all tell you something equally important about what's going on with your rig.
One of my favorite torture tests is to play a capable soprano going full tilt. Dense music has its place as well, and in this category, you can learn as much from Heavy Metal (even though I don't like it) as you can from full scale romantic pieces.
Rock 'n roll and other electronic music presents a challenge to understanding what's going on, but well recorded rock can also tell you things that you can't hear with acoustic music. You have to be watchful however. Listen to Neil Young playing his beat up Fender Tweed Deluxe, and if you know the sound of those amps and their harmonic overtones, it's unmistakable when a system gets this right.
Period music (Academy of Ancient Music) will tell you about subtlety, nuance and such. Other genres will tell you something different. When we had our Saturday night after hours session at the Audiofest, Palasr brought an AC controller which we listened to (designed by the same fellow who's working with Win on the Saskia controller as well as with us). Well, we're still hunting down a 3-phase motor, and the 2-phase we were driving was relatively crude sounding compared with our legacy controller.
If you listened only to pop and rock, this crudeness would have been lost on you, as bass lines had nice punch to them. A shift to acoustic music told the rest of the story however. Drej and Palasr will agree, I'm sure. One of the main dangers of trying to reach a conclusion when listening to electric music is that the distortions in the recording process can be masked by electronic distortions in your system.
In my humble opinion, a system needs to do it all, and if you limit yourself while you're evaluating, you may well be limiting your ultimate outcome. So, if you listen only to period instruments, should you also invite Jazzdoc over with his Scissors Sisters records. The reverse would be true as well - don't listen only to electric.
Ultimately, you're making choices, but listening to all different sorts of music at a minimum will expose you to different worlds, and the fellow who tells me that Woody Guthrie doesn't have a story to tell me and that all of the valid music was composed by white guys who died a hundred years ago is equally self-limiting as is the reverse. Ultimately, even if you listen to music written by dead white guys, you can still learn a lot that's relevant to you by listening to modern music occasionally.
Cheers,
Thom @ Galibier
