darrenyeats wrote: > Arny, that's one thing Siegfried states. > Please remember that you brought this document into this discussion to apparently counter my comments about IM. That you seem to feel to do such a thing tells me that you don't understand what I'm trying to say.
> > Also, he rates the drivers by HD and picks them on a combination of IM > and HD performance. Implying HD is significant and not made moot by IM. > Again, it appears that you are not understanding the core of this discussion. > > I do see your point TBH, I just think you're over-egging the pudding. You appear to be grasping at any straw to avoid the point of my comments. Let me throw a few more eggs at the problem: ;-) (1) THD and IM are not forms of distortion. The forms of distortion are linear and nonlinear distortion. Not seeing IM or THD on that short list, they must be absent for a reason and the reason is that they are irrelevant to a discussion of forms of distortion. I say so, Geddes says so, Linkwitz says so, a ton of other recognized authorities you may not have heard of say so, by gosh it could even be true! ;-) (2) Well then, what are THD and IM if they are not forms of distortion? They are means for characterizing or quantifying or measuring distortion. They are means, not the ends. Are cubic centimeters a form of automobile engine displacement? No! Cubic centimeters are a means for characterizing or quantifying or measuring engine displacement. (3) THD and IM are means for measuring nonlinear distortion, so what is nonlinear distortion? Nonlinear distortion is a something whose fundamental cause is things that take in one tone and put out more than one tone, where the additional new tone(s) have a more-or-less consistent correlation with the input. This contrasts with noise and interfering signals where that correlation is random. This contrasts with frequency response and phase distortion where the same tones that go in, come out but with their relative timings and/or sizes changed. (4) Can you estimate IM given THD or vice-versa? Yes you can. The procedure is that you estimate the underlying form of nonlinear distortion from either THD or IM measurements or better yet from a FFT analysis, and then simulate the other measurement based on what you find out about the distortion mechanism at hand. This would be more popular except for the fact that are about an infinite combinations of number of tones, tone frequencies, and tone amplitudes for measuring THD and IM, and the relationship depends on which set(s) of tones you chose to compare. My point is that if you have IM, you have THD and vice versa. They are basically equally important because they are like two sides of the same coin, and the coin is named *nonlinear distortion*. Harmonic distortion can possibly be euphonic or at least hard to detect because it is often masked by the harmonics that are already naturally in the music. IM has this nasty strong tendency to sound ugly to most people, except possibly people who like things like Punk Rock or Heavy Metal. Thing is, Deep Purple sounds better to me on a measurably clean system than a dirty one. The fact that the mainstream of audio is highly dependent on the existence of gear with vanishing or at least inaudible distortion is a matter of historical fact. Of course like most avocations there are many tiny niches in audio that may defy conventional logic. ------------------------------------------------------------------------ arnyk's Profile: http://forums.slimdevices.com/member.php?userid=64365 View this thread: http://forums.slimdevices.com/showthread.php?t=106914 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
