I appreciate the fact that Stereophile actually measures the equipment that is under review, and the comparison between the measurement and the subjective review is fascinating (e.g., that $44K CD player). However, as a non-engineer and a relative newcomer to this mag, I'm wondering if there is some kind of website guide to what the measurements actually mean, and what difference they may have on the way a piece of equipment sounds. When it comes to THD and frequency response, those measurements are certainly straightforward enough. However, some things remain incomprehensible to me and I'm hoping someone can clarify some of these things.

For example, in the 9/06 review of the Paladin amp, Atkinson wrote: "...at '100k' the input impedance actually dropped to 6.9 ohms. This is low enough to give rise to a somewhat lean-sounding bass with some tube preamps that have a rise in their single-ended output impedance at low frequencies." OK, what does this mean? What is "single-ended output impedance"? In a more general sense, what is the relationship between impedance of an amp and frequency response?

What is "phase angle"?

In the Paladin review, Atkinson points out that the amp "doesn't perform well on the demanding two-tonw high-frequency intermodulation test," but adds, "it is veritually impossible for the amplifier to be asked to produce this kind of signal when playing music." I'm not criticizing, but merely trying to understand what pragmatic value this measurement has in understanding the way the unit sounds in operation.

In speaker reviews, why are some drivers measured nearfield (e.g., the midrange unit on the JBL 880 in the 9/06 issue), while others are measured farfield (the other drivers in the same JBL speaker)?

Thanks in advance for clarifying...