Quantitative thinking
I wish to thank Jim Austin for his January 2024 article on cartridge loading. He noted that the physics of cartridge resonance is qualitatively correct but not quantitively correct. The same issue is seen with cables: Litz construction sold as a way to address the skin effect, in which higher-frequency current is induced to move toward the wire’s surface, reducing the effective cross section and increasing its resistance. People who have not been trained in physics read about skin effect and spend more money to avoid it, not realizing that the skin effect becomes relevant only at frequencies well beyond the audible range. At audible frequencies, with about 10' of 8-gauge speaker wire, the skin effect causes a resistance increase of a few hundredths of an ohm at 20kHz. Put this in series with a 4 ohm loudspeaker, and the resulting attenuation is less than a percent. Nobody will hear that.
Barney Vincelette (PhD in physics and applied math) Houston, Delaware
Mr. Vincelette,
As a fellow physics PhD and hi-fi nut, I learned quickly that my PhD was less help than I expected. Few important problems can be solved conceptually. To gain real insight, you’ve got to do the work—the calculation—which requires a serious investment of time and energy even for people with real quantitative chops.
This cuts both ways. On the one hand, manufacturers occasionally turn to some scientific concept—a plausible-seeming mechanism—to justify a performance claim. To really make their case, they’d need to do the math (but how many customers would be able to follow the math?). On the other hand, if you want to disprove a claim, you’ve … got to do the math.
For what it’s worth, Stereophile reviewers are expected to ignore all that. They’re charged with setting aside preconceptions based on obvious nonsense or even correct science and prioritize what they hear. “Tell us what it sounds like” is our motto. We run into trouble when we start asking “how?” or “why?” before we finish answering “what?”. That’s why reviewers aren’t shown measurements before they submit their reviews; we don’t want measurements to bias listening impressions. It’s their ears we pay them for, and their ability to communicate what they hear.
Marketing aside, it comes down to how well a product performs. It’s the engineering that matters, not the engineering-speak.—Jim Austin
Full immersion
I am listening on my main rig to Bartók’s Concerto for Orchestra, Karina Canellakis conducting the Netherlands Radio Philharmonic Orchestra, in 5-channel DSD128. I am wearing Apple’s new Vision Pro, which leaves my ears free. I have selected the
“Mt. Hood” environment, which immerses me visually at the near shore of a tranquil lake surrounded by evergreens, the peak looming large on the horizon. It is raining gently. The sonic imaging—what the in-room surround audio system is presenting—I perceive more fully than ever before. It is far different from what I experience by closing my eyes. The equipment vanishes in a different way. As Kalman Rubinson has written, “The presence of the loudspeakers was wiped from my consciousness.” Every nuance of music and sound is there, the very essence of what I’ve pursued as an audiophile for more than 50 years. The technology of virtual reality opens a way to enjoy (and evaluate) our precious playback systems more deeply.
Desmond Fretz Camarillo, California