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 August 15, 2005 A Little Learning A few days ago I stumbled across an issue of the now-defunct Audio magazine, in which then-editor Michael Riggs paid tribute to the Boston Audio Society, which was founded in 1972. The Society had been one of the most influential amateur bodies in hi-fi since its inception, largely because Boston was one of the major centers of audio manufacturing, and many of its leading lights participated in the group’s events. A significant number of prominent American audio journalists, including Riggs, earned their stripes contributing to the Society’s newsletter, The BAS Speaker, which at its peak had a readership of something like a thousand. Riggs originally sought out the organization because he found himself a student in Boston with an interest in music and audio equipment and not much knowledge of the latter. He joined to learn, and built a career on that.At about the time the BAS was being founded, I found myself in front of a typewriter writing audio reviews for the first time. I had already been an audio buff for many years, thought I was pretty knowledgeable about matters of sound, and, for a nonengineer, had a reasonable handle on the nuts and bolts. What I had to learn the hard way was how to listen critically. As a fan, I had spent lots of time listening at hi-fi shows and shops, and in a broad sort of way I could usually tell which components sounded good and which ones were awful. But that didn’t prepare me for the task of evaluating speakers for, say, a magazine. Remember, magazines almost never select for review products they expect to perform badly, and the better components are, the more they tend to sound alike. In listening tests conducted for several magazines over the years by the National Research Council in Ottawa, we were ushered into a dimly lit room with a visually opaque but acoustically transparent screen at one end, behind which were up to four loudspeakers. Above the screen was a display that indicated by number which speaker was playing at any given moment, as a technician switched randomly among them. A selection of musical tracks, chosen because we had learned that each was revealing of some aspect of speaker performance, was played as the speakers were switched. Sometimes a speaker would be so different from the others that it was immediately obvious; we still didn’t know what it was, but we could describe how it sounded readily enough. More often, however -- and increasingly over the years, as the general level of speaker quality improved -- our initial reaction would be to hear no difference at all. The resulting sinking feeling tended to abate fairly quickly as our ears became accustomed to the speakers and tiny differences began to reveal themselves. But the ability of all the listeners to identify those small irregularities had to be learned by experience accumulated over a number of years. For good or ill, once you’ve learned to recognize some of the anomalies, you can never again ignore them. For me, a breakthrough in figuring out just what I was hearing came when I first played with a graphic equalizer. This is an elaborate tone control that gives individual control over the frequency response in a number of narrow bands. It’s meant to correct response errors, but it can just as easily cause them -- and, in the hands of overenthusiastic audiophiles, it often does. By playing with the controls, especially in the middle frequencies, I began to become aware of the distinctive character of certain response shapes: a midrange depression gave a hollow, distant quality; a midrange hump resulted in a forward, hard sound; and so forth. Once I’d identified these sounds, I could always recognize them. All of the listeners for the various magazines in those days acquired similar skills, and we tended to play a game, albeit with serious purpose: In addition to describing in words what we heard, each of us would attempt to draw a rough version of the frequency-response curve we would expect to see for each speaker. When all the listening was over, we could compare these sketches with the actual measurements. It was astonishing how accurate they almost always were. I went through a similar sensitizing process when it came to flutter -- the rapid variations in speed in such components as turntables and tape decks. I had read about flutter, and had actually been listening to massive amounts of it all along, but I didn’t know what to listen for, and so wasn’t really aware of it or much bothered by it. Then I reviewed a tape recorder whose measurements revealed it to have an unusually high amount of flutter. I noticed that long, sustained notes -- especially piano -- had a warbly, honky-tonk quality that they didn’t have when the same recording was played on another machine. That was a gross amount of flutter, as it turned out, but once I knew what it sounded like, from that moment on I could spot it a mile away. At one time I believed that, even for someone sensitized to flutter, there was a threshold below which it was inaudible. That’s undoubtedly true, but I now think that threshold is much lower than I did then. The very first all-digital recording I ever heard had a beautiful, silky quality I couldn’t quite identify, but that my various colleagues could definitely hear as well. We finally concluded that what we were reacting to was a total absence of flutter -- a completely digital recording has none, more or less by definition. It also seemed to us that we were still hearing some flutter, even from very good analog equipment, although we might not be aware of it. Once we knew that, the threshold dropped. Today, I routinely hear flutter on CDs mastered from analog originals, and it seems much more obtrusive than it did with vinyl recordings, which had so many other things wrong with them as well. Sometimes acquiring such listening skills can be a pain. ...Ian G. Masters
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