Down With Flat! Page 2

The paragon for lower-middle-range reproduction is the large horn-loaded system of the type used in recording studios and movie theaters, which more often than not sounds exaggerated through this range. But audiophile systems sound deficient here, even though designers' measurements show otherwise. And this region has a most profound effect on the ability of loudspeakers to reproduce the real timbres of real musical instruments. I have complained bitterly about this in countless speaker reports, yet my own response measurements have consistently failed to turn up any pattern of objective suckout through the lower middle range. And equalization to correct the sound has, with equal consistency, introduced a measured rise through the 300Hz to 1kHz range.

Perfectionist loudspeaker design has made tremendous strides in the past ten years toward improved detailing and imaging, and extension of the highest and lowest octaves of frequency range, yet that all-important issue of tonal accuracy has been consistently overlooked. If anything, the middle range, the whole foundation of sonic accuracy, is less felicitously reproduced today than it was 30 years ago. Those old horn-loaded squawkers had an awfully strident and dirty high end, but they reproduced the range from 100Hz to 2kHz with a degree of subjective accuracy not even approached by many of today's most highly esteemed audiophile speakers. It should not have been necessary to exchange an abominable high end for an equally abominable middle range, but that's what we've done. I don't give a damn what the measurements say—most modern speakers just do not reproduce that part of the range properly. If you doubt this, just pay close attention to the sound of the next live, in-the-flesh (brass) trombone you hear.

At the low end, things seem to be reversed from the high end. (That makes an insane kind of sense, somehow!) Invariably, loudspeakers that measure flat in my own listening room sound thin at the low end, while those sounding flat at the bottom measure as having a low-end rise. (The same correlation exists in another room of different size and shape in my house, so it isn't just the main listening room.)

So, what about the sanctity of flat response?

Sometimes the problem is not with the measurement, but the measuring technique. Many loudspeaker manufacturers measure frequency response in an anechoic chamber, which is senseless. Loudspeakers are never listened to in an anechoic chamber. Loudspeakers are listened to in real rooms, and in real rooms their measurements are quite different. Other manufacturers bury loudspeakers flush with the ground out doors, and measure response that way. Again, this bears little relationship to a real listening situation, as it does not show the influence of the listening room, and neatly suppresses all those little edge-diffraction effects which roughen the response of a free-standing speaker. But not even real-room response measurements assure that speaker systems sound the way they measure, because no two rooms influence speaker response in the same way (unless their dimensions, construction, and furnishings are identical).

What all this means is that there is no justification for viewing flat measured frequency response of loudspeakers as The Word of God. This sacrosanct measurement serves as little more than a crutch for designers who, for whatever reasons, are unwilling to apply critical, subjective judgments to the sound of their own designs.

I'm not advocating, of course, that we entirely abandon the criterion of loudspeaker response flatness. Peaks and dips are still peaks and dips, and they do adversely affect the sound. But when subjective accuracy and objective perfection are as clearly at odds with one another as they are in loud speaker design, we should reassess our approach to the latter in terms of the former, rather than merely shrugging off our contradictory subjective observations as "irrelevant."

I realize how much more difficult this is going to make the design process, as it is much harder to judge what's right than to measure it. But since we cannot, as of now, measure the ultimate rightness of a loudspeaker's response anyway, subjective evaluation is the only available alternative. Actually, this isn't asking all that much of loudspeaker designers—our equipment reviewers do it all the time. And they will be the ones critiquing that designer's products in Stereophile, and doing it subjectively. It's the only way that makes sense.—J. Gordon Holt

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