The mystery of good acoustics

As any knowledgeable audiophile will tell you, the room should be regarded as an essential “component” in one’s audio system. Jim Smith’s useful book Get Better Sound is dedicated to this maxim, as are two long chapters (14 and 15) in Robert Harley’s otherwise consumerist manifesto The Complete Guide to High-End Audio (for a review of the latter book, see my post to this site titled “Audiophile virtues”). And there are internet sites to help you determine the best parameters. Here are two: the amroc room mode calculator (https://amcoustics.com/tools/amroc?l=26&w=20&h=13&ft=true&r60=0.6) and the Cardas Speaker Placement calculator (http://www.cardas.com/room_setup_calculators.php).

And yet, acoustics, not to mention psychoacoustics, remains mostly a mystery. In 1969, when the reconstruction needed to fix the jinxed acoustics of Lincoln Center was finally completed, the great music critic Harold Schonberg wrote in the Times: “Acousticians grimly shake their heads when they talk about it. The cause of their science had been set back a century. Science? After the opening of Philharmonic Hall, on Sept. 23, 1962…the feeling in lay circles was that the ‘science’ of acoustics had as much validity as a prediction by a Delphic oracle or an astrologer in a tabloid newspaper.” The top acousticians in the world had spent years analyzing the world’s best concert halls, and yet the fruits of their labors and expertise had fallen, well, flat in New York. Why?

Why are Amsterdam’s Concertgebouw (1888) and Vienna’s Musikverein (1870) so blessed? Every seat in both of those houses is a good seat acoustically: subtle details are always audible without loud climaxes being shrieky or overwhelming; voices and instruments sound natural; orchestral balance manages to be right even dramatically “off axis,” and so on. The “science” of acoustics was primitive at best in the nineteenth century, and yet, despite the inevitable progress any science makes over time, no one really understands the magic of either of those venues sufficiently to recreate it today.

Let me offer two anecdotes that bring this mystery home to me personally. A dozen years ago, I visited a former student, and a fellow audiophile, who had become wealthy in computer engineering. At that time, he was living in a house his company had rented for him in Sacramento: architecturally undistinguished, it had a large living room with somewhat peculiar geometry and high cathedral ceilings. His system sounded fantastic in that room; the best I’d ever heard by that point in my experience with high-end audio. Then, the following year, he moved into a loft apartment in San Francisco’s Noe Valley. It, too, was large, with high ceilings, but it was almost cube-like in shape; he brought that same superlative system along with him. But in the new space, the same system sounded only passable, not exciting. Why?

My own system was mostly assembled before I moved from a simple cookie-cutter house to my present abode. In the former house, I had no complaints—but I had no idea what I was missing. In my present living room, the same components compare very favorably with systems costing more than ten times as much owned by fellow members of our local audio club. It’s simply a different, and vastly better, “system” than it was before, although it contains the same components. Again: why?

Remember the lesson of Lincoln Center before you rush to a confident answer. Jim Smith, with all his experience setting up systems for well-heeled audiophiles, doesn’t know the answer if the best in the business hired by New York’s cultural powers-that-were did not. So I don’t know the answer, and neither do you; room calculators, diffusers, and bass traps will only get you so far. Maybe this is a good thing; it keeps us experimenting, gives us perpetual hope for improvement. Maybe it also explains, in part, why so few audiophiles spend nearly as much time discussing room acoustics as they do obsessing over tubes vs. solid state, or power cords, or whatever else money can buy that might, just might, improve their sound without actually changing where they live.

But I have a theory.

First, prefer odd room geometry if you can. This claim is anecdotal, not dogmatic; if you have a different opinion, let’s hear it. But it’s my impression that odd geometry corresponds more reliably with good sound. Perhaps this is because the effects of one part of an irregularly shaped room will not be exaggerated, or cancelled, by the same effects produced by a mirror image on the other side. Anthony Grimani, of Grimani Systems, suggests that odd dimensions help to reduce standing waves. Placing your speakers at different distances from the side walls may also help, for the same reasons: whatever resonances are set up on one side will not be exacerbated by the other stereo channel, if the two speakers are different distances from their respective side walls. I’m guessing (this is ALL guessing!) that odd dimensions above will also be beneficial. A trapezoidal ceiling will be better than a flat ceiling, for instance. The lesson, if any of this is right, would be that the by far most common arrangement—a rectangular room, with the speakers placed as far out into the room as is practical from one of the short walls, and the listening position also placed as far into the room as possible—is likely to be better than putting your speakers right up against the far wall, your listening chair right up against the opposite wall (leaving the majority of empty space in the room free of audio objects, and therefore more useful for regular domestic purposes)…but it will not be optimal. A simple rectangle is not a good shape for a listening room, if you have an alternative. Again: this is a pure hypothesis, ungrounded in any kind of “science,” but consistent with my admittedly limited experience (see the two personal anecdotes above).

Second, materials. Different materials—dry wall, bricks, bookshelves full of books, furniture made of wood, upholstered furniture, hardwood floors vs. carpet, “acoustic” ceilings (popcorn or tiles) vs. dry wall vs. wood beams…—will absorb and reflect different frequencies, and various resonances and diffractions, in different ways. What’s best? I don’t know. But I don’t recall these parameters being discussed in any of the references I’ve mentioned above, which are specifically addressed to the importance of room acoustics. I’d guess, using the same logic as arrived at irregular geometry, that a mix of different materials is likely to be best.

One thing’s pretty much for sure. A recent post to this site praised the delights of listening outdoors. I was appalled by that post for social reasons. I live on 5 acres, and my nearest neighbor is about a quarter mile away, but still I would never consider subjecting them to my music by playing it outside! Anyway, audio equipment is designed to be listened to in enclosed spaces, not in the out-of-doors. With no reflected sound at all, I can’t believe an audio system can recreate the experience of being in a concert hall, or a jazz club, or any other likely music venue (even Woodstock, or the Hollywood Bowl, have reflecting structures that shape the sound). I’m unwilling even to try this in any case, out of respect for my neighbors.

So: Have you any secrets for maximizing room acoustics? Shape, furnishings, acoustic treatments? Magical devices (e.g., Schumann resonance generators)? Psychopharmaceuticals?