Theory of Speaker-lution

The video-tech evolution has been swift and in-your-face. From the square little black-and-white picture tube, we went to "in living color," rear projection, and the flat-ering DLP, plasma, LCD, and OLED. And on these displays we've watched broadcast, cable, VHS, Laserdisc, DVD, Blu-ray, and HD DVD (and the occasional porno - okay, that's neither here nor there). Audio too has had its share of corner-turning: We went from Victrola to mono to stereo to 7.1 surround sound.

But what of that more modest sonic tool, our boxy little friend, the loudspeaker? Dare we call it "developmentally challenged?" Let's be honest (and don't worry, we can speak frankly - it's just us here): Haven't most speakers pretty much looked alike in the past, say, 50 or so years (the age, coincidentally, of Sound & Vision)? And have there really been any revolutionary audio upgrades in recent decades? You might even wonder why speaker-makers keep making new models!

The reality, though, is that the loudspeaker has indeed come the distance. True, its evolution hasn't been flashy: The pace of progress has been slow, and only in rare cases are new concepts broadly adopted. But evolved it has. And we can prove it.

We call to your attention a brief history of the speaker below and a supporting photo gallery above (click on the image to see the slideshow). Check them out, and you can just feel the progress.

Yes, this is our ode - our homage - to you, you loud, underappreciated little box o' sound.

The first speaker revolution 1958 is actually a great place to start, as that year marked the peak of what I call the first major revolution in speaker design. The launch of stereo LP records was causing a big stir, but many people who wanted to get involved found that trying to get two of the giant furniture-like speakers popular at that time simply wasn't going to happen. Yes, even back then, wife-acceptability-factor (W.A.F.) was a concern.

Saving the day was a newfangled speaker design called acoustic suspension, developed by Edgar Villchur and Henry Kloss at a small Massachusetts company they founded called Acoustic Research (AR). Now instead of needing speakers that looked like huge pieces of furniture, you could get deep accurate bass from what soon became known as a bookshelf speaker.

First introduced in 1955 as the AR-1, by 1958 it had developed into the AR-3, which also pioneered the first dome midrange and tweeter drivers. Now anyone who could swing the AR-3's considerable cost could put together a stereo music system that wouldn't overtake the living room visually.

During the following 30 years we saw continual refinement of Villchur's basic acoustic suspension design, embracing a host of improvements in both driver and cabinet materials. After a few years, designers discovered you could generate even deeper and more powerful bass if you vented the enclosure through a critically tuned opening - the so-called bass reflex design. At first, determining the size and position of the opening, or port, was pretty much a black art. Then a series of scientific papers published in the early '70s by A. N. Thiele and Richard Small removed most of the guesswork.

Even though audiophiles continued to embrace a wide array of more exotic speaker types, it was those based on these basic acoustic suspension and bass reflex designs that continued to dominate most speaker development until the early '90s.

The second speaker revolution Just as the need for two speakers to play stereo had created a market for bookshelf speakers in the late '50s, 35 years on, people started embracing four- and five-channel surround sound rigs for movie watching, making those bookshelf speakers seem awfully big and clunky once you tried to squeeze in five of 'em. Certainly, the speakers could be made even smaller. Unfortunately, as the size diminished, so did the bass performance.

The time was right for the second major revolution in speaker design.

By recognizing that low frequency sounds are essentially non-directional, researchers at both Bose and Atlantic Technology figured you could take the deep bass information from each channel and combine them into one signal that feeds a dedicated bass-only speaker called a subwoofer. Launched almost simultaneously in 1989, the Bose Acoustimass 5 and the Atlantic Technology Pattern 100 defined a new speaker topology that is now almost universal in value-oriented systems.

And thus, the main speakers, now freed from the need to play low frequency sounds, could be made much smaller - yet they'd still deliver the essential spatial and directional information. These so-called satellite/subwoofer systems were soon available in expended versions, handling the additional channels required for surround sound. Today we refer to these as 2.1 or 5.1 channel systems, where the first number denotes the number of main speaker channels, while the .1 denotes the subwoofer.

Subwoofers were nothing new in 1989, but earlier subs were merely made to extend the low frequency reach of what was essentially already a full range speaker. The small satellite speakers in the 2.1 packages, on the other hand, were designed for use only in concert with their dedicated subs.

Now go to our photo gallery to see some of the little (and big) boxes that have made audio history.

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