So you'll have to forgive me when I tell you: whatever you thought (and what I once thought, too) about great stereo speakers is simply not true anymore. Size doesn't matter. Well, not that much anyway.

The best small speakers -- what audiophiles call "high-end minimonitors" -- defy belief. If you close your eyes and listen to the music, you won't believe what you see when you open your eyes. It doesn't seem possible that such a small speaker -- a foot-high box about nine inches deep and maybe eight inches wide -- could make such a big, beautifully defined, resonant sound. Yet it's so.

The last decade saw a revolution in speaker design. "What people once thought was essential in a speaker, especially to achieve good bass, is no longer true," says Paul Paddock, a speaker designer whose design credits include the highly regarded (but now-defunct) Linnaeum speakers. "They thought you had to have size. You don't."

Paddock is a pro. And he has a pro's clear-eyed view of speakers, devoid of the oohing-and-aahing of enthusiasts. "Let's take bass reproduction," he begins. "That's always the biggest challenge in designing small speakers. And it's what everyone is dubious about."

According to Paddock, substantial bass in a small speaker -- an enclosure little bigger than the proverbial breadbox -- is both possible and easily explained. "First, you need high-power amplification, by which I mean 100 watts per channel or higher. Twenty years ago that was rare and expensive. Today it's relatively cheap and easy to find.

"The reason you need that kind of power is simple physics: you need a lot of oomph for bass extension," he says. "A small speaker has a four-inch or five-inch woofer. To get good bass it's got to physically extend -- literally push itself out of the speaker box -- pretty far. That takes sheer amplification guts."

The second feature is the woofer (the bass speaker) itself. "Twenty years ago a four-inch woofer could travel 1.5 millimeters to two millimeters," says Paddock. "Today's woofers can travel six millimeters." This linear movement is called "x-max" among speaker designers.

Why is this important? "To go one octave lower at the same output requires four times the amount of cone travel," explains Paddock. "At the same time it's got to resist distortion, as well as dissipate heat in the process. Today's woofers can do all this."

To test this, I enlisted a friend in the high-end audio business, Kurt Doslu, who co-owns Echo Audio in Portland, Oregon (www.echohifi.com). Doslu is what the geeks call a "golden ears." He hears things most dogs don't. And because he specializes in used high-end gear, he listens to a far greater array of stereo equipment than conventional retailers, who know only the handful of lines they carry.

The challenge was simple: assemble a half-dozen or so of the highest-rated minimonitors on the market today and give 'em a listen. Are they really worth the price, typically $1,500 to $5,000? Moreover, can tin-ear sorts such as myself, along with a bunch of cronies I invited over for the all-day listen, really hear a difference?

The lineup was formidable. Of what are arguably the 10 most highly rated minimonitors on the market today, we had seven of them: Proac Response One SC ($2,100 a pair), Joseph Audio RM7si Signature ($1,800), Sonus Faber Concerto ($1,900), JMlab Micro Utopia ($5,000), Dynaudio Audience 42 ($700), Totem Model One ($1,650) and Totem Mani-2 ($4,000). The speakers were placed on stands filled with lead shot (Atlantis Reference 24-inch, $400), the better to hear them at "ear level."

The accompanying electronics (which certainly affect how a speaker sounds) were chosen for their "neutrality": a Plinius 8200 integrated amplifier ($3,000) and an Arcam FMJ CD 23 compact disc player ($2,200).

OK, so much for geek-speak. How were the speakers? Were there any outright winners and losers, especially at this vaunted level?

As everyone knows, tastes in speakers are highly subjective. Some are "warmer," with a coloration that makes music sound liquid and round. Others are almost clinically neutral, which can sometimes fatigue you after a while. Yet others are exaggerated with boomy bass or shrill, sibilant highs.

Everyone's overall impression was simple: Wow! It was mesmerizing how much sound -- not just quantity but quality -- emerged from these shoebox-sized wonders. No two were alike, either.

One of the big favorites (mine, too) was the Sonus Faber Concerto. A modest-looking speaker made in Italy, this minimonitor had the magic to make you forget it even existed. You got caught up in the music (we played the same six tracks for all the speakers, from vocal to instrumental to choral). What's more, the louder you played the Sonus Faber Concertos, the better they sounded: sweet, liquid and bass-rich with lovely "musicality."

Another fave was the more neutral-seeming Proac Response One SC. On the first go-round it garnered respectful appreciation. But it wasn't love at first listen. However, after we heard all the speakers, and then returned for a second listen, the virtues of the Proac came immediately into focus. They were simply so clean, pure and transparent. They seemed "weightless."

The same, by the way, applied to the Totem Model One. Their speed, transparency and bass response were outstanding.

A surprise winner was the Dynaudio Audience 42. This was by far the cheapest speaker among these thoroughbreds, but it was easily the smallest, too: roughly the dimensions of a standard sheet of paper in height and width and about 10 inches deep. They are really small.

Yet the sound from these Danish-made speakers (the company's literature declares "Danes Don't Lie") was astonishing. Sure, they lacked the bass of some of the other larger speakers, but for sheer delineation of sound -- what audiophiles call "soundstaging," in which you hear the placement of instruments -- the Dynaudio 42 was a marvel.

I asked Robert J. Reina, a reviewer for Stereophile magazine who specializes in small speakers, just how these speakers could be so convincing. He ticked off the reasons in quick succession:

"First, you've got new materials that have appeared in the last decade or so," he says. "Things like Teflon capacitors, magnesium woofers, titanium tweeters and aluminum/nickel/cobalt magnets.

"Then, there's been a big improvement in the cabinets. Designers have learned how to brace the cabinets and line them with damping material. If you knock on the cabinets, you'll get a 'thunk.' They'll sound dead. That's good. This gives greater clarity and deeper bass response, as well as naturalness throughout the frequency range.

"Not least," he adds, "is design talent. This is really important. Previously, the best designers specialized only in the most expensive equipment. But in the past decade, there's been a trickle-down. Top designers have turned their attention to smaller, less expensive speakers. And they've gotten very good at designing small speakers."

Speaker designer Paul Paddock agrees. "Even though I am one, I really have to say that the designer is critical. And there's something else that's happened recently that's truly revolutionary that adds to that: computer software.

"A designer can now buy computer software for about $1,000 that replicates perfectly the effects of a large anechoic chamber. You can test your designs in a way that was previously available only to researchers at very big companies or large universities. Today, talented amateur designers can really compete at the very highest levels and create amazing speakers, if they're good enough."

Today's best speakers are not the big honkers we all drooled over in our college days. Sure, they're still being made, and some of them are swell. (And if you have a really big room, you do need a good-sized speaker.) But the "genius speakers," the ones that can rock your world (and your rock music), are now the high-end minimonitors. Give them a listen and you'll agree for yourself.