Years ago I did an all-day listening test of a half-dozen of some of the best small stereo speakers on the market, what audiophiles call mini-monitors. The idea was to see if these small speakers, little bigger than the proverbial breadbox, could really be the equals of much larger speakers. Indeed they are.

How could such room-filling sound come from such a small box? It was implausible on the (literal) face of it.Yet it was so.

The answer involves advances in speaker technology, especially in the manufacturing of woofers, which give us the bass; the construction of the speaker box itself, and computer software that can perfectly replicate a large anechoic chamber, which give speaker designers an important resource previously available only to universities and big corporations. The collective result is big-box sound from small boxes.

What has this to do with wine? Quite a lot, actually.The past 10 or 15 years has seen similar tweaking in wineries and vineyards around the world. Vineyard areas that once issued banal wines are now suddenly issuing wines that are compelling. (Think of just about any wine from Spain, for example.)

What’s changed? Partly it’s technology, as wineries everywhere now have computer-controlled presses, temperature-controlled stainless steel tanks, and — most importantly — winemakers with the experience and education to know how to use them deftly.

Vineyards, which seem immutable, have changed more than you might imagine. Vines are trained on new trellis designs that open the leaf canopy to greater sunlight and air circulation, which increase grape ripeness and reduce molds and fungus diseases.

More producers are turning to holistic cultivation practices such as organic or biodynamic grape-growing. This leads to healthier soils, which, in turn, help foster stronger, more disease-resistant vines with deeper root systems. And that, in its turn, creates more flavorful grapes.

The end result is a difference you can taste. You (or I) might not be able to trace precisely the cause of the improved goodness, any more than we can know precisely just how a cigar-box size speaker can sound so amazingly good. Yet our senses are sure: There is a difference.

The following wines are examples of just such evolutions of knowledge, technique, and sheer doggedness in tweaking things so that the result is both revelatory and indisputably wonderful.

HERE’S THE (SURPRISING) DEAL

TERROSO “DOURO” 2003, BAGO DE TOURIGA

Talk about big-box sound from a small box. How about the taste and dimension of a classic vintage port from Portugal’s Douro region delivered in the form of an easy-down-the-gullet dry red table wine?

Port, after all, is a strong, sweet red wine fortified by a dollop of grape brandy, which makes it potent and heady stuff that you merely sip. Transforming it into a truly drinkable dry red table wine seems a contradiction in terms, like, well, powerful bass from a small speaker.

But what’s often forgotten in port appreciation is the reason a great port is so distinctive: It’s the grapes. The Douro is home to indigenous varieties that deliver uniquely distinctive tastes and scents. Previously, only traditional port wine delivered these goods. But why not a dry red table wine?

Good question — and one that’s being asked today by several traditional port producers. After all, the market for port wine is limited, while that for a dry red table wine is vastly larger. The last decade has seen a string of ever-better dry red wines from the Douro made from the same grapes that make traditional port wine so tasty.

Terroso is one such wine. Composed of a blend of touriga franca (30%), tinta roriz (25%) and tinta barroca (25%) — with the balance comprised of other indigenous grapes — Terroso 2003 is a deep-hued, rich red wine with scents of dark chocolate, raspberry, wild herbs, and an intriguing gravel-road-after-a-light-rain dustiness. What’s more, the acidity is surprisingly crisp, creating a refreshing table wine. It is an ideal red, experience shows, for lamb.

Oh, and there’s one more implausible-but-true feature to Terroso 2003: its price. How does $8.50 a bottle at PJ Wine, among other adventurous retailers, sound?

WILLAKENZIE ESTATE PINOT BLANC 2005 / WILLAKENZIE ESTATE PINOT GRIS 2005

Which is the better of these two extraordinary dry whites from Oregon’s WillaKenzie Estate? I couldn’t decide, so I’ve included them both. Whichever one you land on you can’t go wrong.

Oregon’s Willamette Valley is famous for exceptionally good pinot noir. But it does not have much acclaim — nor does it deserve any — for equally compelling white wines. New and better clones were heralded as the answer for Oregon’s lackluster chardonnay performance. Yet the improvement is so far unpersuasive, at least to this taster.

Pinot gris performs better, but too many Oregon pinot gris wines are light, thin stuff. Dry riesling is Oregon’s consistently best white. But it’s a tough sell and in limited supply.

All of this is by way of background to the delight of tasting the 2005 pinot gris and pinot blanc from WillaKenzie Estate. Simply put, they are stellar. Not just for Oregon, mind you, but for their respective varieties. Few pinot gris or pinot blanc wines from anywhere in America — and much of Europe too, for that matter — are the equal of these two wines.

WillaKenzie’s 2005 pinot gris is dense, dry, and almost thick on the palate in the classic Alsatian style with striking notes of melons, pear, and tropical fruits. It’s one of the best pinot gris wines yet made in America.

WillaKenzie’s 2005 pinot blanc is that rarity of rarities: a pinot blanc with real character. (Most taste more like washed-out chardonnay.) Here you get a captivating scent of citrus, banana, honeysuckle, and talc with an invigorating edge of bitterness in the finish.

Both wines are sealed with highly desirable screw caps, which ensure a pristine freshness. Both are $18 a bottle. Supply is limited, but available and worth the effort to secure.