A Cappella

Nothing man-made can equal the human voice for soul-piercing emotional power. Prepare to discover the dizzying range of possibilities within the whoops, hollers, wails, and whispers that leap from the lips and tongue — no other instruments allowed. Bobby McFerrin stirs up a surefire cure for the blahs on "Don't Worry, Be Happy," as multiple McFerrins bubble up in a vocal-only pop-reggae bounce guaranteed to drown that frown. Billy Joel knows how to make the most of his vocals too — that finger-poppin', street-corner choir crooning "The Longest Time" is simply the Piano Man sans ivories, making himself into a one-man doo-wop crew. But you need only one voice to make your point when you can belt like Janis Joplin with the Sunday-morning soul of her shopping-list for the Lord, "Mercedes Benz."

In Next Steps, get up close and personal with the cries of fiery folkies and L.A. pop princes.

Sometimes a lone voice can ring out louder when there's nothing cluttering the air around it. You can feel the danger and drama of the domestic-violence snapshot "Behind the Wall" all the more when Tracy Chapman's mournful moan sounds as close as she is to the next-door nightmare she describes. And you can hear the a cappella family tree spreading its roots from close-harmony heroes the Four Freshmen's bittersweet ballad "Their Hearts Were Full of Spring" to the California dreamin' of Beach Boy Brian Wilson, whose epic pop suite Smile opens with the wordless wonder of Wilson's Freshmen-indebted vocal fantasia "Our Prayer."

An intimate audience with soul slingers and bluegrass belters awaits you in Deep Cuts.

When singers put it on the line and go a cappella, they're plugging straight into the very soul of a song. The stakes are high on R&B bard Arthur Alexander's love-and-death drama "Lonely Just Like Me," but the vocal-only demo version drags you so deep inside the heartache you can practically taste the tragedy. When bluegrass bigwig Ricky Skaggs quits pickin' long enough to lay his lungs into the spiritual "Talk About Sufferin'," the weight of worldly woes vies with the struggle for salvation right in front of your ears. And if you think you know Dobie Gray's "Drift Away," just wait until you hear the Southern soul man transporting you to a sweeter sphere with nothing but his God-given pipes, in a unique a cappella take on a tune that's been covered by everyone from Bo Bice to Bob Seger.

When everything is stripped away but the voice, music gets pared down to its essential truths. Hearing an a cappella performance is like having a magic key that lets you look inside the head — and more importantly, the heart — of the singer, so you can truly understand the emotions behind every note. Hear how much a voice can achieve, whether it's the Swingle Singers jazzing up the classical cookbook, Boyz II Men harmonizing up a gospel-soul storm on Beatles ballad "Yesterday," or bluegrass godhead Ralph Stanley targeting eternity itself with only his well-weathered voice for ammunition on "O Death." Wherever there's a great singer giving it his or her all with no instrumental assistance, we've soared in and snagged the song for this ultimate a cappella experience; so if the voice is your choice, get ready to rejoice.