If these crisply produced, exactingly accurate, gorgeous, playful, emotionally rich singers don't win you over, then you're dead inside. Should that be your sad state of affairs, seek therapy.

Tony Lechner is not only the founder, director and sole faculty member of this (I can barely say it) high school ensemble (I'm sorry: high school? High school? How? Wha? … not … possible …), but he's also clearly a diamond miner. Lechner's done beautiful polishing and setting, but these singers are each priceless musical diamonds in their own right — amazingly, as both leads and ensemble singers. (Parenthetically (duh), I command that each of them continue to make a cappella music, lest they feel my wrath.)

Kudos also to Signature Sounds' Mark Thayer for a simple and elegant production. Whatever sound element you may focus on, there's just enough of it here. However, true devotees of the aca-band sound may find 5-Alone's low end a tad too low in the mix. But the choice is an artistic one: jazz over rock. (Fret not: rock still beats scissors.) The jazz bass is, after all, the gentler, nimble cousin to the thick-headed, pro-wrestler-esque rock bass.

Every high school small ensemble should have a copy of 5-Alone's Good Vibrations. It's a high-energy, high-accuracy, high-art bellwether.

I've noticed myself beginning to enjoy listening to high school a cappella recordings. There is some excellent work being produced out there. 5-Alone is definitely a part of the creme de la creme. They far outshine the usual high school a cappella.

Believe it or not, the major attribute of this group is the fact that all of them can sing. Surprising, no? Teacher and director Tony Lechner has put together an incredible ensemble of musicians — controlled, supported and naturally nuanced singers who handle tricky five-part harmony with an ease unmatched by most of their peers. I had to continually remind myself that these people were under 18 years old.

More often than not, they score as leads as well. O.J. Martori and Emily Kaufman are the standouts here. O.J.'s My Cherie Amour falls just short of being definitive, and Emily has a lilting soprano that completely captivates on her solos during Waltz for Debby.

But Erin Richardson. Holy cow. Mary, and I'll say it again Mary. She's gunning for Kelly Clarkson. I didn't give this a 5 because, frankly, I miss the upper "oh, oh, oh, oh, Mary" lines from the original in their rendition of the song.

Even though they are primarily a jazz group, 5-Alone does tend to wander into the pop and gospel genres. And as Mary and a solid Get Away Jordan can attest, the gospel they do with aplomb. Not so much with the pop, as it comes across, well, too poppy. And the subdued nature of their attack on the more upbeat tracks tend to bring down the overall energy of the album.

Good Vibrations is a great album — almost like a mini-The Real Group (A Cappella in Acapulco and Waltz for Debby are not to be believed). It's no wonder that this group walked away with the CARA award this year for best high school album and competed in the Boston regional of the Harmony Sweepstakes. They've got guts and talent — two things that will guarantee their longevity in the a cappella community.

Good Vibrations is an amazing album for a college group. The well-developed, rich, mature voices harmonize perfectly with a sweet, swelling resonance that is rarely heard even from professional groups. Soloists range from good to great as this vocal jazz ensemble tests its vocal chops on pieces as diverse as the Beach Boys and Take 6. I'm thrilled to hear young singers with a true appreciation for this tricky art.

I'm even more impressed that 5-Alone isn't a college group at all. This septet out of Hadley, Massachusetts is made up of students out of the Pioneer Valley Performing Arts Charter High School.

To be fair, Good Vibrations is not a perfect, flawless album, but it's damn good, even against professional standards. From Emily Kaufman's creamy, warm timbre on Waltz for Debby to knockout Erin Richardson's sultry, blues-inspired lead on Mary, these fine young talents vividly and exquisitely tackle some of a cappella's most tricky work. It's no wonder their accolades from the jazz community are starting to pile up sky-high.

I wasn't crazy about Sittin' on the Dock of the Bay, Get Away Jordan, or I Want You Back, pieces now well-established as a cappella mainstays. There wasn't anything terribly wrong with any of them, save the low-energy performance behind Arla Berman's intelligently executed solo. My first exposure to Icarus left me wanting more, but upon repeat listenings, I discovered a wonderful texture created through dissonant chords and a unique arrangement. The male vocalists in 5-Alone have a slightly less cultivated talent than do the women, but this is only marginally distracting.

Although my a cappella tendencies favor larger groups where voice parts are doubled or tripled, I was thoroughly impressed by the five part close harmony jazz 5-Alone seeks to recreate. NYC Winter completes the album, a piece that more closely resembles the choral sounds heard more frequently from high school and college groups. I have no doubts that as individuals, the singers heard on Good Vibrations are destined for greatness in the performing arts, and that as a group, 5-Alone will continue to raise the bar as a new standard of excellence in high school jazz.