Jerry Portnoy is one of the world’s finest harmonica players. When he blows through the reed of his cigarette-pack-sized instrument, the sound is as deep and rich as Delta topsoil. He draws on the mellow tones of his mentor Big Walter Horton and the sax-like melodies of Little Walter, the power of James Cotton and the precision of Sonny Boy Williamson II. But he uses their legacy as a road map. As his new Down in the Mood Room (Tiny Town) attests, where he goes is always his own call. And that’s made Portnoy himself something of a legend to younger players and blues fans.

Although he lives in Waltham, he grew up in Chicago, where his father owned a rug shop on fabled Maxwell Street. Every weekend blues giants like Earl Hooker and Big Walter played the open-air market, sometimes even running an electrical cord for their amplifiers out of his father’s shop.

When Portnoy picked up the harp himself, he says, "That was it. I knew what I wanted to do." And within a few years, by 1974, he was sharing the world’s stages with Muddy Waters. Since then he’s co-founded the Legendary Blues Band, led a group with guitarist Ronnie Earl, recorded with Bo Diddley and a host of others, and been a member of Eric Clapton’s ’90s blues band, playing on the guitar hero’s live 24 Nights and the Grammy-winning From the Cradle.

Ask him what’s at the heart of great harmonica playing and he’ll answer without hesitation. "First of all, what moves people about music is sound. It’s not note selection, which is not to denigrate the importance of note selection in what you’re playing, but great music starts with a great sound. The primal kind of emotional impact of the sound of a note that gets into your chest — that moves you. And unfortunately people get distracted by all the wrong aspects of music. They rely on their eyes rather than their ears; they look at how fast somebody’s playing. None of that stuff counts. You can kill people with one note if you put it in the right place and that note has a human quality to it. That’s the strength of the harmonica. That reed on the harmonica is a really flexible thing."

Flexible enough that the instrument can, in the hands of a master like Portnoy, travel into any realm. With Down in the Mood Room, his third solo CD, he makes his first charge at the battlements of jazz. And he scales the walls. The album’s keystone is, of course, his graceful, big-toned playing. He swings through Horace Silver’s "Doodlin’ " like a one-man horn section — which was exactly his idea for its arrangement. He eases into the lush melodies of "Lullaby of Birdland" and "Stormy Weather," his shimmering vibrato and elegant bent notes singing with a diva’s élan. There are boogies and blues, too, including an especially nice jump blues, "You Rascal You," with the album’s producer and guitarist Duke Robillard laying down an ebullient vocal.

Portnoy explains his MO for Down in the Mood Room: "I’ve never just recycled Little Walter and Sonny Boy anyway. First of all, I am 58. I started hearing music at the end of the big-band era, small jump combos, all that sort of stuff. Plus I study a lot of the great songwriters, the Cole Porters, the Sammy Cahns. That stuff was imprinted on me early. So I am a lover of melody and the old standards.

"For this album, I thought about trying to apply the small harmonica to some of the material that it might be suitable for, because you have to kind of match the instrument to the music. The small harmonica, as opposed to the large chromatic harmonica, has got certain quirks and characteristics. I thought that if I could use the peculiarities of the small instrument, I could make a different kind of record.

"I wanted to use horns and have the harmonica work either with them or against horn pads and have the sound of the harmonica really stand up to the horns. There were some things I knew would work, like ‘Sentimental Journey.’ I listened to a lot of R&B sax: Gene Ammons, Red Prysock, Joe Houston, and others. And all the old stuff I thought could yield ideas, like Louis Armstrong and Count Basie. I felt if I could find riffs and melodies that played to the strength of the harmonica, it would be something special."

Portnoy will play an album-release gig at Scullers this Tuesday, March 19 (with Robillard on guitar), but Down in the Mood Room is already a hit with blues radio. When the disc reached stores, on February 26, it was riding at #1 on the Living Blues radio chart. That’s especially rewarding for Portnoy, since Tiny Town is his own label. The new CD is his second self-released product, following his very successful Blues Harmonica Masterclass instructional box. That set, available via his Web site, www.harpmaster.com, is the most detailed educational tool for harmonica available. It has sold 5000 copies.

"It’s an annuity," he says. "As a musician, you have to piece together a living. But, as I’m fond of saying, I became a musician because I was too lazy to work and too nervous to steal."

MORE HOT AIR. The harmonica is sometimes called the Mississippi saxophone, but Dennis Taylor has been playing the real thing since the ’70s. He came from his native Vermont to attend Berklee; in 1980 he moved to New Orleans, where he rapidly built a reputation as one of the country’s leading blues-sax sidemen. In 1985, after participating in the revival of soul singer Mighty Sam McClain’s career, he moved back to Boston and became an MVP of the New England blues scene.

Taylor has since played with a host of musicians, from Eric Clapton to Kenny Rogers to Shelby Lynne to Duke Robillard to Buckwheat Zydeco, with whom he toured for years and cut several albums for Island Records. And he continues musical relationships with guitarslingers Clarence "Gatemouth" Brown and Eddy Clearwater. In 1989 he moved to Nashville, and he’s there still, supplementing his touring and session gigs with lessons. That’s where his most recent accomplishment comes in: he’s penned what’s apparently the first blues-sax instruction book, Blues Saxophone: An In-Depth Look at the Styles of the Masters (Hal Leonard).

"I got the idea when I was on tour with Duke, hanging out in music stores while Duke was checking out guitars," he explains. "There were tons of books for guitar players but not many for horn players — especially in this idiom. That, coupled with the fact that guitar players I worked with would often say they copped their licks from horn players, inspired me to do the book. Other than Charlie Parker, my students knew hardly any of the greats. So I put together an in-depth history and analysis of the styles of the different players."

Those include everyone from Chicago blues stalwarts A.C. Reed and Eddie Shaw to classic honkers Big Jay McNeely and Red Prysock. The blues playing of jazz legends like Sonny Stitt, Lester Young, and Sonny Rollins is also covered. Each of the 18 sax pillars featured gets a bio, a photo, and charts of some of his characteristic playing. And the book includes a CD with corresponding examples that Taylor cut with a combo in the Three Little Pigs studio in Nashville with blues producer Fred James.

Scoring the publishing deal was easy. Taylor got a referral from a friend who writes for Hal Leonard and clinched it with one phone call. Then the book took six to eight months to write. "Hopefully this book will open students’ eyes to the fact that it’s not how many notes you play when it comes to blues. It’s not technical music. You need to organize your thoughts and be able to represent your solo in some form — with a complete beginning, middle, and end. It’s about playing with expression."

BLUE, NOT BLUES. By night, Victor McSurely plays Chapman stick for the Blue Man Group. But he also leads his own outfit called the Sweepers, and their new Hundred Hearts (Big Big) is a dream machine for art-rock fans. McSurely, who plays guitar on the disc, is joined by drummer Martin Bernert, vocalist Melisande, and bassist/guitarist Dave Traver — all formidable players with freewheeling imaginations.

It helps that he’s studied with King Crimson kingpin Robert Fripp, but the vivid soundscapes of tunes like "Chains" (whose lyrics give the disc its title), opener "The Big Fish," and the rhythmically intense "Flying" convey a sense of restless momentum, leaping from idea to idea, following threads of melody — whether in McSurely’s lead vocals, Melisande’s floating, melismatic colors, or the smart, energetic instrumental lines. Despite his inventive phrasing and big tone, McSurely has, he explains, been playing electric guitar for less than two years, having picked up the instrument after the group’s original guitarist left to play in Chicago’s Blue Man band. "The vision for the Sweepers was to have four musicians who would be capable of solo careers — the idea being that the group would be more than the sum of its parts in terms of quality. The message of the group is to really look at issues of individuality: trying to live with integrity, struggling to come up to that. Because the ills of a society are a reflection of how we relate to ourselves as individuals."

Certainly Hundred Hearts meets the Sweepers’ high standards with its fresh sonic approach and the quirky-but-hooky poetry of its lyrics. "The Big Fish," in particular, addresses McSurely’s social concerns, but with a sense of directness and naïveté that lets the song charm its way to its message.

McSurely is also the sparkplug for Daffi Nathanson & the Situation. Nathanson is a New York City–based writer whose work in the band echoes the Beat poets. He spins narrative yarns over the sonic bedrock of McSurely’s Chapman stick, Tom McCarthy’s guitar, Steve Wilkes’s percussion, and Jamie Edwards’s keyboards. Their flexible support and his delivery carry the torch ignited by the recordings of Lord Buckley and Jack Kerouac and held aloft today by John Sinclair and a few others.

To get either disc or find out more about the Sweepers or Nathanson, check out McSurely’s Web site, www.thesweepers.com, or catch them live at 10:30 p.m. on Tuesday March 26 at T.T. the Bear’s Place.