The sound of the human voice is the result of breath flowing against an individual’s vocal cords, vocal folds closing and opening at regular intervals, essentially chopping the airstream into small pulses. Remarkable when one stops to think about how that pulsing air and vibration from an instrument so small is the means by which a great singing artist communicates with her audience.

The voice that emanated from mezzo-soprano Isabel Leonard on Sunday afternoon at Clayton State University’s Spivey Hall was opulent, truly the fusion of physiology and finesse.

Leonard is the final solo singer in what has been an incredible lineup at Spivey Hall this year, following memorable performances from baritone Simon Keenlyside and countertenor Andreas Scholl. Next season’s schedule is set to be announced today, and it will be difficult to outdo this year’s cast of singers.

A graduate of Juilliard who has already sung leading roles, including Miranda in Adés’ “Tempest” and Rosina in “Il Barbiere di Siviglia“ at the Metropolitan Opera and abroad, Leonard was raised in New York by an Argentinian mother and an American father. Her program made sense in that light, showcasing a potpourri of Spanish songs in the first half and songs by U.S. composers, including three world premieres, following intermission.

Statuesque and gorgeous, Leonard is exceedingly expressive. Every song was a vignette, riddled with subtleties of face and gesture, ideal for the intimacy of a vocal recital. Moreover, she constructed a smart program, highlighting her Spanish fluency and rich vocal timbre. Accompanied by Romanian pianist Vlad Iftinca, she opened with a rarely heard Andalusian song by Manuel de Falla, “El pan de Ronda,” and one of Victoria de los Angeles’ signature pieces,  “Clavelitos” by Joaquín Valverde Sanjuán. Her delivery was casual and utterly spontaneous. Leonard makes singing look easy.

The second song group consisted of disparate selections by late-19th-century and 20th-century Spanish composers. Beginning with “Gracia Mía,” excerpted from Enrique Granados’ “Canciones Amatorias,” the singer created a narrative about a mother who first professes that her child is the most beautiful creature she has ever seen. That was followed by Manuel de Falla’s “Oracion de las madres que tienen a sus hijos en brazos,” the prayer of a mother that Jesus would spare her infant son the life of a soldier. The third selection, “Sólo las Flores Sobre ti” by Federico Mompou, is a song about death and grieving. Leonard closed her song cycle with Falla’s angst-filled “Olas gigantes,” in which the mother begs the immeasurable waves to have mercy and swallow her up, eradicating her memory and reason. A young mother herself, Leonard infused this set with intensity. Iftinca was just as vibrant as the pianist, bringing forth lush harmonies.

Leonard highlighted the songs of three contemporary American composers as well: Jennifer Higdon, Glen Roven and Ben Moore. Of the three world premieres, Roven’s setting of Emily Dickinson’s poem “Wild Nights” is a keeper. It’s not as frenetic as Lee Hoiby’s setting, and the vocal range is more limited. But Roven has composed an apt setting for the poem and does it justice, with agitated and repetitive piano figures set against a sweeping vocal line.

At Spivey Hall this weekend, Isabel Leonard definitely proved that she’s more than just a pretty face. She is just as proficient singing Cole Porter’s “Where, Oh Where” as the “Cinco Canciones Negras” of Xavier Montsalvage. And her Rossini isn’t bad either.

If you’ve seen Steven Spielberg’s recent movie “Lincoln,” you’ve seen and heard soprano Mary Dunleavy. The singer, who makes a cameo appearance in the film while Abraham and Mary Lincoln discuss potential legislation in their box seats at the opera, graces Atlanta with her interpretation of Violetta Valéry, the female protagonist in Giuseppe Verdi’s opera “La Traviata,” which concludes Sunday at the Cobb Energy Performing Arts Centre.

The casting of Dunleavy as the 19th-century Parisian courtesan was brilliant. Violetta is apparently her signature role, one that she has reprised at the Metropolitan Opera several times. It was evident that she was entirely comfortable inhabiting the role here with the Atlanta Opera as well.

Verdi dominated and revolutionized Italian opera in the interim between Donizetti’s last bel canto hit, “Don Pasquale,” in 1843 and Puccini’s initial verismo success, “Manon Lescaut,” in 1893, but his “La Traviata” is still very much steeped in the tradition of elegant vocalism and double-aria forms that his predecessors Donizetti, Rossini and Bellini established during Verdi’s formative years. Armed with incredible dramatic instincts and musical genius, Verdi created in ”La Traviata” an enduring domestic tragedy centered on Violetta Valéry’s sacrifice for her beloved, composing what has become one of the most popular and performed operas in the repertoire.

Verdi undoubtedly would be pleased with the Atlanta Opera’s staging of the work, because Dunleavy delivers an exquisite performance of his heroine in every aspect. Her Act I singing of the cavatina “Ah forsé lui che l’anima” and the following cabaletta were captivating. She possesses a voice with squillo, a.k.a. ping, omnipresent in both sustained and agile passages. Her voice and look were transfigured in Act III for Violetta’s final act and aria, “Addio del passato.” The squillo was gone, but not the lovely core of the sound or the brilliant legato. (Happily, Dunleavy is scheduled to return to Atlanta next season in the role of Gounod’s Marguerite.)

Conductor Joseph Rescigno returned to lead the opera orchestra and a cast that was almost ideal. Baritone Weston Hurt, last heard in Jun Kaneko’s controversial “Madama Butterfly” in 2008, sang the role of Giorgio Germont with wonderful proficiency and warmth. He negotiated the upper reaches of “Di Provenza” with utter ease, and his singing complemented Dunleavy’s throughout their lengthy, four-movement duet at Violetta’s country home in Act II. Regrettably, however, Russian tenor Boris Rudak did not impress in the role of Alfredo. His lovely timbre and admirable legato were overshadowed by passages of questionable intonation and awkward moments onstage.

David Gately directs the Atlanta Opera’s “Traviata.” Several years ago, Gately constructed a clever “La Cenerentola” at the Cobb Energy Centre with Jennifer Larmore in the title role, and it’s evident that his work is most satisfying in scenes that involve comedy and a wealth of stage business. Flora Bervoix’s party, heavily populated by the stellar Atlanta Opera Chorus and set within a monochromatic scarlet drawing room, is just such a scene. A single Gypsy girl (dancer Tamara Merritt Irving) entertained the inebriated guests, including Gastone (played by tenor and natural comedian Wesley Morgan), and created both strife and passion between Flora and her love interest the Marquis D’Obigny, sung by the talented mezzo-soprano Maria McDaniel and bass-baritone Jason Hardy.

The Opéra de Montréal production, last seen at the Boisfeuillet Jones Atlanta Civic Center in 2005, was revived and reassembled this season, but much has happened to the Atlanta Opera while the handsome Claude Girard-Bernard Uzan sets were hibernating. Dennis Hanthorn arrived as general director, implemented strategies that put the company into the black and secured a more glamorous and suitable venue at the Cobb facility. Now, seven months after Hanthorn’s hasty resignation, the opera’s board of directors is almost at the conclusion of its search for a new visionary.

Matthew Guard founded the Skylark Vocal Ensemble, a chamber group of 17 choral singers from Boston and Atlanta, in 2011. Guard is a Harvard graduate who studied conducting during his undergraduate years but changed course soon afterward, earning an MBA and working as a business strategy consultant here and abroad. After five years, he rediscovered his initial vocation and the Skylark Vocal Ensemble took flight. And it’s a gem, a group of proficient soloists who have come together to create a dynamic and inspiring whole.

The Skylarks are performing three concerts in the Atlanta area this season, and the first was heard Sunday at Holy Spirit Catholic Church in Sandy Springs, a fitting milieu for a concert titled “Something About Mary.” It was an intimate, a cappella evening of ancient, Romantic and modern hymns to the Blessed Virgin.

The women in the group began the concert from the entrance of the sanctuary singing “Alma Redemptoris Mater,” a chant consisting of a single melodic line excerpted from the Canonical Hours, a Roman Catholic service dating from the Rule of Benedict circa 520. The Canonical Hours comprise prayers, psalms, canticles, responses and antiphons sung every day in a regular order. In fact, Guard programmed all four Marian antiphons, chants typically sung in monasteries during Compline at the close of the day, immediately after Vespers.

Skylark’s male chorus took up the energetic monody “Salve Regina,” and then the entire ensemble delighted us with Tomas Luis de Victoria’s Renaissance-era composition of the “Ave Regina caelorum” in five-part polyphony. The antiphons concluded with a dramatic rendition of the 1535 “Regina caeli laetare” by Nicolas Gombert: 12 individual melodic lines, minimalistic and lush. The acoustics of the sanctuary refined and amplified each looping melody, and the ensemble sang sans vibrato, with a remarkable unity of timbre.

From time to time, Skylark members stepped forward, breaking the wall between performer and audience, to introduce certain selections and advise us on what to listen for in them. We heard four of the seven parts of  Brahms’ Marienlieder Op. 22, strophic settings that were most likely influenced by Bach. The settings are syllabic, with rare moments of surprising melisma. One narrative, “Der Jäger,” recounted the Annunciation and introduced Gabriel as a hunter blowing his horn. The entire song was subdued and monodynamic until the end, when the singers forcefully proclaimed “Da empfing sie Jesum Christum” (“She then conceived Jesus Christ”) and followed it with a lovely pianissimo “in ihr jungfräulich Herz” (“in her virginal heart”).

Of particular interest was Skylark’s set of songs by 20th-century British masters Benjamin Britten and John Tavener. Britten’s “Hymn to the Virgin” features a double choir, the first of which sang of Mary and her task on earth in English. The second choir, merely a quartet, functioned as a sort of Greek chorus, commenting in Latin at regular intervals. Tavener’s “Hymn to the Mother of God” consisted of a double choir in canon. The ensemble gave us a wash of sound with long, sustained tones, vacillating in and out of dissonance.

The evening came to a close with several well-chosen and dissimilar settings of the “Ave Maria,” by Robert Parsons, Anton Bruckner and Sergey Khvoshchinsky, leaving us to contemplate the Blessed Mother’s grace and the beauty of the human voice.

Andreas Scholl is one of the world’s leading countertenors.

Countertenors are what one would call a rare breed among classical singers. Alfred Deller set the stage during the 1950s and ’60s in terms of popularizing the sound of a male alto who sings exclusively in his falsetto range. But it remains unusual to have the opportunity to attend an opera or recital in which an accomplished countertenor performs. It was thrilling, then, to hear German countertenor Andreas Scholl and his wife, pianist Tamar Halperin, present a recital of standard Renaissance and Baroque fare as well as 19th-century “German Lieder” Sunday afternoon at Clayton State University’s Spivey Hall.

“The time of the Olympic singer — higher, louder, faster — is over,” Scholl remarked when we spoke by telephone last week. “My primary task is to communicate a composition that I have not composed myself, to serve the composer using both vocal color and rhetorical tools.”

And while Scholl’s countertenor voice lacks Olympic power, it is without question an otherworldly sound that could penetrate the atmosphere of any recital hall.

Scholl began his musical training as a boy soprano in the Kiedricher Chorbuben. His voice broke at 13, but his vocal coach encouraged him to continue singing in his “head voice,” assuring him that he possessed a special gift. Now in his mid-40s, Scholl is admired for a seamless purity of sound, pervasive in his interpretations of Bach, Purcell and Handel. On the opera stage he has sung Giulio Cesare, Bertarido (“Rodelinda”) and Arsace (“Partenope”) to great acclaim.

Sunday’s recital featured several songs drawn from a new CD recording, a collaboration between Scholl and Halperin called “Wanderer,” and the duo’s musical chemistry was evident, refined in every way.

The opus includes several selections from Brahms’ 49 Deutsche Volkslieder, including “In Stiller Nacht” (“In the Quiet Night”), with a haunting text by Jesuit poet Friedrich Spee von Langenfeld. In the complete poem, a bystander recounts seeing Jesus weep in the Garden of Gethsemane before the Passion and Crucifixion. But the two strophes that Brahms set don’t specifically outline this context. Scholl’s singing was simply hypnotic as he delivered every phrase with the utmost care.

The concert began with familiar songs by lutenists John Dowland and Thomas Campion. From the start, Halperin anticipated her husband’s desire for rubato and flexibility. And Scholl’s singing was breathtaking, especially in Purcell’s “Music for Awhile,” a piece excerpted from the 1692 Dryden and Lee play “Oedipus” that features a wealth of text painting.

With a detailed introduction, Scholl highlighted a set of three Haydn songs: “Despair,” “The Wanderer” and “Recollection.” The canzonettas are settings of poetry by Anne Hunter, a late-18th-century socialite who organized cultural salons in London while Haydn was composing and conducting his symphonies there. They are rarely performed and rather instrumental in quality.

Schubert’s songs also figured prominently throughout the afternoon: the ethereal “Du bist die Ruh”(“You Are the Peace”), the angst-filled “An Mignon” and the precursor to his unfinished symphony, “Abendstern”(“Evening Star”).

After intermission, Scholl revealed himself as the ultimate storyteller in a thoughtful grouping of songs about youth and death, which included “Der Jüngling auf dem Hügel” (“The Youth on the Hill”), a dramatic tale begun with quiet, pastoral simplicity that progressed to a black cortège accompanied by a tolling bell in the piano. Finally, we heard resplendent optimism punctuated by a triple forte chord, compliments of Halperin, that resounded seemingly forever. The final lines of text read, “And as the stars came out and the moon sailed up, he read in the stars a lofty message of hope.”

It was a recital that passed far too quickly, with just one encore. Scholl gave us a preview of his upcoming pop album with a song by Israeli musician and composer Idan Raichel. Interestingly, it was an updated text setting of “In Stiller Nacht.”