The music industry may be preoccupied with charts and categories, but some musicians defy classification. Trumpeter Kenny Wheeler and singer Norma Winstone, both of whom have new releases out, are two examples of talents that resist all manner of charts, graphs, lists — and even maps.

In the case of Kenny Wheeler, it is difficult to say what kind of jazzman he is — bopper, avant-gardesman, big band player. And it is equally difficult to classify him in terms of nationality. Mr. Wheeler was born in Toronto in 1930, but he came of age musically in the busy London jazz scene of the ’50s. He first recorded with a swing band that was modeled on Count Basie’s band, and he achieved prominence with the modern-minded British composer-orchestrator John Dankworth. By the mid-’60s, he had become a founding member of the Free Jazz movement in England, and then achieved an international reputation in the United States as a member of Anthony Braxton’s quartet.

Although he is one of the living masters of free-form improvisations, he is also a highly skilled composer who knows how to play and write both with and without form. He has composed a succession of stunning large-format orchestral jazz works. His collaborators have included major icons of contemporary jazz — in every instrumental format. He could turn up in Montreal in front of a big band, in New York to record with an all-star quartet, or in Düsseldorf as half of a duet of living legends.

For a creative musician who works in so many different areas and locales, the instrumental format is the same as the compositional concept. It’s all about seeing what kind of music can be devised for, say, the group that played on his previous album, “It Takes Two.” That album included a quartet of two guitars (including John Abercrombie) and a bass in conjunction with his trumpet. On his new recording, “Other People” (CAM Jazz), Mr. Wheeler uses a format that is new for him: a string quartet (of sorts). Most of the album features a combination of four strings, trumpet and flugelhorn, and Mr. Wheeler’s longtime piano partner John Taylor.

The most interesting point regarding this music is that it is nearly impossible to tell that it was written by a famous jazz musician experimenting for the first time with a traditional classical format. It sounds more like a contemporary classical composer writing a chamber work that incorporated jazz elements, specifically the solo trumpet and piano. The combination of piano and solo violin opens the first movement, playing ad lib before the trumpet and the other three strings come in and the work shifts into a brisker tempo. There’s a passage by trumpet and piano before the strings slide in.

Some of the pieces are brisker than others: “The Lucky Lady” is more upbeat than “The Unfortunate Gentleman” (fittingly). But the overall feeling is more classical than jazz — and a very somber kind of classical music at that. There’s even a completely composed piece for the strings alone, titled simply “String Quartet No. 1.” But even though the music isn’t light — and certainly not a load of laughs — it is indeed lyrical and highly compelling. Mr. Wheeler has found an entirely new vehicle for both his melodic writing and his tart-and-tangy brass work. I doubt this will be the last time he employs it.

The same is true for Norma Winstone, whose new album uses the unusual format of voice, piano, and saxophone. Ms. Winstone was originally known as one-third of the trio Azimuth, a prolific and high-profile group that played in the 1970s and ’80s. She co-starred with Mr. Wheeler and Mr. Taylor, who was then her husband. One of the major jazz-based singer-songwriters on the international scene, Ms. Winstone can be constructively compared to several artists. Her eclecticism and engaging use of wordless songs recalls Sheila Jordan. Her superior songwriting skills are the equal of Abbey Lincoln. And her knack for erotic detachment — which comes through on the new album during Cole Porter’s “Every Time We Say Goodbye” — suggests the style of Helen Merrill.

Even so, just like these iconic American singers, Ms. Winstone has a creative universe all to herself, one that has a lot in common with that of Mr. Wheeler. Most of the original compositions (even her reinterpretations of existing music) proceed in the same loping, amorphous tempo — reminiscent of Nino Rota’s themes for Federico Fellini movies. (Mr. Wheeler played on a 2003 album of Fellini music with the Italian pianist Enrico Pieranunzi). Her most famous composition — the one performed most by other singers — is her lyric to pianist Jimmy Rowles’s “The Peacocks” (retitled “A Timeless Place”), which can seem surreal and spaced-out. It is perhaps no wonder the album and lead-off track are both titled “Distances.” As in her work with Azimuth, her current work uses a trio that includes her voice and piano (Glauco Venier), but instead of a trumpet, there’s the German reed player Klaus Gesing, who switches between various saxophones and clarinets.

In the same way that Mr. Wheeler incorporates both free improvisation and traditional melody-and-chords music, Ms. Winstone is equally versed at singing songs with or without words. The music sung without words is found on the tracks “Gorizia,” which is like a nonverbal moan, and “Ciant,” which might as well be a scat number, at least for those of us who don’t speak Italian. (Credit for the later is attributed to classical composer Erik Satie and Italian movie director Pier Paolo Pasolini.) “Giant’s Gentle Stride,” as the title suggests, sounds like a paraphrase of John Coltrane.

The track that most floats my boat is her radical post-Katrina revision of “Here Comes the Flood” from British glam-rocker Peter Gabriel’s first solo album in 1977. Mr. Gabriel belted it like a power pop ballad, with a choir-like effect on the song’s hook, but Ms. Winstone makes it intimate and apocalyptic at the same time. She is aided on that track by Mr. Venier’s distant, left-of-center keyboard accompaniment, including strums inside the piano and equally original reed obligati (mostly on bass clarinet), both of which suggest the state of floating in the deluge.