Nadav Masel is a classically trained double bassist who moved into free improvisation as an adult after a period of formal study in Berlin. He studied classical bass at the Universität der Künste under Prof. Michael Wolf, and it was through Wolf that Masel took a temporary job as an usher at Bassfest, an international bass convention held in the city. A masterclass on bass overtones given there by Barre Phillips reoriented Masel's whole approach to the instrument: hearing the double bass explained as a resonating box rather than a tool built for a fixed technique, he arrived at the idea that "every sound this instrument can make is a good sound." He took about a month away from playing to absorb the lesson, then booked his own first solo improvised set and began the career he has followed since.

By the mid-2010s Masel had become one of the more visible free-improvising bassists in Israel's Tel Aviv scene. His main working group was the Hanut Trio, with guitarist Ido Bukelman and drummer/percussionist Nir Sabag, named for Hanut ("shop" in Hebrew), a Tel Aviv theater-gallery at 31 Aliyah Street that hosted their concerts. The trio's self-titled album was recorded April 26-27, 2014 at Teiva Studio in Jaffa and released June 15, 2015 on OutNow Recordings, the Brooklyn/Tel Aviv free-jazz label run by saxophonist Yoni Kretzmer; Masel plays double bass and Moroccan flute on it. On the same release date, OutNow also put out Ground Birds, a duo with Bukelman recorded live at Barbur Gallery in Jerusalem on May 23, 2013, with Bukelman on banjo, acoustic guitar and bells against Masel's double bass. Both records grew out of years of Tel Aviv free-improv concerts and ad hoc collaborations, including sessions with the Polish reed player Mikołaj Trzaska and the Israeli clarinetist Harold Rubin.

That Rubin/Trzaska connection produced its own recording: Ten Chamber Kingdoms (Jazzis Records, 2014), a ten-piece trio session billed to Rubin, Trzaska and Masel, with Rubin on clarinet, Trzaska on saxophone and Masel on bass. Polish reviewers described it as more lyrical and poetic than Trzaska's rawer duo and trio work elsewhere, an "unusual meeting of musicians from different worlds" built from dialogue between the two reed players over Masel's bass. Masel also carried his bass work into the classical world, serving as a bass player with the Israel Contemporary Players (Ensemble21), the country's leading contemporary-music chamber ensemble, founded in 1991 by the composer Dan Yuhas. In October 2015 he made a rare appearance abroad, performing solo and in a trio with the German cellist Ute Kanngiesser and the London bassist Tom Wheatley at the Hundred Years Gallery in London, where he was also described as working with hidden electronics and vocal sound in his solo sets.

Masel's connection to the saxophonist Albert Beger comes by way of Good Morning Universe (NoBusiness Records, NBEP 4), a 10-inch EP recorded at Levontin 7 in Tel Aviv on February 17, 2017 and released in an edition of 300 in 2018. The record is not a Beger album: it is billed on Discogs to the bassist Shay Hazan alone, and all four compositions are his. Beger is nonetheless part of its six-piece personnel, on tenor saxophone alongside a second tenor player, Eyal Netzer, while the drum chair is shared by Ofer Bymel and Haim E. Peskoff. For this session Masel set aside the double bass for "Hamsa," a custom five-stringed cello, credited album-wide in the release's personnel block. Outside jazz, Masel plays contrabass on Cisterns (Raash Records, 2023), the closing release in Asher.Zax's political sound-art trilogy The Catastrophe, a setting of a poem by Tal Nitzan for voice, electronics and a small ensemble of guest players.

Masel's playing sits at the meeting point of classical technique and free improvisation: his training in Berlin gave him a physical, overtone-aware relationship to the bass that he carries into fully improvised settings, where he has said the sound and feel of the instrument matter more to him than melody or harmony in the abstract. That range let him move between the ametric, texture-first duo and trio work of Ground Birds and the Hanut Trio, the more composed chamber writing of Ten Chamber Kingdoms, and a parallel life as a bass player inside a conventional contemporary-classical ensemble. Willingness to reach for an unconventional instrument when a session called for it, most visibly the custom five-stringed cello he played on Shay Hazan's Good Morning Universe, is characteristic of a player more interested in the widest available palette of bowed-string sound than in any single fixed role.