Among those who wrote for her were Lennox Berkeley, Arnold Cooke, Roberto Gerhard, Elizabeth Maconchy, Peter Racine Fricker, Alan Rawsthorne and Mátyás Seiber.
After an early recital in London in 1927, The Times said, "Miss Wyss has some pleasant notes in her voice, but the tone was tight in the upper range.
The Times said that Wyss "possesses a soprano voice of an exquisitely yielding quality ... a singer so completely satisfying that we would not trust ourselves to say how much of the pleasure we derived from her performances was due to her or the music itself.
[3] The most famous work that resulted from this was Britten's Les Illuminations to words by Rimbaud, which Wyss premiered in London in 1940 with Boyd Neel and his orchestra.
[17] However, by 1942, Britten's knowledge of voice and vocal technique had greatly increased, and he preferred Peter Pears's interpretation of Les Illuminations to Wyss's performance, which he described to a close friend as "hopelessly inefficient, subjective & (of all things) so coy & whimsey!!!
[21] Wyss gave many first performances of works in French or English by composers including Lennox Berkeley,[22] Arnold Cooke, Roberto Gerhard, Elizabeth Maconchy, Peter Racine Fricker, Alan Rawsthorne, George Enescu, Antony Hopkins[23] and Mátyás Seiber.
[3][4] She was also a leading exponent in the UK of songs by Gabriel Fauré, Claude Debussy, Reynaldo Hahn, Maurice Ravel and other French composers.
[4] During a career that lasted until the early 1960s Wyss broadcast extensively for the BBC, and made concert tours in continental Europe and Australia.