Their concerts brought them already to Austria, Germany, England, Italy, Israel, Holland, Switzerland and the United States, to the prestigious halls as there are the AUDITORIUM DI MILANO, the CARNEGIE HALL WEILL RECITAL HALL and Radio(e.g. RAI Radio3, KolHaMusika )- and TV-transmissions in Israel and Italy.

Known composers – Riccardo Jehoshua Moretti (Italy) , Ella Milch-Sheriff (Israel), Ronen Shapira (Israel), Daniel Galay (Israel) Emanuel Vahl (Israel) and John Rose (USA) – dedicated compositions to the String-Duo Halaf-Langheim.

2008 their first CD was released with Romeo Records and received excellent reviews of international music magazines (BBC MUSIC MAGAZINE: „Appealing programme from the string duo, a rewarding partnership…”

GRAMOPHONE August 08: "the delicacy of their playing creates a magical atmosphere." MusicWeb International Aug.08: "played with such enjoyment and style that it is irresistible.“,

AMERICAN RECORD GUIDE Aug.08 "the liveliest, most colourful performance") and was already broadcasted by radio stations like Kol HaMusika(Israel), Bayern 4 Klassik, and SWR2 in Germany.

Except their String-Duo activities this two musicians appeared also in other chamber music groups with concerts at the Wiener Konzerthaus, Wiener Musikverein, Alte Oper Frankfurt and the ORF (Austrian Broadcasting Corporation).

Currently they co-operate with the orchestras of La Scala, Filarmonica della Scala, Orchestra Sinfonica Nazionale RAI (Italian Broadcasting Corporation), the Symphonica Toscanini (Lorin Maazel) and the "Opern und Museumsorchester Frankfurt".

Langheim was the principal viola of the Orchestra Sinfonica di Milano G. Verdi chosen by the conductor Riccardo Chailly, where he was presented in many radio transmissions also as soloist. Furthermore he co-operated also as guest principal viola with the BBC National Orchestra of Wales and currently as guest principal viola with the Royal Liverpool Philharmonic Orchestra and as chamber musician with the Ensemble Midt Vest in Denmark..