rarescale is a flexible-instrumentation contemporary chamber music ensemble, which since its formation by Carla Rees in 2003 has gained an international reputation for its work promoting and creating new repertoire for low flutes.

The group performs regularly in the UK and abroad and works in close collaboration with a wide range of composers. UK performances have included the group's own annual Premiere Series in London, recitals in Birmingham, Leeds, Manchester and Sheffield and appearances at the Huddersfield Contemporary Music Festival, Dartington International Summer School, Edinburgh Festival Fringe and at the UK Microfest Festival of Microtonal music. Performances in the USA include at the Sonic Circuits Festival in Washington DC, Spark Festival in Minneapolis and recitals in New York, Los Angeles and San Francisco. The group has also performed throughout Europe, including in Germany, France and Greece, and is a regular vistor at international flute festivals, including in the UK, USA (National Flute Association), Switzerland (La Côte Flute Festival) and France (Flute Festival Provence).

Also committed to the education of both performers and composers, members of the group have also given workshops and masterclasses for the National Youth Wind Orchestra of Great Britain, as well as at universities and music colleges in the UK and USA, including most of the UK conservatoires, and at the Juilliard School, Manhattan School of Music, University of Southern California and UCLA.

In 2007 the group expanded further to incorporate rarescale Flute Academy, a training ensemble for university level flute players to enable them to learn about performance techniques on the alto and bass flute and to gain arts management experience. With a building international profile, this rarescale Flute Academy has performed in the UK, Greece, USA and represented the UK at the European Flute Council Flute Ensemble Festival in Poznan, Poland, in April 2019.

A professional flute ensemble, the rarescale Kingma Ensemble, was formed in 2019 to develop chamber-sized repertoire for flute-based ensembles in collaboration with a wide range of composers.

rarescale runs educational events for composers and instrumentalists, records for its own label, rarescale records, and many of the works composed for the ensemble are available through Tetractys Publishing.