free-blowing
/ˌfriːˈbləʊɪŋ/adjective
1That blows freely.
2Of a wind instrument: that readily allows the passage of air, or easily produces (a clear) sound.
3Chiefly Jazz. Of a musician or ensemble: that plays music (especially on a wind instrument or instruments) in an unrestrained, unstructured, or improvisational style.
Origin
Mid 18th century. From free + blowing.