Voice + double bass = irresistible groove. The musical partnership between Berlin singer Martina Gebhardt and bassist Robert Teigeler is based on this simple yet effective formula. Whether original compositions, cover versions or jazz standards - what the two of them touch on their album "Bass Groove Ballads": they grab the listeners from the first bar. Because the spark immediately leaps over and the duo "almost hypnotically" captivates their audience. This is how Hildegard Knef's friend of many years - the theatre director Axel Andree - puts it in the liner notes to the album.Voice and double bass - a rather rare combination in the music scene, in which the boundaries are largely sounded out. For such an instrumentation requires many qualities if it is to function. Technical class, refinement, adaptability - and above all: the courage to use the available freedom. "When Martina came up to me with the duo idea, I found it highly adventurous at first," recalls Robert Teigeler, who really is not lacking in experience. He has known the German jazz and pop scene for more than 30 years. A long period in which he not only made a name for himself as a sought-after session musician, but also as a producer.