Carstens' most famous song "Zambezi" became a world hit and has been recorded by artists such as Eddie Calvert, Acker Bilk, Bert Kaempfert, The Shadows, James Last, Chet Atkins, Floyd Cramer and Johnny Dankworth.

In the context of apartheid-era South Africa, where the everyday experience was marked by racial segregation, Carstens's music reflected a broader societal disavowal of black culture within the realm of commercial sound recording.

Titles like "Kariba," "Zambesi," and "Mombasa" referenced familiar tourist destinations in colonial neighbor states, while others like "Margate tango" and "Bosveld maan" highlighted popular local holiday spots.

This reciprocal "voicing" between vocal and instrumental practice served to both represent and deny the tabooed aspects of black culture, reflecting a broader pattern of racial disavowal prevalent in white entertainment of the time.

Through his compositions and performances, Carstens navigated the fraught terrain of racial representation, perpetuating stereotypes while simultaneously profiting from the commercial appeal of black cultural elements.