The KKK is, or used to be, an odd mixture of clandestine organisation and social club. Organisationally, at any rate, if you can imagine a combination of the Masons and the British Legion, you're probably not far off.

As far as its public persona is concerned, the KKK has had a long association with country music and various country musicians, including Fiddling John Carson and Al Hopkins and His Buckle Busters are known to have played for dances organised by them. The KKK also used to draw on the services of black musicians and even acted as manager for at least one blues singer. (Sorry. I can't remember who.)

For that matter, there's a bizarre story related in Screaming and Hollering the Blues about how Charley Patton was virtually kidnapped and taken to perform for a white audience.

I'm not so sure about developments since black emancipation. However, there is still an unhealthy vein of racism in country music,(see especially the recorded output of Johnny Rebel (real name Clifford Joseph Trahan) who recorded such corkers as Nigger, Nigger; Nigger Hatin' Me and Move Them Niggers North)and doubtless it's country music that the KKK listens to.

I'd be very surpised if there isn't a body of song which the KKK sings at its clandestine meetings. But it has never, as far as I know, ever been discovered, and I think for fairly obvious reasons.