Some things that change in Black church services aren't really noticed until you think about them in a "what ever happened to" kind of way. For me, double time hand clapping is like that.

Although it's decidedly off-topic, here's a link to a YouTube video of Rwanda, East Central Africa which shows singers clapping double time:

Traditional Kinyarwanda Song Ndare and Dance - Sandra K 2002

I thought this might be of interest to this thread's readers.