They freely confirm that they owe their creation to a video that suddenly went viral on YouTube. It showed them as a group of Indiana University students having a ball as they created beautiful music with nothing but their voices.
And, for all the subsequent success of Straight No Chaser, this talented group of acapella singers give all the air of freshmen goofing around as they sing for the sheer joy of it.
In essence, that’s exactly what they do - and clearly in the process they have as much fun as the audience does.
But beneath the musical mirth lies an extraordinary combination of voices and movement that make for a hugely enjoyable show.
I’d gone expecting a set based largely on old classics, but Straight No Chaser’s repertoire spans the eras, with Lady Gaga, Oasis, and Madonna reprised alongside the likes of Frankie Valli and the Four Seasons, the Beatles and the Rolling Stones.
Those latter two were combined to wonderful effect as the nine-strong group split for a perfectly co-ordinated simultaneous rendition of Angie and Help! (Try doing that at home - it isn’t as easy as it sounds!)
This was the last leg of their British tour but if they return, catch these swell acapella fellas if you can.