Per questa bella ariaaaa???????? ROTFL Maybe this is "Per questa bella mano". It was not written for the double bass but for the Wien violone, 5 strings, fretted, tuned DD AA D F# a. On this instrument it is quite simple to play it. Nothing to deal with the modern double bass. He plays also the Rigoletto solo in 6/8 but it is written in 4/4... simply delirious... for those who understand italian even more.