You may get a very bluesy sound with common accordions and melodeons as used in zydeco tunes for example but with *our* concertinas it IS quite tricky whatever method is used to get the weeping raw tone you mostly want with blues I am afraid. The singular concertina reed set gives a too clean or dry sound compared to the wet accordion/melodeon tuning .On Youtube you find quite a number of samples by melodeon or accordion players and there have been several successful recording artists but I haven't come across anything with a concertina. Someone who has?