No, what I said about klezmer has nothing to do with piyutim, I meant Russian shansons. About a third of Odessa, a city on the Black Sea, was Jewish. Among them were many Jewish gangsters and they were often at the forefront of the underworld. Isaac Babel wrote some very good stories about their life and mentality. In those stories is a detail I found surprisingly modern. Benya Krik, known as the King, and his friends ride through the streets (this is 1910 or so) in a fancy new red car, playing the latest hits on a grammophone.
Another thing worth remembering is that because there was a lot of poverty, Jews who could play an instrument would sit out on the streets, waiting to be hired by anyone who needed music for a party or wedding. Most celebrations, Jewish as well as Christian, featured Jewish musicians. Very interesting cross-fertilisation.

Where piyutim are concerned they usually influenced klezmer, the musicians tried to imitate the sounds of the religious singers, but it was not unheard of to sing piyutim to a popular tune.

Absolutely fine with me to discusss instrumental music.

Thanks Azizi, you're a dear. I just can't get blickies to work on this computer.

You are right that blues aren't only sadness and pain, and neither is each and every song in the genres I've mentioned. I think that what they have most in common is the tough backgrounds they sprung out of.