It don’t mean a thing,

Some formulas just shouldn’t be messed with but in the world of music, such formulas are subject to whimsy.

Take 8 1/2 Souvenirs. One of the most dynamic swing bands around, the group’s line-up in the last two years was a vertible brew of expert musicianship. Pianist Glover Gill and his spidery hands vied for as much stage presence as consumate leader Olivier Giuraud and mesmerizing singer Chrysta Bell.

Happy Feet, the group’s thrice recorded debut, documented the volatile chemistry of the Souvenirs.

On Twisted Desire, 8 1/2 Souvenirs loses Glover and drummer Adam Berlin. The resulting sound doesn’t swing as much, and Glover’s huge piano performances are greatly missed.

Excellent bands get beyond such loses, but on Twisted Desire, the remaining Souvenirs can’t seem to fill the void. Bell, her voice an excellent instrument, seems a too bit dreary for the Souvenirs’ usually buyoancy. And Giraud, himself a charismatic singer, takes to the mic only twice.

New drummer Rob Kidd doesn’t swing like former drummer Berlin, and it’s tough to reconcile the Souvenirs’ jazz with Kidd’s more rock ‘n’ roll thumping.

Twisted Desire is 8 1/2 Souvenirs’ second album for a major label, and its third overall. Still, consider it a case of sophomore slump.