As My treat to myself, just after Christmas I bought a new Besson Sovereign cornet. As most will know they are now being built by the French company Buffet/ Courtois and are supposed to be the bees knees. However I am now finding problems with its tuning since the start of the new years rehearsals, It may sound OK to me on its own, but when played with others, some notes are quite definitely out, either higher or lower depending on which note and the valves used. Has any one else recently bought a new Besson and suffering the same problems? Or is it me and perhaps choice of mouthpiece or other issues.