Thank-you Quetscher, It’s a relief to know it’s not just my 36 that was failing. I was a little afraid I had got the back plate on wrong. :-/
What I’ve noticed is the distance from the instrument seems to make the problem worse. Playing through a tube with an improvised connector mainly wrapping vinyl tape around the hose till it fit the diameter. I really can’t get much tone and have to take a new gulp of air for almost every note in the low register. The angled mouthpiece works fine for the first two octaves but the lower notes go wildly flat and the low G actually makes a sort of braying sound like a blues harmonica player might covet. The trumpet mouthpiece is better but there is still some flatting on the low notes and finally blowing directly into the body of the instrument it seems to play fine. I hadn’t noticed before but It seems most of the players I’ve seen using the Piano-36 seem to be blowing directly into it. I had thought this was just a matter of personal taste or losing the mouthpiece but now I’m wondering if they had the same experience?
Don’t know if the images posted?