Hi. I finally found ONE soprano sax in the local stores, and tried it out. It was a Keilworth, selling for about $800, somewhat used, and I had to point out that the low bflat key didn't even close. However, that's beside the point.
Playing the c (in the middle of the staff) was horribly out of tune with the d just above. I had to lip the d way down and the c up to make them in tune relative to one another. Is this a common problem in Sopranos, or was it just that particular horn?
I have a similar problem. I've adjusted my mouthpiece almost all the way in in order to play D2 and higher in tune. My lower octave is a half step flat. I've actually had to play songs in two different keys on occasion.
My set-up is a early 70's Super-Dynaction Soprano with a Dukoff 8* STM.