I have that problem a lot on the low end of my tenor. It is definitely me, not the horn. When I think about opening my throat and putting more air into the horn, it doesn't happen.
Edit: More info-I had this same problem when I first acquired my curved soprano. It would warble some on low D, and a lot on low C. I had the mouthpiece pushed very far on the neck to get the pitch correct according to my tuner. After reading Paul Coats article on soprano intonation here on SOTW, I eventually had the mouthpiece further out after getting used to the horn through practicing. I'm playing in tune, and the warble on the low end stopped.
Try moving your mouthpiece back and forth on the cork to see if there is a spot which reduces the warble while still being reasonably in tune. Then give some good air support on the notes which warble, and try different tensions on your reed. With practice, that warble will go away.
Edit: More info-I had this same problem when I first acquired my curved soprano. It would warble some on low D, and a lot on low C. I had the mouthpiece pushed very far on the neck to get the pitch correct according to my tuner. After reading Paul Coats article on soprano intonation here on SOTW, I eventually had the mouthpiece further out after getting used to the horn through practicing. I'm playing in tune, and the warble on the low end stopped.
Try moving your mouthpiece back and forth on the cork to see if there is a spot which reduces the warble while still being reasonably in tune. Then give some good air support on the notes which warble, and try different tensions on your reed. With practice, that warble will go away.
