I've played on a YFG-812 for 16 years and I've experienced something close to this a few times as well. I read online that Yamaha used Heckel #8605 (1942) as a prototype. I'd venture to guess that they used this to develop the YFG-811 since it was the first one they produced in 1987 according to their website. By this time, I believe Heckel was using a single A flat key mechanism. The YFG-812 is supposedly modeled after a 13,000 series Heckel, but I've also read 11,000. The YFG-812 wasn't produced until 1989 and the 13,000 series Heckel started in or around 1986 making the 11,000 seem slightly more realistic from a "get one and replicate it" perspective. In either case, my having experienced the unstable "A" phenomenon debunks the hypothesis that it's related to the second A-flat key.
On my instrument, it is the low A that seems to want to "sit between the nodes" as my horn-playing wife describes it. Sometimes i notice it on the top-line A, but not usually. It's possible that it blows into the next octave, but maybe I've just adapted over the years. Whenever I notice this, it's either time to scrape a bit more reed in the area south of the "eyes" of the reed, or to check the height of the low G pad cup. Betsy Sturdevant, Columbus SO, posted a piece on her blog about the critical importance of the height of this pad to the intonation and stability of the notes in the boot. I find this to be "bang-on" advice and nodded in agreement the whole time I read her post.
I also find the low A instability worse with poorer bocals. I've been through lots of bocals trying to change a bassoon with a thick wall and a "rich authoritative sound..." into one with a "greater degree of flexibility..." in other words, trying to get this tank of a bassoon to play more delicately in a pp section, a continuo part or a ww5- a fool's errand, I'm sure. What I've noticed with the unstable boot notes is that the bocals that overblow their harmonics in tune are generally more stable on the low A and that the bocals whose harmonics overblow out of tune are potentially more unstable on the low A. I just bought two new bocals to add to my growing collection and neither seem to be unstable on the A.
My local Yamaha dealer has a brand new YFG-821 in stock and I'm going to go try it out compared with my YFG-812 and I'll report back if I notice the same phenomenon. I've probably played about ten Yamaha bassoons over the years when I've run into them but I didn't notice this as a Yamaha-specific quirk. I'd love others with more experience with Yamahas to throw in their two cents.
Last edited by 6bassoon9 (2013-01-04 08:47:42)