Unless you have one of those Model M2 Marigaux instruments with the tiny top joint, middle G is just an awful note because of how the oboe is put together and where the join lies. My middle G is almost always flat and dull-sounding, which makes this moment in the 2nd Oboe part from Strauss’ Don Juan absolute torture to play:
You have three bars’ rest before you come in, and the sf on the F makes it a little easier, but then you have to dim. down to pp while moving up to a G, and this is gruesome. If you do manage to hit the G in the middle, chances are it will sag as you try to maintain the pp. I only managed to play the G in tune once during rehearsals and it came out resoundingly flat in the concert – happy times! But my teacher has since told me that if you put the F key down when playing a G, it sharpens the note a little and gives it a slightly more steady and pleasing tone:
This does work on my oboe, but the difference is very slight and it’s fiddly trying to get to the F key without depressing another key by mistake. Even so, I wish I’d known this before playing the Strauss, because it would have been easy given that I was already playing an F – all I had to do was leave my third finger down! – but in trickier passages, this fingering is possibly just too fiddly to be feasible.
There is an alternative, however. If you don’t have a B to C link on your instrument, the B/Bb keys are marvellous for this sort of thing. Playing a G with the B/Bb keys depressed means that, on my oboe at least, the middle G will almost be in tune – hooray! – and with a little bit of lipping up, that’s job done. I’m not suggesting you use this fingering every time, of course, but it’s a useful tip if you’ve got something like the Strauss on your hands, or the infamous Ds to Gs in the first of Nielsen’s Fantasy Pieces for Oboe and Piano:
Nasty. But not as nasty as…
But that D-G leap is easier if you put the B/Bb keys down.
And in fact, when playing a bottom Bb, always put the B key down as well if you can. It increases your chances of actually getting the note to sound.
The B key can help on the cor too, in steadying the bottom D. The bottom D on my cor is a bit sharp, but if I put the B key down, D comes out in tune every time. And that’s what you want, really.