I've been exploring vibrato with a lot of my students recently, and through teaching it I finally feel as though I have an intellectual grasp of what I'm doing. It actually took years of teaching before I really dared to approach vibrato (and even more before I started talking about embouchure). I've headed down too many blind alleys and found myself in too many tenuous corridors when I started talking about those invisible, semi-mystical aspects of wind playing. But now I have my schtick down and I've talked about it with enough people using enough different words that I feel pretty confident that I know how to teach vibrato.
The paradox of vibrato is that although the pulsation adds intensity to the sound and the line, you have to create it by relaxing more than usual. To play a supported line without using vibrato means to be right up against the resistance of the oboe all the time. It's almost impossible to add extra energy to that sound without overblowing and forcing in an unhealthy and unattractive way. I don't like to think of the vibrato going downward from the main note - that sounds sloppy and lazy, and leads to bad habits. Therefore, I let my main note be a little undersupported so that there is room to add vibrato on top. The more intense the effect I am trying to create, the less real note there is between the peaks of the waves. Hence, the difficulty - since I'm no longer blowing directly into the phrase I have to shape the line more with the vibrato itself than with the air, and suddenly I'm one more step removed from naturalness. In an ideal world, when I'm playing well and regularly, this process doesn't take a lot of thought. I can phrase with and through the vibrato with ease.
Here's the thing, though - I kind of think I've analyzed it so much lately that it doesn't seem quite natural to me anymore. Even though I've played several orchestra concerts already this season, I still feel a little new at the oboe since having Zoe and taking time off. What worries me for this weekend is Wagner's Siegfried Idyl, a piece I've played many times before. It's very romantic, but not merely thick and lush like the Rachmaninov Piano Concerto we played a few weeks back. There's a lot of delicacy to it and I feel that as I practice I'm overvibrating and pressing in an unattractive way. I'm overthinking my vibrato and sound, in other words, mainly because I've been overthinking everyone else's for weeks now without playing enough myself.
I hope and trust that in context, when I'm surrounded and inspired by my great colleagues and the music is flowing around me, it will be like riding a bicycle. I'll be playing what I hear in my head without stress and strain and without having to separate the sound from the vibration from the phrase in my mind. That when we start the magic will happen as it always has before. I'm putting a lot of trust in my past base of years as a professional musician. Because I can't put in the time I wish I could right now I am leaning on my base in a way that surprises me - and so far it has not let me down.