Mastering classical voice means mastering [a], or ah as it is more commonly known: that's what Francesco Lamperti and Manuel García thought anyway. I was reminded of that this morning when I practiced after breakfast, recording my singing on my Imac with Garageband. (Hello! This is what singers do!)
There are many times when we think we are doing the right thing when, in fact, we aren't doing it at all, which is the circumstance I found myself in this morning. My [a] was rather iffy, not chiaroscuro enough, which is what the recording revealed. Not enough flattened tongue and arched palate in my case. How long did it take me to figure things out and correct matters? About 20 minutes. Time well spent if you ask me.
Here's the rub. It's easy to lose one's way thinking: "Oh yeah...I learned that and don't have to do that again." I can't tell you how many times I have heard this thought expressed in the studio in one way or another, the student intimating that just because they've accomplished [a] once they have it for life. If only singing technique was a product which could be bought and stored on a shelf! But it doesn't work that way. Mental knowledge and kinesthetic knowing are two different things. What you think you know and what you actually know aren't the same thing. This is why I tell students the mirror and recording don't lie. You can learn an immense amount from both and neither will cost you a dime. The voice needs and wants this constant attention.
The voice is like a wall: you have to take care of the cracks or they will get bigger and eventually the wall will come down.
Lamperti called [a] the father of vowels, while my own teacher taught that it was the "position for singing." Both were talking about he same thing, I believe.
Here's one thought for mastering [a]: the 'control' panel is under the tongue, right behind the tip.