Monday, October 18, 2004

Resonance, Take 2

Tonight in voice class we all ran through abbreviated, one-minute versions of our presentations and it was really interesting to see how much everyone improved. It's fun to see what a difference a week or two can make, and it's also fun just to be paying attention to the subtleties of speech that we're not usually aware of. I think I did rather better myself, and I certainly got some good feedback, though it's hard for me to really tell how I sound when I'm also concentrating on the actual content of what I'm saying. But I've been practicing a bit and I guess it shows. The way I practiced was to start with just singing in my car, with the sing-along playlist on my iPod. It's a lot easier to notice resonance and vibration when singing because the sounds are more sustained, and it's easier for me to relax and make a bigger sound when I'm in my car and singing along with something. So I did that for a while and just started paying attention to any vibrations I could feel in my chest and head. And then when I went back to practicing what I was going to say, it was easier to get that feeling in my speech as well. So that was good.

One thing I was a bit disappointed with tonight though, was when I asked the professor about pitch production. I'm really curious about the actual mechanism that changes pitch, and I was expecting to learn about it in the class, just like learning about diaphragms and resonating areas and all that, but unfortunately she doesn't really know the details of how it works. One of the medical people in the class explained a bit about the vocal cord setup, which was good, but one big thing I want to know about is what affects vocal range, and she couldn't tell me that. I understand some stuff about vocal chords -- like changing the tension to change the pitch -- because it's just like musical instruments. But I don't understand how something like testosterone would make men's voices lower (I've never put testosterone on my fiddle to play lower notes). And there must be something else that affects vocal ranges across different people, since I assume most people's vocal chords are approximately the same size and tension. I guess I'm going to have to go get a book on this or something.

Knowing more about the vocal chords would probably help with figuring out more about Tuvan throat singing, too. Especially with the subharmonics, which I don't know how to do at all (I can kind of do the overtones a bit, but that's an entirely different technique).


Lacey said...

Yes, I know this is a long comment, but I thought it might be interesting to share.....

I took a class at Stanford three years ago called "Biology and the Evolution of Language." Your questions about pitch and vocal range sounded really familiar, so I went and dug up my old notes (unfortunately, I don't seem to have the books anymore -- darn!) Some notes that seem relevant are the ones talking about vocal cords, and how they're not really cords, but folds. Air from your lungs vibrates the folds and causes speech. My notes say that men's vocal folds go through about 100 open/close vibrations per second (100 Hz), women 200 Hz and children 400 Hz. These are called "fundamental frequencies", the lowest frequency a person can generate, and also the strongest and therefore loudest. You can produce multiples of the fundamental frequency, called "partials," but the fundamental is base (or bass?) that's always present. This could very well account for men tending to have lower voices than women.

Another factor is of course the length of the vocal tract, which is an average of 17.5 cm long in adult males (I don't seem to have the figure for females, but I know it's shorter). Simply the length of the resonating tube will have an effect on the resonating frequency of the sound that comes out, so that probably explains the lower fundamental frequencies of men's voices. I don't seem to have any mention of testosterone as a factor.

I don't seem to have any notes on vocal ranges specifically, though I haven't thoroughly scoured my notes. I also don't know how you would relate this your stringed instruments, as I don't play one and my brain isn't awake enough to come up with an explanation. I did find a note on throat singing, saying that if you can lower your larynx, your fundamental frequency drops so you get a really low fundamental and a really amplified formant (multiple) that are heard as two separate notes. You can then (somehow) control your vocal folds and use your tongue and jaw to increase the resonance of the amplified frequency, and there you go. Or something. :) It's like voicing into a didjeridoo, but without the second, external tube because you're doing it all inside.

I don't know if this is anything resembling helpful (or even interesting) to you, but I got intrigued by it all over again so I thought I'd share it. I can always copy a bunch of these notes for you if you want to go through them yourself. :)

Tandava said...

That is interesting. And I do remember about the vocal folds, but I guess it's just convenient to think about cords in terms of changing length and tension to change the pitch. I still don't understand why men and women would have those different fundamental frequencies you mentioned, though that was a difference of an octave, so it does seem about right. Maybe men have thicker vocal folds, like thicker guitar strings make lower notes?

Also, I'm unsure about how the length of the vocal tract would relate to the pitch. I know that longer tubes make lower notes, but wouldn't the vocal tract be proportional to your overall body size? And if so, then why is it that I can point to someone with the same body size as me but a much lower bass voice, as well as a considerably taller person who's a tenor?

I'd certainly be interesting in seeing any of your notes that you still have on this. And if you can recommend any of the books from that class, that might be good, too.

Do you have any tips on how to lower my larynx? :-) I think some forms of throat singing also involve vibrating the false vocal folds and, as you said, increasing the resonance with your mouth, etc.