Wobble vs Vibrato

I am a singer and a student of singer, not a teacher of singing, but....The human voice produces a sound that varies in pitch, even when one is trying to sing a particular tone. When the variation is fast and slight, thus staying within the proper pitch as perceived by human hearing, this is experienced as good intonation. Without at least some slight vibrato, many people will perceive the tone to be lifeless and perhaps flat. One hears this sound in vocal music of the Renaissance or Middle Ages where a "straight tone" is often employed. When the variation in pitch slows down and becomes larger (greater variation between the upper and the lower frequency) this is what we call a wobble. Most people find this sound unpleasant, out of tune, even comical. Bert Lahr, for example, relied on a huge wobble in his singing to get laughs. The difference between an acceptable vibrato and an unpleasant wobble is a matter of degree or range on a spectrum. There are devices that can precisely measure these pitch variations.What causes vibrato and its ugly cousin the wobble? Breath support or the lack thereof. As the breath makes the vocal cords vibrate, there is a natural variation in the pitch which is produced. A relaxed throat and strong breath support will produce a fast, small vibrato, as can be heard in the recordings of Caruso. When the throat is tight and the breath support is inadequate to support the voice, the result is a wobble, as can often be heard in the singing of elderly vocalists. In my opinion, Callas developed a wobble after c. 1954-55 because of a loss of breath support associated with her significant weight loss. After the weight loss Callas did not ahave the muscular strength to produce her voice as she had when she weighed over 200 pounds. (You do not have to be fat to sing well.) In recordings made when she was heavy, one can hear her reinforcing the tone after she attacks, for example, a high E flat. After the weight loss she could not do this as well and the wobble gradually emerged. High notes take much more breath support than notes from the middle range and the wobble is therefore most common at the top of the range. As the body ages, it is common for breath support to diminish gradually and this causes the wobble in older singers.Jake Drake