Here's my question: If you're playing a diatonic harp, what is the value of blocking to get single notes anyway? I kinda like having my tongue around for other stuff.
There are a couple of reasons to use tongue blocking. Three, if you count "That's the way the Immortal Gods of Chicago blues did it, and we must imitate them or die."
The first is tone. You can get a rich tone with tongue blocking that just isn't available with a pucker.
The second is that you can do a number of chordal effects with tongue-lifts. This goes right back to the whole rationale for the invention of Richter tuning (diatonic tuning as we know it). You tongue block and plau a melody note in the middle octave, then lift your tongue to add a chord in the lower octave. Do this rhythmically, and you'll have 19th century Bavarian dance music. Do it in crossharp with bends and you'll get Big Walter Horton.
Yes, it makes it harder to a lot of the other stuff your tongue is good for. But you can still bend. And it is still possible to play rapid staccato notes. Robert Bonfiglio recently played me a set of rapid fire staccato notes over the phone, to demonstrate that it could be done with a tongue block.
Steve Wykstra writes some fine observations on vibrato, then goes on to say:
Sometimes it seems to me like my throat vibrato is tending to actually stop the air flow for a miniscule time, as well as staggering the amount of air going through the harp. This also produces some little extraneous throat noises through my JT-30. Can the glottis do the latter without any total momentary "shut off"?
Yes, the glottis can ease up a little and not work so hard. It is possible to create anything from a mild undulation to a bitten-off sob using the glottis. It's just a matter of how far you close up the air flow.
He also observes
warmth of tone, as perceived by me playing, seems affected by the distance of my cupping hand from the harmonica, and that this distance seems to vary with the note being played. I have wondered if this is just because it is bouncing back the sound to me in a certain way, or whether it is because the size of the "cavity" is crerceivable to someone listening from a diffeosition. Being lazy, I have never tested this out with a tape recorder or listener: if it is due solely to "bounce back", one would not expect to hear the difference on tape, whereas if it is a resonance thing, one would. Wouldn't one?
Yes, the effect is audible to other listeners. I'm often surprised how much, as I too expect bounceback to account for most of the phenomenon. But if it were all bounceback, then hand cupping and hand virbato would have no effect at all. I used to watch Sonny Terry do this. He'd have his free hand (the left, I think, in his case) out in front of the harp by as much as a foot, fluttering the palm in place, and you could hear the effect - the physical field is actually quite wide.
What causes this is probably a combination of several things. Damping, certainly, when the harp is close cupped. Just as the position of the tongue (forward or backward) in the mouth will bring out certain harmonics and make the tone darker or brighter, so may the hands in the sound field outside the harp. When fanning widely (as in a Pete Townshend-style windmill), you can hear a sort of flange effect, which may have something to do with the phase of the sound being changed. Perhaps this is a question for Johno.
