Been playing for 37 years Tony, and I never liked standing still. If
there is such a thing as 'diaphragm' vibrato, I've never heard it or
seen it. The hands can make what is probably better described as a
tremolo, as can the tongue; these practices produce a variation in tone
and/or volume (and when I say' tone', I am referring to bass & treble
variation, not 'pitch' - by which I mean fluctuations between flatness
and sharpness)
A true 'vibrato' (rhythmic variations in pitch) is produced by the
opening and closing of the vocal chords (read 'epiglotus' if you want)
I am no great shakes as a singer, but when a 'vibrato' occasionally
appears in my voice, I think it is a variation on this process, but
still caused by movement of the vocal chords: If my diaphragm is
controlling the flow/pressure of air, my vocal chords can be relaxed
enought to viabrate according to the frequency of the note to produce a
vibrato.
With the harmonica it is a slightly different process: it is not the
vocal chords themselves that are making the sound but the reed in the
harmonica. Hence the function of the vocal chords is not to flex and
unflex to change their own pitch, but to act as a shutter to cause
sudden build-ups of pressure followed by equally sudden
release/decrease. Naturally, the diaphragm retains its importance in
keeping a constant 'demand' for air (I could say 'pressure', but the
pressure varies with the stopping of the epiglotus) but any viabration
felt there is a result of the 'glottal stops' (choking of the epiglotus
or vocal chords)
This is all a re-phrasing of Tony's conclusions, which have been well
observed and considered.
Reading over what I have just written, I realise that I have used the
word 'demand' (ie as opposed to 'supply' as in blowing) when talking
about the role of the diaphragm in the production of vibrato.
Hmmm...this opens up another matter all together: vibrato while blowing,
not drawing....does it exist?
Obviously not, on holes 1-7, because there is no appreciable pitch
variation available (ie the blow notes don't bend)
I do attempt to use the glottal stops (hiccups, chuckles, coughs or
whatever) on blow notes, but they act more like 'tremolo', and I am not
aware of ever really making the same process work on the blow-bend notes
(8,9,10)
It just doesn't seem to be appropriate on the hight register notes. I
use a kind of harmonic trill, a la Gwen Foster, which gives a wide
variation from one semitone to another,; but they are two separate
notes, so it is not really 'vibrato' as such.
I have not yet tried a blow vibrato on the lower two octaves of an XB,
but I intend to experiment as soon as I get away from this desk!
Cheers,
RD
>>> Tony Renshaw <tonyrenshaw268@xxxxxxxxxxxxxxx> 3/03/2007 12:33:18
>>>
As a three year player who has heard lots about vibrato and the way to
create a deep, melodious one using my diaphragm, I would like to
challenge
explanations I have been given with my own conclusions, and wait to get
torn apart. Simply, it has been explained to me that the diaphragm is
the
key to a deep vibrato. I believe this, but it has historically been
described to me in isolation. I believe, for me anyway, that the only
way
to get a good diaphragmatic vibrato is to use it to create a "back
pressure", or area of "negative pressure", using your epiglotis. In
isolation one can argue that it is all about the diaphragm, and to
create
such a "negative pressure", it is. The problem I have is that I can use
my
diaphragm, that big muscle for prolonged periods, but generally only in
one
direction or the other. I certainly can't "vibrato" it. To try and do a
deep, rhythmical vibrato from the diaphragm with a completely relaxed
throat and mouth is damn near impossible. I am persistent though, so if
enough people convince me of the error of my ways, I will conquer this
diaphragm issue, if in fact it is the way to go. So, in conclusion, in
my
narrow and short experience, I believe the vibrato is a combination of
a
"negative pressure" created with the epiglotis being somewhat closed,
or
modulated, whilst the diaphragm creates the "negative pressure" which
pulses the air through the harp. At the same time, it is the
interaction of
the epiglotis and the base of the tongue that creates the bends, or
partial
bends which embellishes the vibrato and gives it it's classic aural
signature. If in fact it does not involve the epiglotis, but does have
the
characteristic bends, how can you do that with a fixed, relaxed throat
position, and have simply the airstream modulated in intensity through
the
instrument, with the diaphragm?Surely this would pulse volume, but not
create the bends.
OK, I'm ready for the heat.
Reg
Tony Renshaw
Sydney Australia
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