Re: [Harp-L] Overblowing with a drinking straw

[Winslow Yerxa <winslowyerxa@xxxxxxxxx>]

The straw experiment (which duplicates something Bobbie Giordano did ten years ago) does not require any radical rethinking of how overblows work. It actually demonstrates both aspects of standard theory:

1) an activator is needed.

2) the correct resonant frequency must be achieved in order to influence the pitch of the reed.

(Air direction, sometimes cited in descriptions of overblow technique, is a coincidental phenomenon in the player's mouth. It's useful as tactile feedback, as are sensations of suction or pressure - they are effects that are useful gauges, but they are not causes.)

The straw does the same thing as the player's tongue at the point where it narrows the air channel, thus speeding up the airflow while reducing air pressure. So it functions as an activator.

The resonant frequency of the chamber attached to the harmonica, whether it be the straw or the player's mouth, will determine whether an overblow is achieved, and what note sounds when you achieve the overblow.

Two things appear to be uncontrolled in Ben's experiment, both of which can be explained by standard theory:

1) Ben does not always get a successful overblow by applying the straw. Could the activation be not properly set up, or might the resonant frequency be outside the ability of the reed to respond? (or maybe he just doesn't have the straw preperly connected to the hole.)

2) Most of he overblows (except, I think, the very first one) are bent up above default overblow pitch by at least a semitone. This indicates that the resonant frequency being set up with the straw (might it be influenced by his mouth shape?) is well above the default pitch of the reed in opening (overblow) mode.

These two facts indicate that the critical shaping of the resonant chamber is a haphazard matter in the straw experiment.

One interesting question it raises, though, is whether the length of the "tunnel" - the narrowed part of the airflow - contributes to the stability, or even the pitch of the overblow.

Winslow Yerxa

Author, Harmonica For Dummies ISBN 978-0-470-33729-5

--- On Mon, 2/2/09, Richard Hammersley <rhhammersley@xxxxxxxxxxxxxx> wrote:
From: Richard Hammersley <rhhammersley@xxxxxxxxxxxxxx>
Subject: Re: [Harp-L] Overblowing with a drinking straw
To: "harp-l Harp L" <harp-l@xxxxxxxxxx>
Date: Monday, February 2, 2009, 3:35 AM

Well, as Ben realises, this challenges some wisdom about how overblows happen.
What we know:
(1) There is a lot of advice out there about the requirements for precise mouth
shape etc to make overblows happen.
(2) It is emphasised in that advice that it is not a matter of blowing hard.
(3) A tube such as a straw increases the speed of air flow and focusses the
flow.

So, are overblows about blowing with just the right speed and focus? Obviously
mouth shape will matter for this, but there might be more than one way to hit
the critical speed. Also, as per the instructions for overblows, that speed will
vary for different pitched reeds.

On 2 Feb 2009, at 09:42, Arnold Wiliem wrote:

> Hi Ben,
> 
> This is fantastic.. I've never seen that a straw could actually switch
> the overblows on. I wonder whether we could practice overblows
> technique by using this method.  Is there any back-pressure you have
> to do when blowing into the straw or just blow with regular breath?
> 
> Arnold
> 
> On Mon, Feb 2, 2009 at 6:39 AM, Ben Hewlett <ben@xxxxxxxxxxxxxxxxxx>
wrote:
>> Hi all,
>> 
>> I recently noticed I can do reasonable overblows by putting a drinking
straw
>> to my harmonica and blowing normally.
>> 
>> There is a demonstration video here
http://uk.youtube.com/user/PaulLennonUK
>> 
>> This may be old news and then again it might be amazing to some
players -
>> take a look!
>> 
>> I've also just posted a video on 'hands-free' playing -
Joe Filisko taught
>> me how to do it, and some of you might enjoy it - I apologise for the
poor
>> taste shown at the end of the video!
>> 
>>>>> 
>>>>> All the best
>>>>> 
>>>>> Ben
>>>>> 
>>>>>> ..........................................
>>>>>> Ben Hewlett CTABRSM
>>>>>> +44 (0)117 908 3838
>>>>>> +44 (0)7973 284 366
>>>>>> ben@xxxxxxxxxxxxxxxxxx
>>>>>> ..........................................
>>>>>> 
>>>>>> www.HarmonicaWorld.net                 Listen to our
CD/Books
>>>>>> www.HarpsCool.co.uk                       School
Teaching (coming soon)
>>>>>> www.youtube.com/PaulLennonUK      Tutorial Videos
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>>>> 
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>> 
>>> 
>>> 
>> 
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Richard Hammersley
Grantshouse, Scottish Borders
http://www.last.fm/music/Richard+Hammersley
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