Re: [Harp-L] Chromatic and Diatonic harp volume....

[Vern <jevern@xxxxxxx>]

On Feb 26, 2012, at 12:59 PM, Joseph Leone wrote:

> 
> On Feb 26, 2012, at 3:02 PM, Vern wrote:
> 
>> Because a slide must have some clearance to work, the chromatic has a source of leakage not present in the diatonic.  As the precision of the slide increases, for instance in the Renaissance or Saxony, the loudness of the chromatic approaches that of the diatonic.
> 
> AND, with a diatonic, you are standing closer to the reeds. 

I don't think that this makes a lot of difference.  The distance to the reeds is very long in the Renaissance.
>> 
>> You can greatly improve the loudness and responsiveness of a 270 by shaving/filing the U-channel of the slide to reduce the clearance to about .002" This is a tricky procedure but several harmonica techs can do it for you.  It is described in Tate's and Schackner's books.   As they come from the factory, slide clearances in the 270 vary from about .004" to .007."  IMO, this is the only effective modification for improving the performance of the 270.
> 
> I guess this is because the factory assumes that people won't keep the slides as free as they should. Closing up the clearance requires a spiffy clean (and flat) slide.

You assume that Hohner can and does control the slide clearance precisely.  Unless they add the manufacturing step of machining the U-channel flanges AFTER they are bent up, they can't accurately control the clearance.  They have to allow more clearance than necessary to accommodate their sloppy manufacturing tolerance.  That is my analysis...I could be wrong.  

>> I believe that it is not the leakage of breath that affects loudness. I think that the leakage dampens the resonance of the player's embouchure.  In very simple terms it is not so much the loss of air as it is the loss of the sound.
> 
> Yes, it's like the difference between turning on a faucet only part way with 22 lb of pressure in the line and turning it on all the way with 14.7 lb of pressure. The leakage drops the pressure...hence less force. Less water force (less air to the reed) and you don't get the dishes as clean (sound as loud).

I don't think that it is less air to the reed. It is more like the change in sound in a trumpet wen you open the spit valve.  The leak dampens the resonance of your embouchure. Otherwise, I don't think that you would notice any difference in the amount of breath required.

Vern