Wednesday, August 29, 2012

Headjoint Show Stoppers

In our last installment of the headjoint series by Steven Wasser, we take a look at the cork assembly and crown.

The headjoint has a cork assembly and a crown at the “dead” end of the headjoint tube.  The purpose of the cork assembly and crown is to prevent the waste of the player’s air stream from going up the headjoint rather than down into the flute tube. 

Some cork assemblies have been developed using o-rings that allow the upper end of the headjoint to vibrate more.  In our experience that vibration actually diffuses acoustical energy.  We draw an analogy to high-end speakers which are often made very heavy in order to produce the purest, most accurate sound possible.  Based on this analogy we want the upper end of the headjoint to be as dead as possible so that the blowing energy creates the strongest possible acoustical wave down the flute tube.

Many headjoint makers have also experimented with the size, shape and material of the end of the cork assembly.  Each shape and material has pros and cons but, on balance, the flat disc made of plated brass or nickel silver seems to work best.

Finally there is - the crown.  This component is decorative as well as functional.  The weight, material and shape of the crown all create subtle acoustical differences.  

Cork assembly
Another view of cork assembly.  Crown screws into the threaded end.
Crowns in silver and gold (10K, 14K and 19.5K).
Underside of crown (where cork assembly attaches).

Wednesday, August 22, 2012

The Boston Wall

Close-up on headjoint wal
Our fourth installment in Steven Wasser's series on headjoints addresses the wall -- or riser, or chimney.  Many names for an integral part of the headjoint.  What are some of the characteristics of this piece?  How is it attached to the headjoint?  Find out below...

The wall of the headjoint is also referred to as the riser or chimney, and is primarily responsible for the shape of the embouchure hole.  The wall is multi-dimensional and extremely difficult to measure.  This difficulty keeps headjoint makers in business.  If the embouchure hole were easy to measure, it could be made entirely by machine. 

To the extent that a wall can be measured there are several critical dimensions:

  • Height which may be different at the front and the back of the wall
  • Side to side diameter
  • Front to back diameter
  • Diagonal
  • Interior angles which again may be different front and back and which are also compounded from multiple angles

The way a wall is attached to the tube and lip plate also affects acoustics as well as durability.  Most headjoint makers silver braze the lip plate to the wall then soft solder the lip/wall assembly to the tube.  A silver brazed joint acts as if the joined pieces were one metal and has a strength of 40,000 psi; a soft soldered joint typically behaves more like a metal glue and normally has a tensile strength of 4,500 psi.  Powell has developed technology that allows the lip/wall assembly to be silver brazed to the tube.
Lip plates and walls

Wednesday, August 15, 2012

All Lip Plates Have Curves

In our third installment of the headjoint series, Steven Wasser discusses the lip plate.  Is it completely a flat surface?  What types of adjustments are made to the lip plate, and how do they affect sound and responsiveness?  Find out more in the post below:

The lip plate would be simple if it were flat, but lip plates usually have compound and multiple curves.  The top looks flat but usually has a dip running north-south (up and down the tube) which provides a more secure or comfortable position for many players and an easier response.  A flat design, on the other hand, might offer more colors.

The lip plate also curves around the flute tube, and one often see a sharp “falloff” at the blowing edge as the lip plate is wrapped tighter around the tube.  In some cases a flat spot is also filed or sanded onto the falloff area. 

Some lip plates have a very sharp edge where the player’s air stream enters the embouchure hole.  Most embouchures also have an overcut which is essentially a bevel on the lip plate edge as it enters the embouchure hole. 

These adjustments to the falloff, blowing edge, and overcut all affect responsiveness, color, and noise.  A sharp blowing edge, for example, can cause noise or a slight hissing sound close up.  On the other hand, the same sharp blowing edge might cause stronger projection and the audience does not hear the blowing “noise.”

Wednesday, August 8, 2012

The Story of the Tube and the Parabolic Taper

In the second installment of our series on headjoints, Steven Wasser explains the taper and position of the embouchure hole.  What type of taper is found in a Powell headjoint?  What exactly is affected by the position of the embouchure hole?  Find out below...

The Story of the Tube and the Parabolic Taper

Your headjoint tube is narrow at the top and wider at the bottom.  The taper affects the flow of air as well as the intonation of the flute. 

A straight taper would be a straight line that runs at an angle.  A parabolic taper is an arc or a curve.  It can be comprised of a continuous arc (i.e., the angle or arc is the same throughout) or a series of arcs.  Although your headjoint might look like it has a straight taper, in fact professional headjoints have a parabolic taper.

It is important to spot the hole on the headjoint tube where the lip and wall assembly is going to be soldered.  The location of the lip/wall assembly on the tube makes a difference.  A number of years ago Andräs Adorján was at Powell Flutes working with our headjoint makers.  He was concerned about the intonation on one note and said, “I think the embouchure hole is too high up the headjoint tube.”  We measured and sure enough, the diameter of the tube where the embouchure hole was being located had somehow shifted from its specified position.  It was now .003” too high up the tube.  We relocated the hole to its proper position and the intonation problem was solved!

Wednesday, August 1, 2012

The Mystery of the Headjoint

14K headjoint and Aurumite headjoint
Welcome to the first in a special five-part series here on FluteBuilder about headjoints.  The headjoint seems simple enough, right?  Well, from the outside it might look that way, but there are several complex components and processes that go into making a professional headjoint.  Steven Wasser, President of Powell Flutes, has written the posts for this series.  He starts with the following post on the principle parts of the headjoint:
I:  The Mystery of the Headjoint

The headjoint is generally acknowledged to be the most acoustically important part of the flute.  It is comprised of 3 primary parts – the tube, the wall or riser, and the lip plate.  Sounds simple, yet headjoint making is shrouded in mystery. 

What starts out as 3 simple parts turns out to be extremely complex.  Let’s start by taking a good look at the embouchure hole where the 3 parts come together.  Can you measure it?  Side to side?  Front to back?  Is the height of the soldered lip plate the same all around?  Do you want it to be?  How about the bottom of the embouchure hole?  Can you measure it?  How?  There are not clean edges for measurements due to all the contours. 

Take a good look inside the embouchure hole.  The top of it is smaller than the bottom part which is inside the tube.  This means the wall runs at an angle.  Are the angles the same all around?  How would you measure where one angle transitions into another?  Are the angles straight or curved?  How would you measure the dimensions of this hole 1 mm down from the surface of the lip plate?  2 mm down?  

Components in early production phase: tube, wall/riser, lip plate
In the next article we’ll examine just the headjoint tube.