Flute Scales

By Steven Wasser

  

The flute scale determines how well the notes play in tune to each other, octave to octave, and also determines the timbral balance of the notes.  From a mechanical standpoint the flute scale is a function of the following:

• the diameter of the flute tube or “bore”
• the size of each tone hole
• the linear location of each tone hole along the flute tube
• the height of each tone hole

Theobald Boehm developed the basis for today’s flute scales.  Verne Powell initiated an improved scale when he started producing his own flutes with the Powell Scale in 1927.  The next major improvement in scale design was accomplished by Albert Cooper in 1974.  Powell was the first major flute maker to introduce the Cooper Scale, and did so in 1975.  There are several other “modern” scales in use today, including the Bennett Scale used by one Japanese flute maker, and the Deveau Scale used by Haynes. 

Today Powell uses a modified and (we believe!) improved version of the original Cooper Scale which we call the Modern Powell Scale (or just Powell Scale, for short).  When testing instruments for scale we strongly recommend that you consider not only intonation, but timbral balance as well.  A new flute should sound like one instrument, not three separate instruments.

Scale should not be confused with the pitch of an instrument.  Pitch relates to which “A” the instrument has been designed to produce (e.g., A-440, A-442, etc.)  Powell instruments made for the U.S. market are typically pitched at A-442, and play well in tune from A-440 to A-444.

Wooden Flute Tone Holes -- and More

If you've looked closely at the tone holes on a wooden flute, you may have noticed that they look a bit different from tone holes on metal flutes.  At Powell, metal flutes have either drawn or soldered tone holes, but those choices are not possible with a wooden flute body.  After all, with wood, you wouldn't have the option to solder something onto the body or "pull" the hole up from the body.  No, wood is definitely not as flexible as metal.  So, how exactly are the tone holes formed on the wooden flute?  Are there other differences in how the holes are covered by the keys?

The answer is rather simple, actually.  It's all about subtracting material and sculpting the wood.  With a wooden flute, the tone hole is cut out of the body in a process that is referred to as "milling." However, after the tone hole is milled, more material around the hole must be removed to allow clearance for the key cup.  Since it is a wooden body, you are actually carving or sculpting the wood to create the convex shape around the tone hole.  The tone hole itself has a flat edge, so the key mechanism functions exactly the same as it does on a metal flute.  The key cups and pads are exactly the same size and shape as those on a metal flute -- and they cover the hole exactly the same way as they would with a metal flute. 

But what about the rest of the body?  Is it the same thickness as metal?  Obviously, no.  A wooden flute body is thicker than a metal flute body.  The wood has to be thicker so it doesn't crack.  However, the inner bore diameter of a wooden flute is exactly the same as the inner bore of a wooden flute.  So, there are some differences with the wooden flute but many more similarities. 

Wooden flute bodies before and after tone holes are cut.

Close-up on the tone holes (notice carved covex shape around hole for key clearance)

Final assembly with keys in place.