[Cousin Ichbod]

They make noise. How?

If my saxophone has a certain flat pitch and I want to make it better in tune without doing anything to the keys I can:

1. Enlarge the tone hole?
2. Move the tone hole up the body?
3. File the tone hole chimney?

I assume moving the tone hole would be the best option, but what about enlarging it?

This is strictly theoretical. I don't have this problem, I'm just curious what each of the above would do.

 

[kymarto]

Enlarging the hole would not necessarily make the note sharper unless the enlargement also moved the top edge upward. In other words enlarging the hole downward should not generally raise the pitch. Physically moving the tonehole upwards is the best way to raise pitch. Filing the chimney would theoretically raise the pitch, but it would be a minuscule change.

 

[milandro]

the procedure of moving the tonehole to correct a too low intonation is described by a Dutch techinician who undertook this complex and very expensive operation on behalf or Arno Bornkamp in 2007.

Bornkamp came to this shop asking to correct the intonation of the lower notes, the technician moved the C and C# toneholes performing together with a goldsmith the " surgery" . After all the intonation of C# and D were ok but the C couldn't be corrected by moving the B, so he proceeded to place the tone hole protection for the A-B-Bb higher up so that the keys could open more.

I don't know how satisptying all this was because Bornkamp has used this horn only for ONE CD.

The account is all in Dutch here, pictures in the link (cannot copy them)

http://www.saxomania.com/modificatie.html

 

[Cousin Ichbod]

I've read up on how crescents work (on musicmedic.com) so I have a basic understanding of how tone hole placement affects pitch, but why would the tone hole sizes matter? If I move the top of the tone hole up the body 1mm how does that compare to enlarging the diameter 1mm? It would effectively do the same thing right?

That's interesting about Arno Bornkamp' Mk VI. A risky operation to undergo. Looks like it worked, although a bit funny to look at.

 

[BradWit]

Enlarging the tonehole by 1mm would only move the outer edge upward a maximum of .5mm, and move all edges out by the same amount. Moving it up 1mm actually makes the horn 1mm shorter.

 

[kymarto]

Enlarging the tonehole by 1mm would only move the outer edge upward a maximum of .5mm, and move all edges out by the same amount. Moving it up 1mm actually makes the horn 1mm shorter.

Changing tonehole sizes can affect other parameters like venting, and could mean having to change instead of simply move key cups.

 

[Gordon (NZ)]

I've read up on how crescents work (on musicmedic.com) so I have a basic understanding of how tone hole placement affects pitch, but why would the tone hole sizes matter? If I move the top of the tone hole up the body 1mm how does that compare to enlarging the diameter 1mm? It would effectively do the same thing right? t.

When tone holes are small relative to the bore, as for say recorder, then their size is quite relevant, affecting venting (hence pitch) a lot. A smaller hole lowers the pitch, even if the "northernmost" area of the hole's wall stays in the same location. After all, imagine if you reduced a normal size tone hole down to microscopic. It would stop acting as a tone hole at all.

However when tone holes are large relative to the bore, as with fltue or sax, the venting is already excellent, so enalrging the area has little effect.

But yes, if you increased the diameter by 2 mm, while leaving the location the same, that would be much the same as moving the tone hole 1 mm up the instrument. For the increased diameter, the slightly better venting might make the pitch slightly higher still.

 

[tempesax]

I understand that smaller tone holes can lower the pitch.

One example is the pre-Boehm wooden flutes from the 1800s. They did not have any keys, therefore, the fingers needed to close the holes. However, if you put the holes at the best acoustic location, then the fingers could not reach them!!!

The solution: if the note was too sharp (due to the tone hole being too "high" on the flute), make it a bit smaller.

Here is a picture of a "Pratten Perfected keyless wooden flute" that demonstrates this t

 

[adamk]

The C# hole closest to the head on a flute can vary in size, at least from observation.

 

[saxoclese]

To give a perspective: Nederveen's "Acoustical Aspects of Woodwind Instruments" states that to change the pitch of a note 10 cents requires a 1% change in the distance to the (acoustical) top of the instrument, a 10% hole-diameter change, or a 20% hole length change. I assume that the "hole length" on a saxophone or flute would be the height of the toneholes. He also says "we assume 10 cents to be the threshold of perceptibility".

 

[milandro]

Arno Bornkamp' Mk VI. A risky operation to undergo. Looks like it worked, although a bit funny to look at.

He only used it once.... probably for a good reason

 

[Gordon (NZ)]

The C# hole closest to the head on a flute can vary in size, at least from observation.

That's why, for some flutes, mainly older models, the C# is extraordinarily sharp. Grassi comes to mind.
That tone hole has many functions so significant compromises are made, with different parameters for different manufacturers.

 

[soybean]

If you have a choice, it is much better to make sharp notes flatter (using crescents) than to move or enlarge tone-holes to make flat notes sharper.

 

[Gordon (NZ)]

If you have a choice, it is much better to make sharp notes flatter (using crescents) than to move or enlarge tone-holes to make flat notes sharper.

But this tone hole on a flute is a compromise for 8-9 different functions, and probably related to other design issues such as the head taper. The pitch of a particular note is not the only consideration.
These sorts of compromises abound in acoustic design of instruments.