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the physics of how saxes work

woolyhead

New Member
Messages
19
The pitch of a note from an organ pipe doubles when the end is changed from open to a closed note. Although a sax isn't a parallel cylinder but a conical tube (mainly) I would expect that what determines the pitch of any given note is a combination of tube length plus end effects. Does anyone disagree? Do they know anything about the effect and relationship of the cone angle and tube length to harmonic resonances?
 

kevgermany

ex Landrover Nut
Subscriber
Messages
21,947
You'll get most of what you're looking for from Nick's link.

What you'll probably miss is that the cone is trunicated at the neck end. And the volume of the mouthpiece has to match the volume of the truncated portion of the cone. As the angle is quite small this truncated length is more than you'd think. Calculate the length volume of the truncated portion by taking a few measurements to establish the taper, then work from the id of the body tube/neck, but be careful - there are parallel section in the sax and neck. Lots of other things to take into account as well, like tone holes, whether the adjacent tone hole is open or closed.

Take a look at this if you want more detail:

http://www.amazon.co.uk/Acoustical-...5779/ref=sr_1_7?ie=UTF8&qid=1317064850&sr=8-7
 

Taz

Busking Oracle
Messages
3,661
I stick the pointy end in me gob, wiggle me fingers and blow! Noise changes as per wiggle of the fingers......Simples!
 

BigMartin

Well-Known Member
Messages
3,904
The conical bore (as distinct from cylindrical as in clarinet/flute/organ) makes all the difference. Doesn't matter too much what the cone angle is. You're basically getting shperically symmetric solutions to the wave equation.
 
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old git

Tremendous Bore
Messages
5,545
Very simple question from an extremely simple bloke.

Are all organ pipes cylindrical?

If so, why aren't the outside of the pipes cylindrical?
 

old git

Tremendous Bore
Messages
5,545
As some pipes, sorry, can't forget about those magnificent pipe organs, are blown onto a fipple, just like a flute or whistle, you could theoretically overblow an octave and possibly some other harmonics.

Maybe that's why they fit pressure regulators to them.
 

BigMartin

Well-Known Member
Messages
3,904
Whatever it was, let's hope he managed it.
Before your imaginations run riot, I just wanted to delete a post which

a) didn't really make sense in the context of what had been said

and

b) I was worried that the tone might have come accross as a bit crabby.

To paraphrase OG (well, there wasn't a TM symbol on it), apologies for being dull.

Cheers

Martin
 

kevgermany

ex Landrover Nut
Subscriber
Messages
21,947
Agreed - lots of variation - some wooden flue type pipes for example (as in Durham cathedral) have square cross-section
I find it really interesting that for woodwinds the generally accepted theory is that the material the instrument's made of doesn't affect the sound, but organ builders have, for many centuries, picked different materials for their pipes to get different sounds. And when the EU decided to ban the use of lead a few years back, one of the loudest objections came from the organ makers...
 

kevgermany

ex Landrover Nut
Subscriber
Messages
21,947
Before your imaginations run riot, I just wanted to delete a post which

a) didn't really make sense in the context of what had been said

and

b) I was worried that the tone might have come accross as a bit crabby.

To paraphrase OG (well, there wasn't a TM symbol on it), apologies for being dull.

Cheers

Martin
That's his story, and I'm sticking to it.;}
 

Tenor Viol

Full of frets in North Shropshire
Subscriber
Messages
5,946
I find it really interesting that for woodwinds the generally accepted theory is that the material the instrument's made of doesn't affect the sound, but organ builders have, for many centuries, picked different materials for their pipes to get different sounds. And when the EU decided to ban the use of lead a few years back, one of the loudest objections came from the organ makers...
A nearby village with a fine Medieval church has a good organ. Went to a recital recently and the organist made a comment about one of the flute stops being particularly fine and that this was due to them being C19th and made of a particular alloy which is either rare or not used now
 

old git

Tremendous Bore
Messages
5,545
I find it really interesting that for woodwinds the generally accepted theory is that the material the instrument's made of doesn't affect the sound, but organ builders have, for many centuries, picked different materials for their pipes to get different sounds. And when the EU decided to ban the use of lead a few years back, one of the loudest objections came from the organ makers...
Would that be because of the workability of lead and the alloy in tenorviol's case?
 

Jeanette

Organizress
Cafe Moderator
Messages
25,910
Before your imaginations run riot, I just wanted to delete a post which

a) didn't really make sense in the context of what had been said

and

b) I was worried that the tone might have come accross as a bit crabby.

To paraphrase OG (well, there wasn't a TM symbol on it), apologies for being dull.

Cheers

Martin
So many scenarios running through my mind;}

I am sure we would never think you were being crabby:blowkiss:

Jx

PS If you are not logged in some of these post will have lost their meaning
 

Lodger

Member
Messages
108
I have led a sheltered life, so until I read this thread I had assumed that OG's title was describing a character trait.
 

kevgermany

ex Landrover Nut
Subscriber
Messages
21,947
Just thinking about the cone angle some more, I read somewhere, can't remember where, that an excessive angle leads to instability of some notes.

As far as I know, the so call 'large bore' saxes had a slightly larger cone angle. I've seen something about cone angle and resonances and the tuning of the individual registers, but can't remember what or where. Sorry.
 
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