The Clarinet BBoard

The Clarinet BBoard The C4 standard

New Topic | Go to Top | Go to Topic | Search | Help/Rules | Smileys/Notes | Log In

Newer Topic | Older Topic

Conical pipe

Author: gg590
Date: 2006-03-02 12:26

Good morning,
I'm French, and I leave in the North of France
I'm very interesting by the acoustic of saxophone, and repare then as amateur...
At the present, I'm trying to understand the study of M. BENADE
"Acoustical evolution of wind instrument"
In the page 3 of this document :
We have an first variation of the cylindrical tube for to obtain (the expanding cone).
The expression of fn = fn = (C/4L) Square (2n-1)*2 + (8/p2) (L/Xo)
Can anyone explain this and the calcul of impedance ?
Take you very much for your help !
Sincerely
Gérard

I am French
Born the 02 07 1953
I leave in the North of France at Wormhout 59470
I am interesting by the saxophone acoustic
My postal address :
Gérard COUTTENIER
516, route de Bergues 59470 WORMHOUT

Reply To Message

Re: Conical pipe

Author: lepetitsuisse
Date: 2006-03-02 13:06
Attachment: harmonics.jpg (86k)

Dear Gérard,

The formula you're asking an explanation for, is the expression for the eigen-frequencies (fréquences propres) of a conical tube (see harmonics.jpg I took from the pdf file of Benades study available here: http://ccrma.stanford.edu/marl/Benade/documents/Benade-Physics323-1977.pdf)
This formula gives you the value of any n-numbered eigen-frequencies (just replace "n" by any number). This has nothing to do with an impedance of the cone by the way.
This is fairly complicated physics and as I don't know your background I won't go to much into details here. If ever you'd like a more detailed explanation, just let me know.

Lepetitsuisse

Post Edited (2006-03-02 13:15)

Reply To Message

Re: Conical pipe

Author: Chris P
Date: 2006-03-02 14:21

Just an uneducated guess as I haven't a clue about the physics involved, but seeing the diagram with the superimopsed cylinder on the cone shows the cylinder and (truncated) cone both hold the same volume.

And could this be the reason why they both overblow an octave - if the cylinder is open ended and the cone is closed at one end?

Reply To Message

Re: Conical pipe

Author: gg590
Date: 2006-03-02 14:40

Thank you very well for your response Dear Lepetitsuisse.
I give to you more informations of me.
I have 53 years and I have an diplome d'university an electricity (BAC +2years).
I have some old and relatively recent instruments (buffet crampon, couesnon,gautrot, selmer markVI, MarkVII...), and I play a little on an sax tenor Selmer Super action II.
I try to make an little memory for me on the evolution technic of the saxophone (between 1860 and 1960).
So, I try to know how M. BENADE has found this formule ?It's write next :
"Approx but good See Morse E..24.23 page 286 " ?
How try these information ?
Or
Can you explain me more
Is it possible for you ?
Sorry, I am not very good in English...
I have need many dictionnary, but I try to improve...
Sincerely
Gérard

I am French
Born the 02 07 1953
I leave in the North of France at Wormhout 59470
I am interesting by the saxophone acoustic
My postal address :
Gérard COUTTENIER
516, route de Bergues 59470 WORMHOUT

Reply To Message

Re: Conical pipe

Author: Bob Phillips
Date: 2006-03-02 14:55

Thank you for the Stanford University reference.

Bob Phillips

Reply To Message

Re: Conical pipe

Author: lepetitsuisse
Date: 2006-03-02 16:14

Gérard,

Besides other languages I also speak french. If you'd like more detailed information, just write me a mail offline. I'll be happy to help you.

Lepetitsuisse

PS: There's a fairly good website about instrument acoustics from the university of New South Wales in Australia. Check the 'Open vs Closed pipes' section:
http://www.phys.unsw.edu.au/music/

Post Edited (2006-03-02 16:29)

Reply To Message

Avail. Forums | Threaded View

Newer Topic | Older Topic

The Clarinet Pages

For Sale
Put your ads for items you'd like to sell here. Free! Please, no more than two at a time - ads removed after two weeks.