Chamber size and "nodes" (Mouthpiece Work Yahoo Group)

FROM: zrspilot (zrspilot)

SUBJECT: Chamber size and "nodes"

Merry Christmas to everyone on this most interesting group. I've got a question about 
the size of a mouthpiece chamber and how it might affect the intonation "nodes."

Most agree that older saxes (in my case the baritone) seem to play better with 
mouthpieces that have large chambers.

There's also been the suggestion that intonation of specific notes in a horn can be 
adjusted by making minute (but dangerous) adjustments to the "node" points in the 
the neck.

My question: Does the chamber size affect the acoustic length of the body tube? And 
if so...does that mean the "nodes' physically fall at different spots for different 
chamber sizes?

Thanks,
Matso Limtiaco
Everett WA

FROM: sjrosner (sjrosner)

SUBJECT: Re: Chamber size and "nodes"

agreed on merixmas...just putting the finishing touches on our holiday
meal...

On the point of intonation/tone/neck/mouthpieces, I've been thinking
and would like the 'gut' reaction of the tech-geeks in the crowd:
It seems to me that the closer to your lungs it gets, the more
important it is. Upper stack leaks are more important than lower
stack, necks(curve and taper) are even more so, mouthpiece chambers,
then tip opening, then mouth/throat/lungs, this is increasing order of
importance in tone formation (IMHO). ??comments??

--- In MouthpieceWork@yahoogroups.com, "zrspilot" <zrspilot@y...> wrote:
> 
> Merry Christmas to everyone on this most interesting group. I've got
a question about 
> the size of a mouthpiece chamber and how it might affect the
intonation "nodes."
> 
> Most agree that older saxes (in my case the baritone) seem to play
better with 
> mouthpieces that have large chambers.
> 
> There's also been the suggestion that intonation of specific notes
in a horn can be 
> adjusted by making minute (but dangerous) adjustments to the "node"
points in the 
> the neck.
> 
> My question: Does the chamber size affect the acoustic length of the
body tube? And 
> if so...does that mean the "nodes' physically fall at different
spots for different 
> chamber sizes?
> 
> Thanks,
> Matso Limtiaco
> Everett WA

FROM: kwbradbury (Keith Bradbury)

SUBJECT: Re: Chamber size and "nodes"

Ferron's book has an illustration of the nodes along an alto and 
tenor neck.  But it does not go into a mouthpiece.  I suppose you 
could extrapolate the sequence but extrapolations often are wrong 
compared to the real theory.  I would guess they would be off as soon 
as the mouthpiece chamber is no longer a similar geometry to the 
taper of the neck.

Ferron suggests an emperical method where one actually drills holes 
in a (hopefully test) sax neck to find the nodes or anti-nodes (I'm 
not sure which it was without cracking open the book).  Using a test 
mouthpiece I suppose you could do the same thing.  I do not know if 
this knowledge would be real useful.  We basically get along OK 
without it.  But it could provide some enlightenment.

FROM: kymarto (Toby)

SUBJECT: Re: Chamber size and "nodes"

It's not exactly that the chamber size changes the length of the tube, but for the partials to "line up" correctly the volume of the mpc should be the same as the volume of the truncated end of the cone that forms the bore. IOW the only mathematically correct bore is a cone that goes out the very end. Since that is impossible for playing music--you need somewhere to put the mpc--the end of the cone is cut off. That is the end of the neck. The volume of the mpc should be the same as the volume of the end piece that was cut off. If it is not it throws the partials out of a true integer relationship with the fundamental. Thus the first octave notes are OK since they are all the fundamentals of the tube length, but once you get into the second octave which is primarily the second partial problems begin. 

To answer your question the nodes of the partials shift in relation to the nodes of the fundamental if the chamber is not the right size, but don't forget that there are a zillion other things that also do this including bore geometry, the extra compliance added by tone holes, the different impedance of smaller side holes versus big end hole, the different air temperature in the top of the horn vs. the bottom, the extra CO2 at the top of the tube (from the player's breath) and moisture as compared to lower down, etc.

Toby
  ----- Original Message ----- 
  From: zrspilot 
  To: MouthpieceWork@yahoogroups.com 
  Sent: Sunday, December 26, 2004 9:09 AM
  Subject: [MouthpieceWork] Chamber size and "nodes"

  Merry Christmas to everyone on this most interesting group. I've got a question about 
  the size of a mouthpiece chamber and how it might affect the intonation "nodes."

  Most agree that older saxes (in my case the baritone) seem to play better with 
  mouthpieces that have large chambers.

  There's also been the suggestion that intonation of specific notes in a horn can be 
  adjusted by making minute (but dangerous) adjustments to the "node" points in the 
  the neck.

  My question: Does the chamber size affect the acoustic length of the body tube? And 
  if so...does that mean the "nodes' physically fall at different spots for different 
  chamber sizes?

  Thanks,
  Matso Limtiaco
  Everett WA

  Got a Mouthpiece Work question?  Send it to MouthpieceWork@yahoogroups.com

  Visit the site at http://groups.yahoo.com/group/MouthpieceWork to see the Files, Photos and Bookmarks relating to Mouthpiece Work.

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              ADVERTISEMENT

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FROM: kymarto (Toby)

SUBJECT: Re: Chamber size and "nodes"

I would say that the closer to the top of the tube the more globally it affects the sound, since for the most part downstream doesn't affect upstream, but upstream always affects downstream.

Toby

  ----- Original Message ----- 
  From: sjrosner 
  To: MouthpieceWork@yahoogroups.com 
  Sent: Sunday, December 26, 2004 10:37 AM
  Subject: [MouthpieceWork] Re: Chamber size and "nodes"

  agreed on merixmas...just putting the finishing touches on our holiday
  meal...

  On the point of intonation/tone/neck/mouthpieces, I've been thinking
  and would like the 'gut' reaction of the tech-geeks in the crowd:
  It seems to me that the closer to your lungs it gets, the more
  important it is. Upper stack leaks are more important than lower
  stack, necks(curve and taper) are even more so, mouthpiece chambers,
  then tip opening, then mouth/throat/lungs, this is increasing order of
  importance in tone formation (IMHO). ??comments??

  --- In MouthpieceWork@yahoogroups.com, "zrspilot" <zrspilot@y...> wrote:
  > 
  > Merry Christmas to everyone on this most interesting group. I've got
  a question about 
  > the size of a mouthpiece chamber and how it might affect the
  intonation "nodes."
  > 
  > Most agree that older saxes (in my case the baritone) seem to play
  better with 
  > mouthpieces that have large chambers.
  > 
  > There's also been the suggestion that intonation of specific notes
  in a horn can be 
  > adjusted by making minute (but dangerous) adjustments to the "node"
  points in the 
  > the neck.
  > 
  > My question: Does the chamber size affect the acoustic length of the
  body tube? And 
  > if so...does that mean the "nodes' physically fall at different
  spots for different 
  > chamber sizes?
  > 
  > Thanks,
  > Matso Limtiaco
  > Everett WA

  Got a Mouthpiece Work question?  Send it to MouthpieceWork@yahoogroups.com

  Visit the site at http://groups.yahoo.com/group/MouthpieceWork to see the Files, Photos and Bookmarks relating to Mouthpiece Work.

  To see and modify your groups, go to http://groups.yahoo.com/mygroups 

        Yahoo! Groups Sponsor 
              ADVERTISEMENT

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    a.. To visit your group on the web, go to:
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    b.. To unsubscribe from this group, send an email to:
    MouthpieceWork-unsubscribe@yahoogroups.com

    c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

FROM: kymarto (Toby)

SUBJECT: Re: Chamber size and "nodes"

I would doubt whether the mpc contains "nodes" as such. Basically the tip is a pressure node, but the next significant pressure node would probably already be in the neck, even for the high notes.

Toby

----- Original Message -----
From: Keith Bradbury
To: MouthpieceWork@yahoogroups.com
Sent: Sunday, December 26, 2004 11:51 AM
Subject: [MouthpieceWork] Re: Chamber size and "nodes"

Ferron's book has an illustration of the nodes along an alto and
tenor neck. But it does not go into a mouthpiece. I suppose you
could extrapolate the sequence but extrapolations often are wrong
compared to the real theory. I would guess they would be off as soon
as the mouthpiece chamber is no longer a similar geometry to the
taper of the neck.

Ferron suggests an emperical method where one actually drills holes
in a (hopefully test) sax neck to find the nodes or anti-nodes (I'm
not sure which it was without cracking open the book). Using a test
mouthpiece I suppose you could do the same thing. I do not know if
this knowledge would be real useful. We basically get along OK
without it. But it could provide some enlightenment.

Got a Mouthpiece Work question? Send it to MouthpieceWork@yahoogroups.com

Visit the site at http://groups.yahoo.com/group/MouthpieceWork to see the Files, Photos and Bookmarks relating to Mouthpiece Work.

To see and modify your groups, go to http://groups.yahoo.com/mygroups

Yahoo! Groups Sponsor
ADVERTISEMENT

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a.. To visit your group on the web, go to:
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MouthpieceWork-unsubscribe@yahoogroups.com

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FROM: zrspilot (zrspilot)

SUBJECT: Re: Chamber size and "nodes"

Reason I'm asking: My '67 Martin Committee baritone is a great horn...except for the 
middle E and F, which are painfully sharp - around 20+ cents - when the rest of the 
horn plays within +/- 10 cents with its current pads, key heights, etc.

My theory is that there's a ding or two in the neck in just the wrong places, and that is 
what's causing just those two notes to be so sharp. The neck & crook are generally in 
very good shape overall, and there's nothing that looks like major damage from its 
previous life, but I (and the three techs who've looked at this horn) can't figure out 
why those notes and only those notes are so sharp.

So my thought is that if the chamber affects where those nodes occur, then a larger 
chamber might acoustically move the nodes to a different physical location, and 
possibly change the intonation of those notes for the better.

But these explanations so far suggest that this won't happen, correct? The larger 
chamber would "flatten" the entire horn, which would then cause everything except 
the middle E and F to be flat, all other things (like placement on the cork) being 
equal. Right? Or am I so acoustically clueless that this is also incorrect? Perhaps I 
should just stick to arranging!

Thanks,
Matso Limtiaco
Everett WA

--- In MouthpieceWork@yahoogroups.com, "Toby" <kymarto123@y...> wrote:
> I would doubt whether the mpc contains "nodes" as such. Basically the tip is a 
pressure node, but the next significant pressure node would probably already be in 
the neck, even for the high notes.

FROM: kwbradbury (Keith Bradbury)

SUBJECT: Martin Bari

Is E1 and F1 +10, -10 or in tune?


		
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FROM: zrspilot (zrspilot)

SUBJECT: Re: Martin Bari

E1 and F1 are usually within the range 0 to -10, when C2 = 0 and the horn is at room 
temp (70 or so).

OT: I've tried tonehole crescents. They work fabulously for the middle E and F but 
detune E1 and F1 way too much. Might be a case of splitting the difference, I guess.

--- In MouthpieceWork@yahoogroups.com, Keith Bradbury <kwbradbury@y...> 
wrote:
> Is E1 and F1 +10, -10 or in tune?

FROM: kymarto (Toby)

SUBJECT: Re: Martin Bari

I seriously doubt that neck dings would have anything to do with your problem. Think about it: the partials that are detuned are the first partials of E1 and F1; any nodes that affect those would be way below the neck, and anyway local dings almost never detune notes--you need to involve a fairly large area of the bore to do that.

I have a different theory: I would guess that the D is also sharp, but the octave vent placement masks that: I'll bet the whole bottom end of the middle register is basically sharp. That could definitely be a mpc issue: have you tried other mpcs and how did that affect the problem?

As far as tonehole crescents go: I was told by a very good repairman that if you reduce the diameter of the toneholes equally (a full ring) that that flattens both octaves equally, but if you put a shim only on the top part of the tonehole it will flatten the upper register more than the lower register. I would suggest trying to shim just the upper parts of the offending toneholes. I use strips of rubber I cut off sheets, and glue them in with contact cement. You don't have to worry about edges or the fact that the toneholes are no longer round with holes of that size, and you can try different thicknesses and lengths of stripping to see if you can get in the ballpark for both octaves.

Toby
----- Original Message -----
From: zrspilot
To: MouthpieceWork@yahoogroups.com
Sent: Sunday, December 26, 2004 2:23 PM
Subject: [MouthpieceWork] Re: Martin Bari

E1 and F1 are usually within the range 0 to -10, when C2 = 0 and the horn is at room
temp (70 or so).

OT: I've tried tonehole crescents. They work fabulously for the middle E and F but
detune E1 and F1 way too much. Might be a case of splitting the difference, I guess.

--- In MouthpieceWork@yahoogroups.com, Keith Bradbury <kwbradbury@y...>
wrote:
> Is E1 and F1 +10, -10 or in tune?

Got a Mouthpiece Work question? Send it to MouthpieceWork@yahoogroups.com

Visit the site at http://groups.yahoo.com/group/MouthpieceWork to see the Files, Photos and Bookmarks relating to Mouthpiece Work.

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