People seem to be stating two possibilities...one is you have a radial 
or elliptical curve and the other is that you have a curve with flat 
spots.   Is it not conceivable that some mouthpieces have a curve 
that  is derived from a non constant radius.  That gives a curve 
without any flat spots. I'm sure this is achieved by feel by many 
refacers. 
 I initially responded to the assymetrical facing question directly so 
it wasn't posted.  I suggested that some people believe reeds vibrate 
alternating one side then the other.  If that is so then the reed is 
not bending as one unit and trying to touch both rails simultaneously. 
It doesn't have to be same on each side.   If you like the idea of 
adhering to radial  curves.  Plug each rail length in separately to 
the spreadsheet.  Allow the left rail to be longer but still maintain 
all the correct numbers for the curve.  It just be that inaccurate 
symmetrical facings and inaccurate  assymmetrical facings are both 
bad.  John

Actually you don't want the reed to vibrate laterally acoss the center axis (side to side) as that is the mode that produces squeaks. It would certainly seem that even rails would be the best way to avoid that possibility. There is a fundamental difference in how sax and clarinet reeds operate due to the bore differences, if I remember correctly. I'll have to try to find that explanation, as it may give a clue as to why flat spots and/or asymmetries on a clarinet facing do not seem to be as vicious as those on a sax mpc.

Toby
  ----- Original Message ----- 
  From: John Price 
  To: MouthpieceWork@yahoogroups.com 
  Sent: Monday, May 02, 2005 11:10 PM
  Subject: [MouthpieceWork] flat sections?


  People seem to be stating two possibilities...one is you have a radial 
  or elliptical curve and the other is that you have a curve with flat 
  spots.   Is it not conceivable that some mouthpieces have a curve 
  that  is derived from a non constant radius.  That gives a curve 
  without any flat spots. I'm sure this is achieved by feel by many 
  refacers. 
  I initially responded to the assymetrical facing question directly so 
  it wasn't posted.  I suggested that some people believe reeds vibrate 
  alternating one side then the other.  If that is so then the reed is 
  not bending as one unit and trying to touch both rails simultaneously. 
  It doesn't have to be same on each side.   If you like the idea of 
  adhering to radial  curves.  Plug each rail length in separately to 
  the spreadsheet.  Allow the left rail to be longer but still maintain 
  all the correct numbers for the curve.  It just be that inaccurate 
  symmetrical facings and inaccurate  assymmetrical facings are both 
  bad.  John





  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 Links

    a.. To visit your group on the web, go to:
    http://groups.yahoo.com/group/MouthpieceWork/
      
    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. 

At one time, clarinet facings were done by simply first making a flat 
table.  Then the rear of the mouthpiece was lifted a certain amount, and 
the mouthpiece sanded to create a flat at a shallow angle to the table 
of the mouthpiece.  Then the sharp corner was rounded off slightly.  I 
think this works only with the narrow tip openings used for clarinet.

But yes, some refacers will put an "easement" in the area of the break, 
so that from the flat table, at the break there is a long radius, which 
then shortens for the remainder of the facing.

This would be done as follows...

A regular curve constant radius curve would be made, for example, a 
tenor sax mouthpiece with .094" tip opening (2.4 mm) with 22 mm facing 
length (44 on E Brand).

Then, only the .0015" and .010" would be brought back to, for example, 
25mm (50) and 20mm (40), with perhaps the .014" feeler brought back 1 or 
1.5 mm.  The rest of the curve on out to the tip would remain the same.

This has the effect of making the low notes smoother and easier without 
hurting the high notes.  This has a nice effect on mouthpieces with 
large tip openings for players who would want to do lush ballads on the 
low end of tenor.  And big band bari players REALLy like this.

This is what Santy Runyon told me he did (and showed me at his studio 
workbench) to Marshall Royal's mouthpiece.

Oops, giving away my secrets!

Paul


John Price wrote:

> People seem to be stating two possibilities...one is you have a radial
> or elliptical curve and the other is that you have a curve with flat
> spots.   Is it not conceivable that some mouthpieces have a curve
> that  is derived from a non constant radius.  That gives a curve
> without any flat spots. I'm sure this is achieved by feel by many
> refacers.
> I initially responded to the assymetrical facing question directly so
> it wasn't posted.  I suggested that some people believe reeds vibrate
> alternating one side then the other.  If that is so then the reed is
> not bending as one unit and trying to touch both rails simultaneously.
> It doesn't have to be same on each side.   If you like the idea of
> adhering to radial  curves.  Plug each rail length in separately to
> the spreadsheet.  Allow the left rail to be longer but still maintain
> all the correct numbers for the curve.  It just be that inaccurate
> symmetrical facings and inaccurate  assymmetrical facings are both
> bad.  John
>
>
>
>
>
> 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 Links
>
>     * To visit your group on the web, go to:
>       http://groups.yahoo.com/group/MouthpieceWork/
>        
>     * To unsubscribe from this group, send an email to:
>       MouthpieceWork-unsubscribe@yahoogroups.com
>       <mailto:MouthpieceWork-unsubscribe@yahoogroups.com?subject=Unsubscribe>
>        
>     * Your use of Yahoo! Groups is subject to the Yahoo! Terms of
>       Service <http://docs.yahoo.com/info/terms/>.
>
>

There's an interesting and very relevant article in a recent (Sept
2004) issue of the "Clarinet" magazine showing a set-up using
high-speed photography (up to 7000 frames per second) to look at the
vibrational modes of clarinet reeds. It says that they NEVER observed
any "lateral vibrations" in reeds - not even in the case of squeaks.
That makes sense because the reed is driven open by a reflected
(standing) wave in the instrument, and it is highly improbable that
there could be any standing wave mode that could drive a reed in
lateral modes. There are amazing sequences pictures of vibrating reeds
in that article. See Clarinet magazine September 2004 page 38-43. This
is extracted from a PhD dissertation which undoubtedly has much more
info than the article does.

- B Smith -

--- In MouthpieceWork@yahoogroups.com, "Toby" <kymarto123@y...> wrote:
> Actually you don't want the reed to vibrate laterally acoss the
center axis (side to side) as that is the mode that produces squeaks.
It would certainly seem that even rails would be the best way to avoid
that possibility. There is a fundamental difference in how sax and
clarinet reeds operate due to the bore differences, if I remember
correctly. I'll have to try to find that explanation, as it may give a
clue as to why flat spots and/or asymmetries on a clarinet facing do
not seem to be as vicious as those on a sax mpc.
> 
> Toby
>   ----- Original Message ----- 
>   From: John Price 
>   To: MouthpieceWork@yahoogroups.com 
>   Sent: Monday, May 02, 2005 11:10 PM
>   Subject: [MouthpieceWork] flat sections?
> 
> 
>   People seem to be stating two possibilities...one is you have a
radial 
>   or elliptical curve and the other is that you have a curve with flat 
>   spots.   Is it not conceivable that some mouthpieces have a curve 
>   that  is derived from a non constant radius.  That gives a curve 
>   without any flat spots. I'm sure this is achieved by feel by many 
>   refacers. 
>   I initially responded to the assymetrical facing question directly so 
>   it wasn't posted.  I suggested that some people believe reeds vibrate 
>   alternating one side then the other.  If that is so then the reed is 
>   not bending as one unit and trying to touch both rails
simultaneously. 
>   It doesn't have to be same on each side.   If you like the idea of 
>   adhering to radial  curves.  Plug each rail length in separately to 
>   the spreadsheet.  Allow the left rail to be longer but still maintain 
>   all the correct numbers for the curve.  It just be that inaccurate 
>   symmetrical facings and inaccurate  assymmetrical facings are both 
>   bad.  John
> 
> 
> 
> 
> 
>   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 Links
> 
>     a.. To visit your group on the web, go to:
>     http://groups.yahoo.com/group/MouthpieceWork/
>       
>     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.

There's an interesting and very relevant article in a recent (Sept
2004) issue of the "Clarinet" magazine showing a set-up using
high-speed photography (up to 7000 frames per second) to look at the
vibrational modes of clarinet reeds. It says that they NEVER observed
any "lateral vibrations" in reeds - not even in the case of squeaks.
That makes sense because the reed is driven open by a reflected
(standing) wave in the instrument, and it is highly improbable that
there could be any standing wave mode that could drive a reed in
lateral modes. There are amazing sequences pictures of vibrating reeds
in that article. See Clarinet magazine September 2004 page 38-43. This
is extracted from a PhD dissertation which undoubtedly has much more
info than the article does.

But...

Backus' book "The Acoustical Foundations of Music" has an illustration on pg. 193 showing a reed tip touching alternately one rail and then the other, with the following text:

"Some clarinet players are under the impression that only the corners of the reed vibrate; the reason for this belief may be demonstrated by taking the wrong end of the mouthpiece in the mouth and sucking on it instead of blowing. When this is done, the reed will be seen to vibrate at its corners. Hoever, the vibration taking place under these conditions, as observed by a stroboscope, is as shown in Fig 5 (b) [as described above] and is a rotation back and forth arounde the center lone of the reed. This vibrations is of a high frequency and is one of the unpleasant squeals to which clarients are prone; it does not take place when the instrument is playing normally.

The rotational vibration just described is not the only source of squeals; there are high frequency modes of vibration in the air column, and the reed can excite these in the same way it can excite the fundamental, vibrating in the normal manner...Furthermore, the reed has a resonance frequency of its own at some 2000 to 3000 cycles per second, depending on how much it is free to vibrate in the players's mouth, and it can vibrate in the normal manner at this frequency. As a result, a whole family of possible squeals exists..."

So it appears that not all squeaks are a result of rotational vibrations, but rotational vibrations always create squeaks.

I have a Beechler metal alto mpc that was unplayable for the squeaks until I evened out the rails--it is most difficult to make it squeak now.

In terms of rails Backus (an accomplished clarinetist in his own right) has this to say:

"In its closed position, the fit of the reeed against the mouthpiece is quite important. Any leakage of air into the instrument during this part of the cycle makes it harder to play, since more air is now flowing into the mouthpiece when its pressure is low rather than when its pressure is high. This is just opposite to the situation necessary to maintain air column vibrations, and means the power is being absorbed from the column instead of supplied to it...If the curvature of the mouthpiece lay is not correct, the reed will not fit properly in its closed position and air can leak in along the sides; this factor is one important cause of differences in mouthpieces..."

Toby

Interesting ... the article I pointed out did not allow the reed to
operate in a "free reed" mode (as happens when sucking on the back of
the mouthpiece), but instead used a device to simulate normal playing
with embouchure contact. Maybe that's why they did not see the
"lateral" vibrations of a high frequency which, as Bacukus notes, do
not take place when the instrument is played normally. They noted in
the article that the embouchure contact greatly influences the
vibrational actions of the reed. - B Smith -


--- In MouthpieceWork@yahoogroups.com, "Toby" <kymarto123@y...> wrote:
> There's an interesting and very relevant article in a recent (Sept
> 2004) issue of the "Clarinet" magazine showing a set-up using
> high-speed photography (up to 7000 frames per second) to look at the
> vibrational modes of clarinet reeds. It says that they NEVER observed
> any "lateral vibrations" in reeds - not even in the case of squeaks.
> That makes sense because the reed is driven open by a reflected
> (standing) wave in the instrument, and it is highly improbable that
> there could be any standing wave mode that could drive a reed in
> lateral modes. There are amazing sequences pictures of vibrating reeds
> in that article. See Clarinet magazine September 2004 page 38-43. This
> is extracted from a PhD dissertation which undoubtedly has much more
> info than the article does.
> 
> But...
> 
> Backus' book "The Acoustical Foundations of Music" has an
illustration on pg. 193 showing a reed tip touching alternately one
rail and then the other, with the following text:
> 
> "Some clarinet players are under the impression that only the
corners of the reed vibrate; the reason for this belief may be
demonstrated by taking the wrong end of the mouthpiece in the mouth
and sucking on it instead of blowing. When this is done, the reed will
be seen to vibrate at its corners. Hoever, the vibration taking place
under these conditions, as observed by a stroboscope, is as shown in
Fig 5 (b) [as described above] and is a rotation back and forth
arounde the center lone of the reed. This vibrations is of a high
frequency and is one of the unpleasant squeals to which clarients are
prone; it does not take place when the instrument is playing normally.
> 
> The rotational vibration just described is not the only source of
squeals; there are high frequency modes of vibration in the air
column, and the reed can excite these in the same way it can excite
the fundamental, vibrating in the normal manner...Furthermore, the
reed has a resonance frequency of its own at some 2000 to 3000 cycles
per second, depending on how much it is free to vibrate in the
players's mouth, and it can vibrate in the normal manner at this
frequency. As a result, a whole family of possible squeals exists..."
> 
> So it appears that not all squeaks are a result of rotational
vibrations, but rotational vibrations always create squeaks.
> 
> I have a Beechler metal alto mpc that was unplayable for the squeaks
until I evened out the rails--it is most difficult to make it squeak now.
> 
> In terms of rails Backus (an accomplished clarinetist in his own
right) has this to say:
> 
> "In its closed position, the fit of the reeed against the mouthpiece
is quite important. Any leakage of air into the instrument during this
part of the cycle makes it harder to play, since more air is now
flowing into the mouthpiece when its pressure is low rather than when
its pressure is high. This is just opposite to the situation necessary
to maintain air column vibrations, and means the power is being
absorbed from the column instead of supplied to it...If the curvature
of the mouthpiece lay is not correct, the reed will not fit properly
in its closed position and air can leak in along the sides; this
factor is one important cause of differences in mouthpieces..."
> 
> Toby

Interesting ... the article I pointed out did not allow the reed to
operate in a "free reed" mode (as happens when sucking on the back of
the mouthpiece), but instead used a device to simulate normal playing
with embouchure contact. Maybe that's why they did not see the
"lateral" vibrations of a high frequency which, as Bacukus notes, do
not take place when the instrument is played normally. They noted in
the article that the embouchure contact greatly influences the
vibrational actions of the reed. - B Smith -


Backus mentions the same thing, saying that lip damping is critical, and suggesting that one simply cannot play a decent note if one uses the teeth instead of the bottom lip.

I think that Backus means that rotational vibrations do not occur when the insturment is sounding normally; he seems to suggest however that they are one of the modes in which squeaks occur when playing. I really can attest to the fact that evening the rails on a couple of mpcs--the alto Beechler and an old metal tenor Berg--made them almost "squeakproof" even when biting high up on the plate with a very open embouchure. Perhaps it is not rotational vibration that is being stopped, but that has been what I assumed was prevented by evening the rails.

Toby