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Please excuse me as I'm a mechanical engineer who has forgotten most of 
his EE schooling - but wouldn't there be some way to measure the 
current flowing through the speaker to identify resonant "peaks" when 
sweeping through gradually with the frequency?  Those peaks perhaps 
identifying the frequency at which the horn is actually tuning at?  I 
would expect the amperage to drop when the frequency coming through the 
speaker matched with the air column's natural frequency (similar to how 
you can blow out a stereo speaker more easily if you hit upon just the 
right resonant frequency).  Obviously, there would be multiple 
localized peaks to choose from when doing the sweep, but the 
fundamental would stand out beyond the harmonics.  These current 
fluctuations would be very subtle and difficult to measure.  The 
testing equipment would have to be pretty high-grade.

Think of adjusting the bass port on a speaker enclosure.  The saxophone 
in the experiment would be a very large port to a very small speaker.

Ok - I'm thinking about this too much...

--- In MouthpieceWork@yahoogroups.com, "Bob Phillips" 
<rwphillipsidaho@...> wrote:
>
> I think that kymarto123 has the right idea.  The tone generator is not
> strongly (enough) coupled to the air column --so it doesn't "play" 
the horn.
> 
> bob phillips
>

Ed, you are on the right track, and I think something like that was done.
   
  I will begin with this... ever turned on your PA system and gotten feedback?  It did that with no signal input, didn't it.  It produced a high pitched squeel even with nobody singing, instruments playing, nothing.  Just feedback.  And you adjusted volume, or tone controls, or mic position and stopped the feedback.  The system (PA, mic, room, speakers) was in resonance. 
   
  In speaker design/tuning, for example, an 8 ohm woofer, a 50 ohm resistor is placed in series, with the woofer, and a voltmeter is put across the terminals of the woofer.
   
  Frequency from the amp is adjusted until the voltmeter reads its highest reading.  That is where the impedance of the woofer is maximum... meaning it is resonating at that frequency.
   
  If the woofer is connected directly to the amplifier, by necessity, the voltage across the terminals is the same as the voltage coming from the amp, it can't be anything else.  At resonant frequency, since the impedance increases, the current drops as you said.
   
  But when that series resistance is placed in series, the woofer reacts the same way, and obeying Ohm's law, since the impedance inceases, the voltage does, too, in relation to the series resistor.
   
  OK, so with the series resistance, we can make a voltage peak at resonance.  And the sax wants to resonate a certain pitches.  You can make notes on the sax without even blowing, just by plunking down the keys quickly, but there is no energy input to sustain those notes, so they quikly die away. 
   
  With the series resistance, the cone of the woofer is not controlled so completely by the amplifier as it would be normally.  We have greatly interfered with "damping factor".  So, if we were to take that signal from the speaker terminals, feed that back to the input of the amp we could make it "feedback"... just as the returning wave from blowing comes back up the bore of the sax and blows the reed open, allowing another puff of air, beginning another cycle.  If resistances and feedback were controlled, we could do this electically.  And the system would resonate with the sax.
   
  I'll come up with a circuit for this.  I know generally how to do it, I just don't have all the particulars figured out.
   
  But the point was this.  This was not "Santy's experiment".  It was a demonstration shown to him.  I knew Santy for a number of years, and he was not one to just make up things.  He told me himself he did not understand the science behind the demonstration, and it was a very long time ago.
   
  (An aside, a few weeks before Santy went back into the hospital and passed away, I was in his studio.  There on his workbench was a thick manual from a plastics manufacturer, technical info on plastics and rubbers, and Santy had been studying that.  He was a very highly self educated person.  He did not "make things up".  He didn't need to.)
   
  (Another aside... Benade used, as clearly described in his papers, some experimental speaker drivers to excite tones in cylindrical bores, simulating the clarinet.  Conn also used speaker drivers to excite tones in trumpet bells so that measurements could be made, as no human could blow the trumpet the same way twice.)
   
  But there were two points from this demonstration.  
   
  (1)  The air blowing THROUGH the sax bore does not create the tone.  The saxophone's (or clarinet's, or any other wind instrument) tone is the result of a standing wave within the instrument.  (There goes all the theory about "aerodynamics" and such within the mouthpiece and instrument.)  The air going through the instrument is simply the escape path available during engergizing the "motor" (reed/breath) that generates the standing wave.  You could, for example, remove the reed, or just blow into the end of the neckpipe until you turn blue and never produce a tone.  It is the standing wave that produces the tone.
   
  (2)  The conditions needed (amount of bite, embouchure pressure, etc) necessary to make an alto mouthpiece resonate at A=880 hz (or G for tenor, etc) are the same conditions needed to play both the upper and lower registers without embouchure change.
   
  OK, I'm going back to speaker analogy here.  There are a number of measurements, parameters, in measuring woofers, known as Theile-Small Parameters, named for the mathematicians that first described them, that can be used in formulae to predict the performance of a speaker SYSTEM (woofer + box + port, if used).  
   
  In a 1978 paper presented to AES, Pat Snyder of Speakerlab pointed out that in producing woofers they would all vary somewhat in the parameters, but the parameters varied together in a certain way, and gave the formulae for their relationship.  He pointed out that the main design features, size and strength of magnet, voice coil dimensions, cone mass, etc, could be held to good production tolerances, but there were still variances in parameters.  But when the relationship of these parameters were looked at as a whole, it was pretty constant.
   
  So for a given production lot, even though Vas, Fs, etc, varied, when the real woofers were put in the same box with the same port, those differences cancelled out and measurements of the speaker SYSTEMS were very much the same.
   
  I think that is what happens here with the mouthpiece, reed, and embouchure.  Even though the reed strength, facing length, tip opening, embouchure tension (one thing the player can change easily) all differ, the total conditions that would allow the alto sax mouthpiece to blow A=880 hz is correct for playing the whole instrument.  The differences cancel out, and the things that really matter resonate with the sax correctly.
   
  So, I don't think the guy that demonstrated the instrument put in a signal of 880 hz.  I think he created conditions that allowed the mouthpiece/speaker alone to RESONATE at 880 hz.  And those same conditions that allowed the mouthpiece to resonate there, when placed on the body of the sax, would allow resonation for any key combination, both the upper and lower register.
   
  He observed that if he set up resonation much below 880 hz of the mouthpiece alone, then when placed on the sax, it would resonate for the low register, but not the upper register.
   
  If he set up resonation much above 880 hz of the mouthpiece alone, then when placed on the sax, it would resonate for the upper register, but not the low register.  
   
  Only when it was set up to resonate the mouthpiece at around 880 hz would it then work for both the upper and lower registers.
   
  With just attaching a tuner (oscillator-amplifier) to the speaker to the sax, all the resonance is going on within the oscillator inside of the tuner.  The rest of the system is not involved.  There is no feedback mechanism going back to the beginning to adjust the pitch.  With a woodwind, the feedback mechanism is the returning wavefront coming back up the bore.
   
  So I think the mistake we make is in thinking there was an INPUT of 880 hz to force the system to play 880 hz.  No, the system was adjusted to allow resonation at that point.
   
  So, I need to set up a system that when adjusted to resonate, will resonate on its own without signal input.  Then by changing the key combinations, the resonance of the system with change with it.
   
  BTW, Benade observed that the natural resonance of the REED ONLY, must be higher than a musical pitch it is asked to produce.  And he gave the math for that.
   
  Paul
   
   
   
  

Ed <edzentera@...> wrote:
          Please excuse me as I'm a mechanical engineer who has forgotten most of 
his EE schooling - but wouldn't there be some way to measure the 
current flowing through the speaker to identify resonant "peaks" when 
sweeping through gradually with the frequency? Those peaks perhaps 
identifying the frequency at which the horn is actually tuning at? I 
would expect the amperage to drop when the frequency coming through the 
speaker matched with the air column's natural frequency (similar to how 
you can blow out a stereo speaker more easily if you hit upon just the 
right resonant frequency). Obviously, there would be multiple 
localized peaks to choose from when doing the sweep, but the 
fundamental would stand out beyond the harmonics. These current 
fluctuations would be very subtle and difficult to measure. The 
testing equipment would have to be pretty high-grade.

Think of adjusting the bass port on a speaker enclosure. The saxophone 
in the experiment would be a very large port to a very small speaker.

Ok - I'm thinking about this too much...

--- In MouthpieceWork@yahoogroups.com, "Bob Phillips" 
<rwphillipsidaho@...> wrote:
>
> I think that kymarto123 has the right idea. The tone generator is not
> strongly (enough) coupled to the air column --so it doesn't "play" 
the horn.
> 
> bob phillips
>



                           


Link to Paul's articles from Main page of "Saxgourmet":
		http://www.saxgourmet.com
Listen to Paul's MP3's and view saxophone photos at:
           http://briefcase.yahoo.com/tenorman1952

Paul Coats is the sole US importer of SAXRAX products from 
http://www.saxrax.com 
For SAXRAX products, email Paul at saxraxus@...
       
---------------------------------
Be a better friend, newshound, and know-it-all with Yahoo! Mobile.  Try it now.

I need to correct myself.  When a resonant frequency is "found", the 
amperage would increase - not decrease.  The impedance drops.

Paul wrote:
"So I think the mistake we make is in thinking there was an INPUT of 
880 hz to force the system to play 880 hz.  No, the system was adjusted 
to allow resonation at that point."

I think I can see what's happening.  What the reed is doing related to 
the tone produced is always going to be effected by the length of the 
air column.  With a reed vibrating at X, a long shank mp will produce a 
different tone than a short shank mp.  If you measure the tone with the 
neck on, mp placement will again make a difference as to the tone 
produced even if the reed vibration rate is the same.  Put the long 
shank mp on a little further, and you get the same tone out of the neck 
as with the short shank.  

So "putting a tone" into the mp isn't really what is being done, it's 
putting a frequency in that subsequently produces a tone depending on 
the tube length.  In the Runyon experiment, a speaker that could drive 
a lot of air may have been able to produce a tone, even a tone of A880, 
but the frequency of the speaker was likely a random and much higher 
frequency.

I don't see that there could be a single magical reed frequency at the 
mp.  In fact, when playing my contrabass clarinet, it's really obvious 
that the jaw rattling low tones are because the reed is vibrating so 
slow.  It's lowest note is 29.14hz.  For those interested, check out 
http://www.contrabass.com/pages/frequency.html

My pitch pipe has a separate reed for each note.  Each reed plays the 
same note whether in or out of the pipe (no air column length) and each 
plays only one note.  When connected to the "air column" of my alto 
sax, the reeds didn't seem to react to changes in column length.  

I just put got a 4' length of 1/2" copper pipe from the garage, put 
a "neck cork" on it, and put on a tenor mp.  I blew a fairly accurate 
low C just by coincidence.  But only a C and it was very hard to try to 
change the tone.  Using the pitch pipe C reed produced a C that sounded 
like it was coming through a 4' pipe.  A produced an A, B a B, etc.  

Simply put, the metal reed on the pitch pipe didn't respond to air 
column feed back.  The length of the column seemed to really control 
the cane reed's vibration rate, but not the metal reed.  Some of this 
may have been air leakage.  The tenor mp squeaked high until it was 
totally sealed.  It's a little more difficult to get the pitch pipe to 
seal, but I didn't get the feeling that it would matter.

I'm not sure what to make of this, other than it's a lot more 
complicated than I initially thought.

Mark

No one said the reed was vibrating at 880 hz when the mouthpiece is placed on the alto saxophone, and some other pitch is being played.
   
  And you are correc, when you blow the low note on your contrabass clarinet, the reed is vibrating at that frequency.
   
  But if you removed the mouthpiece from the instrument, you would not be able to play that same low frequency, but you would be able to play a pitch related to the length of the mouthpiece.
   
  There is a lot of misunderstanding about this that I had hoped I explained.
   
  Paul
   
  

flemingml2000 <marklfleming@...> wrote:
          Paul wrote:
"So I think the mistake we make is in thinking there was an INPUT of 
880 hz to force the system to play 880 hz. No, the system was adjusted 
to allow resonation at that point."

I think I can see what's happening. What the reed is doing related to 
the tone produced is always going to be effected by the length of the 
air column. With a reed vibrating at X, a long shank mp will produce a 
different tone than a short shank mp. If you measure the tone with the 
neck on, mp placement will again make a difference as to the tone 
produced even if the reed vibration rate is the same. Put the long 
shank mp on a little further, and you get the same tone out of the neck 
as with the short shank. 

So "putting a tone" into the mp isn't really what is being done, it's 
putting a frequency in that subsequently produces a tone depending on 
the tube length. In the Runyon experiment, a speaker that could drive 
a lot of air may have been able to produce a tone, even a tone of A880, 
but the frequency of the speaker was likely a random and much higher 
frequency.

I don't see that there could be a single magical reed frequency at the 
mp. In fact, when playing my contrabass clarinet, it's really obvious 
that the jaw rattling low tones are because the reed is vibrating so 
slow. It's lowest note is 29.14hz. For those interested, check out 
http://www.contrabass.com/pages/frequency.html

My pitch pipe has a separate reed for each note. Each reed plays the 
same note whether in or out of the pipe (no air column length) and each 
plays only one note. When connected to the "air column" of my alto 
sax, the reeds didn't seem to react to changes in column length. 

I just put got a 4' length of 1/2" copper pipe from the garage, put 
a "neck cork" on it, and put on a tenor mp. I blew a fairly accurate 
low C just by coincidence. But only a C and it was very hard to try to 
change the tone. Using the pitch pipe C reed produced a C that sounded 
like it was coming through a 4' pipe. A produced an A, B a B, etc. 

Simply put, the metal reed on the pitch pipe didn't respond to air 
column feed back. The length of the column seemed to really control 
the cane reed's vibration rate, but not the metal reed. Some of this 
may have been air leakage. The tenor mp squeaked high until it was 
totally sealed. It's a little more difficult to get the pitch pipe to 
seal, but I didn't get the feeling that it would matter.

I'm not sure what to make of this, other than it's a lot more 
complicated than I initially thought.

Mark



                           


Link to Paul's articles from Main page of "Saxgourmet":
		http://www.saxgourmet.com
Listen to Paul's MP3's and view saxophone photos at:
           http://briefcase.yahoo.com/tenorman1952

Paul Coats is the sole US importer of SAXRAX products from 
http://www.saxrax.com 
For SAXRAX products, email Paul at saxraxus@...
       
---------------------------------
Be a better friend, newshound, and know-it-all with Yahoo! Mobile.  Try it now.

The impedance will increase ont the resonances

Le 18 avr. 08 à 20:09, Ed a écrit :

> I need to correct myself. When a resonant frequency is "found", the
> amperage would increase - not decrease. The impedance drops.
>
>
> 

Ed

You're right

At the resonances of the horn, you will see impedance peak ot the  
speaker.

cheers

jacques
Le 18 avr. 08 à 17:52, Ed a écrit :

> Please excuse me as I'm a mechanical engineer who has forgotten most  
> of
> his EE schooling - but wouldn't there be some way to measure the
> current flowing through the speaker to identify resonant "peaks" when
> sweeping through gradually with the frequency? Those peaks perhaps
> identifying the frequency at which the horn is actually tuning at? I
> would expect the amperage to drop when the frequency coming through  
> the
> speaker matched with the air column's natural frequency (similar to  
> how
> you can blow out a stereo speaker more easily if you hit upon just the
> right resonant frequency). Obviously, there would be multiple
> localized peaks to choose from when doing the sweep, but the
> fundamental would stand out beyond the harmonics. These current
> fluctuations would be very subtle and difficult to measure. The
> testing equipment would have to be pretty high-grade.
>
> Think of adjusting the bass port on a speaker enclosure. The saxophone
> in the experiment would be a very large port to a very small speaker.
>
> Ok - I'm thinking about this too much...
>
> --- In MouthpieceWork@yahoogroups.com, "Bob Phillips"
> <rwphillipsidaho@...> wrote:
> >
> > I think that kymarto123 has the right idea. The tone generator is  
> not
> > strongly (enough) coupled to the air column --so it doesn't "play"
> the horn.
> >
> > bob phillips
> >
>
>
>