Practicing your sax without overtones

[jbtsax]

A recent thread was entitled practicing overtones without your sax, and so this is a play on words. Does anyone know how to play your sax and not create overtones in the sound? Any guesses?

 

[BigMartin]

Take up the flute? (you get less of them anyway, I think).

 

[spike]

Take the mouthpiece out your mouth perhaps ?

 

[Colin the Bear]

Drumsticks?

 

[jbtsax]

This is fun. I'll give you a hint. You are actually playing your saxophone, but the notes are only sounding the fundamental when you do so. The correct answer is really quite simple. Somebody should get it now.

 

[spike]

Like I said above I can only think you play the pads.

 

[kevgermany]

I'm intrigued. Cos what you're saying is you can only play a single octave

 

[spike]

You've got to put a deadline on this for last entries jbt. The suspense is mortifying

 

[kevgermany]

You've got to put a deadline on this for last entries jbt. The suspense is mortifying

Pun intended?

 

[spike]

Must've been the last horror movie at 3 this morning . . .

 

[BigMartin]

Only thing I can think of is take the mouthpiece off and sing the right note into the body.. Not sure you wouldn't still get some higher partials, though.

 

[Clivey]

Underwater??

 

[jbtsax]

The simple answer is to play pianissimo which produces what is very close to a "sine wave".

". . .starting from pianissimo playing levels there are virtually no harmonics present in the tone beyond the fundamental; then for every doubling in the amplitude of the fundamental component, harmonic 2 increases from its initial tiny value by a factor of 2 to the 2nd power = 4; similarly harmonic 3 will grow by a factor of 2 to the 3rd power = 8 for each doubling of the fundamental."

As the quote above describes, the harmonics then play "catch up" in as the fundamental gets louder as one crescendos. Then another interesting phenomenon occurs.

"Once the blowing pressure is raised to the point where the reed is blown entirely closed for a portion of each cycle of its oscillation, [referred to as "beating"] the player notices a change of feel, the listener notices a change of tone, and the higher partials grow in a way that parallels the growth of the fundamental.

It is easy to test this for yourself. Just play a note starting pianissimo and slowly crescendo watching for a sudden change in the tone and feeling of the note when the reed begins to "beat", usually around mf in my experience.

 

[spike]

Having a mind blowing afternoon out here in the boonies - Must admit I can't detect the moment the reed begins to "beat". I can certainly hear an increase in the harmonic content of whichever note I play but that "beating" point beats me. I shall Percy Vere.

 

[Young Col]

JBT, your quote does say "virtually no harmonics". I think it has to be something like pppp to produce only a pure sine wave in a resonating cone or tube. Audible pure sine waves sound very dull and lifeless precisely because they have no harmonics to enrich them.

I would have thought it was much more than mf when the reed starts to close completely against the mouthpiece. I know that change of tone but I don't think it is that sudden and I don't associate it with the reed closing, rather that you are hearing more of the whole sound including higher harmonics at louder volume (personally I don't like the term "beating" as it's usually associated with the intermodulation product, being a sum or difference, of two or more independent frequencies mixing, eg F1+F2=F3). I think the point at which the reed closes against the mouthpiece for part of the cycle is getting close to the point at which it stops oscillating - and hence producing sound - altogether.

 

[jbtsax]

Your points are well taken. The term "beating" unfortunately is the one acoustics scientists use to describe the motion of the reed when the pressure is such that it momentarily closes the tip of the mouthpiece. Another interesting bit of acoustics is that on clarinet the reed is closed 50% of the time and open 50% of the time in the "beating" cycle. On conical instruments however the closing percentage is less than 50% and approximately equal to the ratio of the truncation of the cone. This means that the time the reed is closed on the saxophone is equal to the time the soundwave would take travel to the apex of "imaginary" missing cone and back.

I did find a bit more about the reed "beating" in Nederveen's book Acoustic Aspects of Woodwind Instruments.

The reed moves "sinusoidally" at mouth pressures between one-third and one-half of the maximum pressure; "beating" starts at pressures larger than one-half the maximum value (Kergomard 1995).

The "maximum pressure" is that which closes the reed permanently. Below is an illustration from the UNSW Acoustics website that shows the pressure "curve" at various dynamic levels.

 

[BrianJoeSandy]

Here is a demo: http://youtu.be/yvm_dUJmNkA
I can no longer find the Auto Tuner on the web, but have a copy if anyone is interested. It was free when it was available.

 

[jbtsax]

Thank you for that link. I have wanted to find a spectrograph that would show the harmonics in real time as you play. That is a great visual representation of what this thread is about. That is actually a written D2 on an alto sax (F concert). It is interesting to see the tiny D1 shown on the screen that has given most of its energy to D2 because the octave vent was opened. It has not gone away completely in the sound, but the fundamental D2 has clearly taken over.

 

[saxplorer]

This Android app is fun to watch while blowing long notes ;-)

https://play.google.com/store/apps/details?id=radonsoft.net.spectralviewpro

Gives a rather good visualisation of sound: harmonics clearly visible as shown in the middle image shown on that link.