overtones heard in tubas' (and other instruments') resonance

[Dubby]

On this same vein, wouldn't multi phonics be included as well? Something like Fnugg by Baadsvik

[Donn]

But tuning might have something to do with how it sounds - am I right, the overtones actually are not guaranteed to come out exactly in tune (by any temperament), and of course that would be a factor. I'm not talking about radical differences, but a little can make a big difference.

I don't understand the physical principles, why these overtone frequencies are so reliably formed. Evidently they're subject to the acoustic principles of the instrument, accounting for a lot of why different instruments sound different - for example a clarinet's low register sounds distinctively hollow due to significant loss of even partials. That suggests to me that intonation issues would apply to the harmonics as well *, but mainly my impression is that overtone tuning is more a matter of playing technique.

* But I don't understand why the actual series doesn't match the horn's resonating frequencies: a Bb in the bass staff produces (I'm told) Bb-Bb-F-Bb-D-F to the top of the treble staff, though we know that as the 4th partial on a BBb tuba and by that logic it would produce Bb-D-F-?-Bb-..., or Bb-Eb-G-Bb-?-... on an Eb tuba where it's 3rd partial.

[Dan Schultz]

On this same vein, wouldn't multi phonics be included as well? Something like Fnugg by Baadsvik

I view multi-phonics as being something quite different and actually very easy to do. It's just a matter of introducing both a voice hum and a lip vibration into the horn at the same time.

[michael_glenn]

The only experience I have had with this --- on certain contrabass tubas, when playing the open C or Bb in the staff at FFFF, the C or Bb an octave below can be slightly heard.

Physics is a weird subject.

[hup_d_dup]

I view multi-phonics as being something quite different and actually very easy to do. It's just a matter of introducing both a voice hum and a lip vibration into the horn at the same time.

This is one way to get it done. But this method is not the same as the one used in the video, in which the secondary pitches are restricted to the harmonic frequencies of the fundamental tone.

Tuvan throat singers have been developing this technique since pre-history.

http://www.alashensemble.com" target="_blank

Hup

[Doug Elliott]

Another odd thing that happens - particularly when there is a pair of piccolo trumpets playing in harmony...

...that tone is the DIFFERENCE between the frequencies of the two harmonized piccolo trumpet pitches.
... I believe it must be the difference in the frequencies of the two piccolo trumpet harmonized pitches.

Well, yes, that's called a Difference Tone and that's exactly what it is. The waves of two higher frequencies coincide at a rate equal to the difference between them and that produces the sound of that slower vibration, sometimes quite strongly.

[tbn.al]

Thanks Doug. Here is an explanation complete with sound file.

http://www.sfu.ca/sonic-studio/handbook ... _Tone.html" target="_blank

[Donn]

The harmonics (overtones) present in a musical tone are PERFECTLY in tune with their fundamental as that is what is generating them. The fundamental pitch dictates the pitch of the harmonics is also producing. There is no variance.

What does a Peterson Stroboscopic Tuner measure, then?

from http://en.wikipedia.org/wiki/Electronic_tuner

As the disc has multiple bands, each with different spacings, each band can be read for different partials within one note. As such, extremely fine tuning can be obtained, because the user can tune to a particular partial within a given note.

[Donn]

I got a glimpse of one 30 years ago, I'm sure someone around here is more familiar with it. I believe the bands move independently, and even if graphics depict octaves (and I think they don't), well, octaves are harmonics.

The Android version on my cellular phone shows the partials tuning together, and there seems to be a theory that this is assured by "mode locking", but I don't have complete faith in this application - doubt the built in microphone is adequate, for one thing. The iPhone application comes from Peterson and I'm told it's better.

[Donn]

If you can find any evidence to support your theory that the harmonics (overtones) present in sound are not by their very nature in perfect tune with their creating fundamental tone, please share it.

Well, present in sound, see Inharmonicity

However, in stringed instruments such as the piano, violin, and guitar, or in some Indian drums such as tabla, the overtones are close to—or in some cases, quite exactly—whole number multiples of the fundamental frequency. Any departure from this ideal harmonic series is known as inharmonicity. The less elastic the strings are (that is, the shorter, thicker, smaller tension or stiffer they are), the more inharmonicity they exhibit.

So bass strings on a small piano, for example, have physical issues that interfere with the production of ideal overtones, and that's where they come from - the overtones don't somehow inherently arise from the fundamental, the string has to vibrate at the harmonic. The "mode locking" effect evidently pulls the harmonics together in wind instruments, but this might be a question of degree. If no one has ever sat down with a strobe tuner and worked on partials, then sure, for practical purposes they may as well be regarded as fixed, but I thought that was actually rather common practice back when there were strobe tuners in band rooms.

[DonShirer]

The overtone series generated by a tuba (or any instrument) is a complex result of the resonances in the bugle (generally a strong fundamental and decreasingly loud harmonics) and the radiating ability of the bell (generally bell size is a fraction of a fundamental wavelength so it radiates poorly at lower frequencies but increases to a level radiative ability at higher frequencies). Their combination can produce a series in which the volume of each overtone (to pick an example) increases from the fundamental to the third or fourth harmonic and then starts decreasing again.

Nevertheless, unless the fundamental is very weak most listeners would hear this as a tone at the fundamental pitch with the shape of the overtone series producing the effect usually described as "tone color". (Some organ pedal mixtures include no fundamental, but listeners interpolate it from the provided 2d, 3d and 4th harmonics!) From the discussion in previous responses, it appears that some people may be able to discern an individual overtone amidst the complex note, especially if the particular instrument they are listening to strongly over-emphasizes one of the higher harmonics. Myself, I don't look for individual overtones, but prefer to consider the complex tone "color" or "quality" as a whole.

[toobagrowl]

Speaking of overtones, we should also speak about the shape of sounds. Sine waves, triangle waves, square waves, and sawtooth waves. I think this applies to tubas, and music in general.

Some videos on how different sound waves and overtones/harmonics works:

https://www.youtube.com/watch?v=YsZKvLnf7wU

https://www.youtube.com/watch?v=j2uB4nKzGlg

https://www.youtube.com/watch?v=L5MMcVzhDRI

[Three Valves]

I was entranced by both the singers voice as well as her cleavage.

[Doug Elliott]

I have read that the human voice is distinctly NOT "perfectly" harmonic. There's nothing in the resonance that would lead me to believe that it would be. There are harmonics but not necessarily multiples of the fundamental.

[NCSUSousa]

Link 8 on the Inharmonicity wiki page is to a UNSW webpage on acoustics and sound spectra.

I like the last paragraph from the UNSW sound spectra page -

"Here are some general statements about spectra:

• bowed strings and winds have harmonic spectra
  plucked strings have almost harmonic spectra
  tuned percusion have approximately harmonic spectra
  untuned percusion have nonharmonic spectra
  the low register of the clarinet has mainly odd harmonics
  bowed strings have harmonics that decrease relatively slowly with frequency
  brass instruments often have spectra whose harmonics have amplitudes that increase with frequency and then decrease.

To say anything that is much more specific than that is misleading."

[aqualung]

Note the image of the strobe wheel on the wiki article. The divisions are always 1/2 of the larger band. Octaves.

I went out and borrowed a Strobotuner today. It is the "newer" model, with wood side panels and a larger window.
The older model indeed only showed octaves. This one shows all the harmonics up to #10.
I tried out a variety of low brass instruments, including some that are quite noticeably out of tune with themselves.
But in every case, all the harmonics of any single pitch were true.