a theory of vibrato

[robcat2075]

a cello player writes this...

...The individual instrument resonates in response to all the frequencies transmitted to the corpus (body) through the bridge. but the amplitude of the frequencies passing into the air and to listeners depends on the amplitude/frequency characteristics of each particular instrument.

The player's vibrato spreads the breadth of the fundamental (fingered) tone's frequency and thus the also of its overtone frequencies. This can activate some higher (and lower) sound peaks depending on the instrument's resonance spectrum, thus creating additional richness, "projection" and apparent loudness of the sound.

Good players will will control their vibrato to (try to) produce the sound they want from the instrument they are playing by adjusting the breadth and speed of vibrato motion. Experienced players trying an unfamiliar instrument may have to adjust their vibrato to the nature of the instrument to get the desired sound from it (if it is possible at all).

The first paragraph is common stuff.

The second and third assert something I've wondered about... that the vibrato actually alters the timbre rather than merely being perceived as warmer, richer, etc...

[timothy42b]

That makes sense to me.

The upper harmonics of our sound don't line up quite the same as the resonances of the horn - one set is mathematical and one isn't. We can alter timbre by playing above or below pitch center, and it makes sense that vibrato above and below can result in reinforcement of some higher harmonics that otherwise don't sound as well.

Need sunglasses, though, we get dirty looks when we use it.

[boneagain]

That makes sense to me.

The upper harmonics of our sound don't line up quite the same as the resonances of the horn - one set is mathematical and one isn't. We can alter timbre by playing above or below pitch center, and it makes sense that vibrato above and below can result in reinforcement of some higher harmonics that otherwise don't sound as well.

Need sunglasses, though, we get dirty looks when we use it.

Not if you use it in the right place

[boneagain]

I'm working on some Fast Fourier (FF) stuff for another thread, so have driven full tilt into a BUNCH of weeds. This thread and Tim's comment bring to mind a really nice table Micah Everett posted at Ole Miss. It gives partials and their tuning relative to actual harmonics. (I just saw a pithy comment elsewhere of "All harmonics are partials, but not all partials are harmonics... handy... don't yet have solid citations for the accuracy of the statemment.)

This begs for some FF stuff, but would be even harder to control for than the other thread ("Real" bass trombones... one straight-as-possible note at a time, NV, etc.) IF the controls can be managed it would be pretty interesting to see.... hmmm....

[robcat2075]

Real or merely perceived? I'm not sure either way, yet.

I think if we quizzed trombone teachers, people whose job is to explain trombone playing, and highly accomplished players... they would speak of vibrato in terms like "an expressive ornament", a concept completely absent from the comment I quoted above.

That is the way I've always heard brass players discuss vibrato. I don't think I've ever heard them identify it as a timbral modification.

Perhaps the outcome is genuinely different. Maybe because the mechanics of tone production are so different, the continual variation of the pitch has some result on the vibrating surfaces of a cello that it does not on a trombone. Vibrating surfaces are a minor factor in trombone sound production anyway.

[boneagain]

Real or merely perceived? I'm not sure either way, yet.

I think if we quizzed trombone teachers, people whose job is to explain trombone playing, and highly accomplished players... they would speak of vibrato in terms like "an expressive ornament", a concept completely absent from the comment I quoted above.

That is the way I've always heard brass players discuss vibrato. I don't think I've ever heard them identify it as a timbral modification.

Perhaps the outcome is genuinely different. Maybe because the mechanics of tone production are so different, the continual variation of the pitch has some result on the vibrating surfaces of a cello that it does not on a trombone. Vibrating surfaces are a minor factor in trombone sound production anyway.

I was just thinking about the "vibrating surfaces" aspect, with the same "minor factor" assumption. But would this effect require the vibrating surfaces, or could it also have an effect with vibrations already introduced into the room?

IF we could measure the effects I suspect we would find it to be orders of magnitude smaller than the very noticeable vibrato itself. That does not mean it is not a real effect... just that it would be sublte.

[Lastbone]

I thoroughly appreciate the cello quote -- this helps me understand how differently strings work from winds.

For brass, vibrato has always been a bit of a mysterious issue, especially when we see so many obviously wrong approaches in use. How often do we see trumpets rocking their fingers on the valves to create a vibrato effect? I know a baritone player who shakes his whole horn for vibrato, and another who makes a chewing motion with his jaw. Makes jazzers who wiggle the slide around seem like accomplished classical players in comparison.

My wife is a flute player, and flute pedagogy spends a tremendous amount of time on vibrato, as does vocal pedagogy, but little of this translates easily to brass. I guess this gives me something else to ponder on those long and sleepless winter nights...

[Posaunus]

" ... jazzers who wiggle the slide around ... "

I've always loved that effect. Growing up as a big band fan/player, and a jazz lover (without much formal education), I never knew that trombones used any other sort of vibrato. Only decades later did I learn about "jaw vibrato." I now use both techniques - I hope in the appropriate situations! What a great way to enhance the music we produce.

[robcat2075]

I was just thinking about the "vibrating surfaces" aspect, with the same "minor factor" assumption. But would this effect require the vibrating surfaces, or could it also have an effect with vibrations already introduced into the room?

IF we could measure the effects I suspect we would find it to be orders of magnitude smaller than the very noticeable vibrato itself. That does not mean it is not a real effect... just that it would be sublte.

Yes, I think you will need one of those amps that goes to 11 before vibrating surfaces in the room amount to anything to consider.

Rooms ARE a factor, of course, due to reverberation or lack of it, but that is the sound bouncing OFF the surfaces rather than some modification to the sound by the surface's vibration.

Does the room air itself behave any differently with vibrato?


The front and backs of string instruments, however, are very dynamic things with complex modes of vibration that have been documented to be crucial to the final sound.

Behind The Craft: Violin Plate Tuning

[boneagain]

Does the room air itself behave any differently with vibrato?

... too!

The front and backs of string instruments, however, are very dynamic things with complex modes of vibration that have been documented to be crucial to the final sound.

My personal experience is that a classical guitar is a lapful of vibrating stuff, while a trombone requires paying attention to notice. OTOH I attribute the presence, or lack, of feedback behind the bell to instrument vibration. There has to be SOME reason I hear myself better behind the horn on some instruments than others. I have one or two notes on my horn that make my bell ring very audibly. But I think the most that such effects could do is absorb tiny bits of energy at different points in the spectrum.

And on the third hand, the primary transfer of sound from the strings to the air is via the body on strings. The air column itself is the very dominant transfer of sound from the lips to the room on brass. Another theoretical reason why vibrato might NOT do much, if anything, for the sound timbre on brass.

Interesting stuff, Rob!

[robcat2075]

And on the third hand...

To paraphrase Harry Truman, " Somebody bring me a physicist with one hand!"

[timothy42b]

Rooms ARE a factor, of course, due to reverberation or lack of it, but that is the sound bouncing OFF the surfaces rather than some modification to the sound by the surface's vibration.

Does the room air itself behave any differently with vibrato?

About 20 years back I was at a festival in a St Paul MN park.

One of the musicians was a solo clarinet player inside a large space, very high ceiling and with a very live cinder brick wall near an open space, kind of modern architecture.

It sounded like he adjusted the speed of his vibrato to account for the reverb off that one wall. The effect was awesome and he drew quite a crowd. That may not be what really happened but it was my perception.

[robcat2075]

...One of the musicians was a solo clarinet player inside a large space, very high ceiling and with a very live cinder brick wall near an open space, kind of modern architecture.

It sounded like he adjusted the speed of his vibrato to account for the reverb off that one wall. The effect was awesome and he drew quite a crowd. That may not be what really happened but it was my perception.

I'm imagining something like a phaser on Star Trek.

My personal experience is that a classical guitar is a lapful of vibrating stuff, while a trombone requires paying attention to notice.

Very true of the cello too. When i play my cello i can feel it vibrating on my sternum and even on my knees.

And there is something very alluring about adding vibrato on cello that I don't sense on trombone.

It is nearly irresistible, there is something about it that makes you want to do it more. When I watch teachers talking to students at masterclasses, I've never seen one suggest less vibrato. Real players would be vibrating every note in a run if they could.

Here's the closest apples-to-apples comparison I can contrive. There's something about it that works on cello that isn't there on trombone.

Casals:



Pryor:

[Doug Elliott]

Pryor is using more of a breath vibrato or tremolo without the pitch variation typical in other vibrators.
Fortunately that unpleasant style is rare now, although I have heard a recording of Gunhlild Carling doing it..
at 7:04

[robcat2075]

This guy describes the vibrato as "color". Which is rather like "timbre".

Here is an interesting bit in which he plays the same phrase, first without vibrato and then with vibrato.



Also notice the loud whack every time he lands a finger.