Vibrato and the Physics of the Clarinet

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Notes on vibrato, along with the physical properties of the clarinet, by Jonathan Cohler and Conrad Josias:

From Conrad Josias:

On Wed, 2 Nov 1994, Timothy Tikker wrote:

I once heard an historic recording of Joachim. His style used vibrato, but only as an ornament, for long-held notes and such - not as a constant. Even if Muhlfeld used it more than Joachim, it still may not have been as much as a modern string player.

Your statement about Joachim's minimal use of vibrato is supported in a parenthetical comment by Brymer that followed the cited passage. It read: "It will be recalled that Joachim played with little or no vibrato."

The only adjective I have to go on from the quoted reminiscence of the viola player who played with Muhlfeld was that it was a "big" vibrato, comparable to that used by the cellist. As you imply, what the term "big" means in terms of modern string-quartet playing style is hard to say. I guess, if the quoted passage is to be believed, the important message is that Muhlfeld played with enough vibrato to make its use apparent to the listener.

Posted on Klarinet Wed, 2 Nov 1994

On Thu, 27 Oct 1994, Ron Everett wrote:

Goodman also studied with Kell, I have been told. To my knowledge, Kell was the first "serious" clarinetist to use vibrato.


In view of the recent discussions about Anton Stadler and his basset clarinet(s), I couldn't resist saying something about another historical clarinetist -- something that relates to your comment about vibrato. I thought you might be interested.

I cite the following passage about Richard Muhlfeld, the clarinetist who inspired Brahms' great chamber works. This quotation is from the book, "Clarinet," by Jack Brymer, which is one of the Yehudi Menuhin Music Guides:

".........A reminiscence of no less a player than Muhlfeld himself seems to suggest that the use of vibrato may have fallen out of fashion temporarily after his day, to return after about thirty years. Just before World War II a question was put to a very old viola player, sometime conductor of the Duke of Devonshire's Orchestra, about the playing of Muhlfeld. The old man had occasionally been called by Joachim to play in his quartet, and on several occasions had played the Brahms Quintet with the great Muhlfeld. Of the clarinetist's playing he was most enthusiastic, saying that three things mainly stuck in his memory. 'He used two clarinets, A and Bb, for the slow movement, to simplify the gypsy section; he had a fiery technique with a warm tone -- and a big vibrato.' Asked again by a startled questioner if he didn't mean to say 'rubato' the old man looked puzzled. 'No' he said, 'vibrato -- much more than Joachim, and as much as the cellist.'"

How about them apples? Brymer concedes that, without a second-party confirmation, the report is without official authority. But he points out that the achievements of exceptional players like Muhlfeld do not always take root in the years that follow their finest period.

Posted on Klarinet Fri, 28 Oct 1994

Conrad Josias

From Jonathan Cohler:

I have been very interested in the vibrato discussion, because this is a subject that I have studied for roughly two decades now. Before I decided to post anything, I dutifully went back and read ALL of the prior postings on the subject starting from January 1994, so that I would have a good frame of reference.

There are many things I would like to comment on, propose, question, disagree with, agree with, and explain, so I will try to do this succinctly and in a sensible order. I believe that the vast majority of the information presented here is new material to the list, so I hope it is not a waste of your time. I have been careful to avoid rehashing material that was completely handled already.

Because the document is somewhat long, I provide a brief outline here for your reference. The complete document follows.


  1. Subjective matters and logical proof.

  2. Objective matters.

  3. Could vibrato possibly produce displeasure in people?

  4. A good vibrato: one that can't be heard??

  5. Evidence for physically pleasant effects of vibrato.


  1. It's so damn difficult! No it's not...

  2. Using the four vibrato production methods in combination.

  3. Two common myths about vibrato.

  4. Abdomen (diaphragm) vibrato does produce pitch variation.


  1. AKA Using vibrato at "appropriate" times -- Brahms, Mozart...

  2. Using no vibrato makes the clarinet blend???


  1. It ain't so hard. And I think we should teach it a lot more.


  1. An ideal tube closed at one end.

  2. The clarinet.

  3. Why the clarinet goes flat when you blow harder.

  4. Cutoff frequency, and all those EVEN harmonics.

  5. Driven systems.

  6. The driving force behind the clarinet and inharmonic partials.

  7. Vibrato emphasizes dissonances?????


  1. Vibrato is an essential tool.

  2. Clarinet's range of tone color is limited.

  3. Everybody loves vibrato (except clarinetists!).

  4. Vibrato is natural, physical and direct.

  5. Brahms, Mozart, all those guys loved it...

Here we go ...



  1. One cannot prove or disprove subjective matters with logic. By definition, something subjective is "proceeding from or taking place within an individual's mind such as to be unaffected by the external world" (American Heritage Dictionary). Therefore, by definition, no logical argument can prove or disprove that vibrato on clarinet sounds "good" or "bad", because whether something sounds "good" or "bad" is totally subjective.

  2. Objective matters, on the other hand are those "based on observable phenomena; presented factually; of or having to do with a material object as distinguished from a mental concept."

  3. If vibrato on the clarinet actually did produce some observable, measurable phenomena that caused "displeasure" to human beings in general, then it follows that over large representative random samplings of people, the percentage of people that found vibrato "displeasing" should be a constant. Based on my long experience and various informal surveys, I have discovered (and I challenge anyone to disprove this) that the percentage of non-clarinetists in the general population (including all other musicians) that find vibrato on the clarinet "displeasing" is vanishingly small. On the other hand, I find that the vast majority of clarinetists do not like vibrato.

    Clearly, the clarinetist population is not a representative sampling in this regard. Why should this be?

    It seems that the most likely explanation is that people do and think what their teachers tell them to (to a first-order approximation) and there has been a long, well-documented and adamant tradition of teaching that vibrato on the clarinet is bad. The reasons behind this teaching have been wide and varied and they have been discussed at length on this list, so I won't go into them here (although I found the discussion of the anti black music sentiment from the 40s and 50s particularly interesting).

    Therefore, people are certainly free to feel--because it is a purely subjective issue--that clarinet vibrato is "displeasing" in various settings, but there is certainly NO physical, objective or observable basis for this feeling. If there were, it wouldn't be only clarinetists that feel this way. Rather it arises--as do many of peoples' feelings, beliefs, morals, and the like--out of how clarinetists were raised and taught.
  4. While our thinking on the vibrato issue has advanced marginally over the past fifty years, in that many clarinetists don't issue blanket condemnations anymore, the thinking hasn't changed as much as it seems on the surface. In reading through, the piles of vibrato postings, over and over again I see statements such as: "I enjoy some vibrato when it is subtle, but I personally do not use it unless it is specifically asked for in the score," or "I find the most pleasing is a very subtle, almost undetectable, slow vibrato on the key note in a phrase."

    Have you ever heard a violinist, cellist, soprano, oboist, flutist or the like saying anything like this? Probably not. You probably have heard discussions, of how to produce vibrato, and where to vary the speed, amplitude or shape of the vibrato, but not how to make it unnoticeable.

    Liking one particular kind of vibrato in a very limited section of a particular kind of music, is not really much different from disliking vibrato. I think the slight shift in attitude today comes from the fact that it is more politically correct today to say that you like, and even sometimes use, vibrato, but the fact is that the vast majority of clarinetists still do not use, and not coincidentally, don't understand vibrato. We often dislike and avoid the things we don't understand.

  5. As mentioned in other postings, I believe there is substantial statistical evidence (across many musics around the world, across at least two hundred years) to support the hypothesis that vibrato produces physical phenomena of some sort that do indeed induce sympathetic pleasurable response in the listener.



  1. Martin Brown said, "I think the reason that relatively few clarinet players use vibrato is that it's so damn difficult! Compared to a string instrument where you just wiggle your finger, ..."

    Learning to do vibrato on the clarinet is no more difficult than learning to play a chromatic scale. It requires careful instruction and careful practice. And being married to a concert violinist, I can tell you that learning string vibrato is much more difficult and takes many more years of practice. Typically, string students take anywhere from five to ten years to begin producing a decent, stable, good sounding vibrato. On the clarinet, I have found that students can produce a decent vibrato within two years.

  2. I won't rehash the entire discussion on the three or four methods of vibrato production (depending on how you count), because they have all been mentioned. What was not discussed very much except in passing in a quoted passage from Jack Brymer, was that the most important step in creating a flexible and expressive vibrato is being able to integrate all of the various methods simultaneously, and pass seamlessly from one to another. Depending on the basic impedance(s) of the note(s) being played, the pitch flexibility of the note, as well as the dynamic level, range, and desired sound quality, one can combine lip, throat and diaphragm (abdomen) vibrato in various quantities. Always doing one kind or another at a fixed speed generates just as uninteresting a sound as a constant non-vibrato tone.

  3. Two common myths: (1) vibrato masks a bad sound, (2) vibrato masks bad intonation.

    Tone quality as observed by listeners (and there have been many research papers on this subject) is basically a function of harmonic content. Vibrato modulates the amplitude and frequency of a note slightly. In a classical vibrato, one attempts to "keep the note in focus" at all times during the vibrato. Keeping the note in focus translates directly into the measurable act of keeping the harmonic content relatively constant. In a jazz context, on the other hand, one purposely allows the note to go in and out of focus, which dramatically varies the tone quality of the note over the course of the vibrato. Therefore, the vibrato is used in jazz to actually exaggerate the "badness" of the sound. That's what makes it sound jazzy. In classical vibrato (at least by my definition), there is no change in the "tone quality" during a vibrato. And certainly, there is no way that a vibrato can enhance the tone quality. In fact, one of the difficult parts about classical vibrato is making sure that the sound always stays in focus.

    The perceived intonation of a note with vibrato is the average pitch of the vibrato. If the average is high the note will sound sharp. If the average is low it will sound flat. The vibrato does nothing to mask out of tune playing. (The only exception to this statement, is perhaps at the very onset of a note. If you hear a note is out of tune when you play it, and adjust the center pitch to the correct pitch within a half cycle of the vibrato, it is very hard for the listener to detect this change. Of course, this is basically true without vibrato as well.)

  4. Many people noted that abdomen (diaphragm) vibrato produces only amplitude variation and not pitch variation. This is not entirely true as can be verified with a Fourier analyzer. I'll discuss the physics in more detail below, but for here suffice it say that as one blows louder on the clarinet the perceived pitch gets flatter. Even assuming that the player has a nice firm embouchure, this is still the case. The amount of pitch change will depend directly on the amplitude of pressure variations in the vibrato. It is true, that this pitch variation will generally be smaller for a given amount of physical effort compared to lip vibrato. But nonetheless there IS a pitch change. (See below for the physics of why.)



  1. Many people noted that using vibrato is OK sometimes, but not in Mozart! Other people feel it shouldn't be used in Brahms. And on it goes. If people feel it's OK in general, but not in particular instances, then what are the reasons??? Among all those postings, I didn't see a single reason listed other than "that's my opinion." Again, we are back to the subjective.

    I prefer to take a more objective look at this issue. What did the composer want, or specify, or not specify (thereby leaving it up to the performer), and what were the practices of the day, and particularly of the performers for whom the composer wrote the work? Here's an interesting note on the Brahms clarinet works.

    The quotation from Brymer's book on Muhlfeld's relatively heavy use of vibrato has already been mentioned several times. What has not been mentioned is the following:

    • Muhlfeld was not a clarinetist originally.

    • He entered the Meiningen orchestra in 1873 as its concertmaster. Yup, that's right, he was a violinist.

    • He taught himself to play the clarinet (i.e. no teacher prejudices)

    • He became principal clarinetist of the orchestra in 1876

    • Hans von Bulow became conductor of the orchestra in 1880 and later appointed Muhlfeld as the assistant conductor.

    • Brahms first noticed Muhlfeld in a trip to hear the orchestra in 1890. This was at a point in Brahms life when he had decided not to compose anymore. And he had certainly heard all of the great European clarinetists of the day in his travels.

    • In March 1891, he wrote to Clara Schumann "It is impossible to play the clarinet better than Herr Muhlfeld does here."

    • In July 1891, he wrote to Clara Schumann the Muhlfeld is "the best wind player I know."

    Given that Muhlfeld was a violinist/conductor/self-taught clarinetist, it seems consistent that he would use a vibrato. Further, given that Brahms was a jaded, retiring composer who had heard all the great players of Europe by the time he was enraptured with Muhlfeld, it is hard to believe that he was captured by Muhlfeld's technique alone. His use of the terms "Fraulein Klarinette" and "prima donna" to describe Muhlfeld also implies that he viewed him as an operatic soprano.

    All of this points to the likely conclusion, that it was, in fact, the very use of a very noticeable, continuous vibrato that is largely responsible for inspiring Brahms to write the great clarinet works.

    Thus the next time you hear yourself saying, "I don't think one should use vibrato in Brahms," stop and think what Brahms might say.

    As for Mozart, last time I spoke with Charlie Neidich, he gave me some information, of which I cannot recall the details right now, that indicates Stadler may have used a noticeable continuous vibrato as well! I'll get the details from Charlie, if people are interested.

  2. One of the strangest and most illogical statements I have read in this discussion is that orchestral woodwind sections produce a homogeneous sound, because the clarinet does not use vibrato. There is certainly observable physical evidence to prove the opposite of this statement. The fact that the clarinet uses no vibrato in a section of instruments that all use vibrato makes the clarinet sound more easily distinguishable by the listener. Similarly, if one instrument in a group attacks notes in a different fashion, it will be more easily distinguished by the listener. All of this has been studied and proven in PhD theses. Now, that says nothing of the aesthetic, subjective judgment as to whether it is better to have the clarinet sound stand out from the woodwind section. But it is certain that lack of vibrato on the clarinet WILL make it stand out from a group of woodwind instruments using vibrato. Imagine a string quartet where only the first violinist uses no vibrato. Does that make him blend better? You may like the effect, but it is certainly not blending. In fact, when string quartets work on blending there sound, they spend many hours practicing to match vibrato (speed, intensity, width, and shape--not all vibrato is sinusoidal).



Now we come to the problem which was nailed on the head by Nichelle Crocker. Teachers don't teach vibrato. This is unfortunate, because vibrato is just like any other technical aspect of playing an instrument. It needs to be learned. It is not a natural act. If it was, you would see monkeys playing clarinet. It is easy to teach, and easy to learn (Easy is of course a relative term. Let's say easy compared to string vibrato.) But without practice and proper technique, you'll waste an awful lot of time trying to figure out how to do it, and most people will never figure out how to do it well.

I have a few recommendations for rectifying this gaping hole in clarinet training that currently exists worldwide:

  • Clarinet teachers should start teaching vibrato. Especially, at the college level.

  • Even if you don't like to use vibrato yourself, you should not deprive your students of basic technique, because of your own prejudices.

  • If you don't know how to do vibrato, find someone who does and start learning.

  • Let's have a regular session at every ICA conference from now on on vibrato production, usage, techniques, etc...

  • While I'm on my soap box, let's add circular breathing and double tonguing to the list. These are also badly neglected on the clarinet.



There was some partially correct (and therefore partially incorrect) discussion of the physics of clarinets during the vibrato discussion. Having been a physics major in college, and having done a fair amount of study of the physics of musical instruments, I wanted to clarify the basics.

  1. An ideal straight tube closed at one end and open at the other end has only odd harmonic resonant modes. In other words, the modes of the system are f, 3f, 5f, etc. where f is the fundamental frequency defined by f=v/4L, v is the velocity of sound in air, and L is the length of the tube.

  2. The clarinet is NOT an ideal straight tube. The major differences are the flared bell and the tone holes.

  3. The flared bell and the tone holes conspire to make all the upper tube modes of the clarinet flat. As you move to higher modes they get more and more flat. This is the reason the clarinet goes flatter as you blow harder. As you blow harder, you are adding more and more of the upper partials to the sound and the entire regime of oscillation is dragged slightly downward in frequency by the flat upper tube modes which are now more influential in the "regime." This is not true of most other instruments.

  4. The tone holes create another deviation from the ideal tube. For frequencies with wavelengths that are roughly the same size as the holes, the clarinet no longer behaves like a tube closed at one end. This frequency cutoff point (called the "cutoff frequency") is around 1500Hz or in musical terms that is around a double high G# on the clarinet. Above this cutoff point the clarinet spectrum has roughly equal amounts of even and odd partials. So the odd partial description of the clarinet really only holds true up to 1500Hz, which, for example, is roughly the fundamental frequency of a double high G#.

    As another example, take the third-space C on the clarinet (concert Bb). This is a frequency of 466Hz. The first partial of substantial amplitude will be at 3*466 or 1400Hz minus a bit After that there will be substantial component of 4*466 (minus a bit more), then 5*466, etc. You can see that the odd- harmonic-dominant description is really VERY inaccurate for MOST of the range of the clarinet.

  5. It IS true that when you drive any physical system with a sinusoidal input, it will vibrate ONLY at that frequency. The amplitude of that vibration will be a function of the driving force and the Q (or resonance response curve) of the system. If the system has a sharp resonance at or near the driving frequency, you will get a large amplitude output. If you drive it at a frequency far away from the sharp resonance, you will get a low amplitude output.

  6. In the case of the clarinet, the driving force is not a simple sine wave, but a combination of sine waves that changes with blowing pressure. When you play very soft on the clarinet the reed vibrates in a very sinusoidal way (sounding similar to a flute), you begin to get more and more of the upper partials, and when the reed begins to hit the mouthpiece (at a dynamic that most people refer to as mf) more high partials are introduced in to the sound making it brighter and buzzier. Because the clarinet is a coupled vibrating system (reed/air-column) the reed influences the air-column and the air-column influences the reed.


These are last, and definitely least important, but now finally to my subjective opinions (I'll be brief for those who care). I preface everything by IMHO...

  1. I believe that vibrato, in all its forms, used both subtly and overtly, big and small, wide and narrow, fast and slow, is an essential tool in playing the clarinet, without which one can achieve only a small fraction of the expressive capabilities of the clarinet.

  2. With a given reed, mouthpiece, clarinet and dynamic level, the range of tone colors (leaving out special effects such as flutter tonguing) that are achievable without vibrato are VERY limited. (This, by the way, I believe is fairly well documented in the acoustics literature, so it probably belongs up in my discussion of physics, but it's too late at night to change now.)

  3. Audiences of non-musicians, and non-clarinetist musicians overwhelmingly prefer and enjoy the sound of vibrato on the clarinet. These people constitute 99% of the audiences that we play for. We should listen to what they are saying.

  4. Vibrato makes a natural, physical, direct connection to the listener.

  5. Brahms loved it, Mozart loved it and that's good enough for me.

  6. Hope you got something out of this. Looking forward to your comments, flames and the like.

Jonathan Cohler
Posted on Klarinet, 7 Feb 1995.

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