INTONATION
Playing in tune is not solely the result of peering at a strobe/tuner, aligning the pointer to the center mark and assuming all further intonation problems on the instrument are solved. Adjusting the tuning of one or two notes by sight is not the answer. I have witnessed countless band directors - in pre-concert warm-ups - walk to various members of the ensemble showing - for only two to three seconds - the tuner to his performers and they, in turn, assume as long as the pitch needle is aligned, they are in tune and all is well with the remaining notes. In many cases, the performance turned out to be horribly out of tune. So, what is the answer? Little time is spent in public school music training the ear. Most of the time is spent preparing programs and contest music. Students do little more than PLAY the same instrumental part over and over until the program has been performed, or the regional contest rehearsals and performances are finished.
These young players supposedly getting a music education, have had little or no screening done to determine whether they have a good sense of pitch, or in general, a good ear. Many may have very poor ear perception and a poor sense of pitch; and some of these same players may not be able to sing a simple melody accurately.
Not all students sing in a choir, and not all choir singing teaches good pitch management. There should be some type of long term individual or group sessions on ear training to adequately teach pitch relationships. This in turn would then be applied to each students' individual instrument with some assurance that he/she would be aware and listening for pitch variations and making the necessary adjustments.
It appears that public school ensemble playing or singing is the total expression of a music education. We are doing our young people a great disservice by assuming this is the sum total of the 'musical experience' and the art of music. Out of the group of students within a particular program there may be a few that are inspired to consider a career in music, but find that the training they had in public school falls far short of having providing them with the skill(s) they need to pursue this career. If music education programs provided considerable attention to training the ear as well as performing on an instrument, each student would most certainly be far more competent to consider majoring in music at some college, university or conservatory.
Besides understanding and employing proper breath support, a well adjusted reed (make and strength do not matter,) and an instrument in good working order, other factors enter into playing in tune on the clarinet - namely, listening. Early training in singing intervals in solfège would be the ideal route, but we cannot assume that this would be the case in the music education or even in private teaching today. The student must be made aware of pitch difference within his/her own playing as well as in other collaborative endeavors, making adjustments as necessary - but never at the sacrifice of good tone.
No clarinet can be built perfectly in tune. The Rossi clarinet comes very close to having optimum intonation.
Clarinet plays sharp
If the clarinet plays sharp, the barrel can be pulled out a little. Beyond 2 to 3 millimeters, the throat notes suffer immensely and play very flat. Some players insist that spacers or rings should be inserted in the barrel to take up the extra space in the socket. I have never ascribed to this practice and have had little or no problems tuning; it is all a matter of personal preference. I can say this however, having tried the 'spacer' technique years ago, I found that the resistance in the instrument changed drastically.
Clarinet plays flat
The barrel should be pushed in as far as it will go or a shorter barrel can be used. In making the shorter barrel decision, one must try various barrels of the shorter length testing them for good response and tone. Don't select a shorter barrel only for the length and sacrifice good playing quality.
Do it Yourself Intonation Adjustments
There is no substitute for clarinet adjustments being made by a good craftsman. Sometimes they are few, and hard to find. Certain classic notes on the instrument are true to their poor intonation, and the following hint can make a critical difference. A very thin film of shellac or even clear nail polish can be applied to the upper side of the tone hole to bring the pitch down. For example: Chalumeau b which on many clarinets - especially older vintage - is quite sharp, can be lowered by applying a thin coat of shellac or nail polish to the upper side of the tone hole above the b fingering i.e. the Bb tone hole. If the shellac or nail polish suggestion scares you, try a small piece of electrical tape, it does the same thing, and can be removed if desired results aren't obtained. If you hesitate to try any of the above in the fear of damaging your instrument, DON'T DO IT. I have successfully applied some of these techniques over the years and have had much practice and success in doing so, but in the long run one must be wise and careful.
In summary of all said in this discussion of intonation, it is up to each player to make his/her own instrument play in tune. The ear, fingers and instrument all play an important role in playing in tune. Remember: "It takes two to play in tune."