About 7 or more years ago I met this one old gentleman who used to be a professional clarinet player. He had jammed with Benny Goodman in the day when BG would come to town.
He had his clarinets in his basement that he hadn't touched for years. I tried to get him to play it just some with a soft reed etc. I ended up playing his personal fake book for him and he sang along and had a great time. It was fun for me too hearing his stories and such.
Plus he also taught me some better ear training and the important of a correct ligature.
A friend of mine (a musical one) has a father similarly situated. Pro for many years as a young engineer (just like his son), gradually got away from it but still kept his hand in on the side. Lived out in Oregon (out there in the misty Great Beyond), so I never saw much of him.
He sat in with us in a show pit about twelve years ago and was hell on wheels on both alto and clarinet, but he has gradually lost his abilities since then, and now does not play at all. And, as he didn't have many other interests, it's been somewhat limiting in his retirement. A sad state of affairs.
The older gentleman led me through a discovery of a high pitch squeal that I had with many clarinets, mouthpieces and reeds ... but the same ligature. After an hour I finally switched the ligature and the high pitched squeal was gone.
Now initially that squeal was not heard by me at all. Until he coaxed me to listen more to the higher pitches of the tone and then after about 10 minutes it become so apparent and bothersome!!
and that lead me to do research and experimentation on various ligature designs and how the "cradle" affected potential tonal qualities.
Of course this was, at best, semi-psuedo-scientific.
But ear training is just that. Learning to be more discerning on what you are hearing. Basically take the notion that you can improve on your ability and then strive various methods on improving upon it.
My ear training up to that point in college etc has been primarily intonation, articulation, initial attacks, dynamic interpretations, technique, you name it. but nothing in the notion of the "sound" itself, except in strings !!
For strings, as an example I was a good cello player. But in the basics you pull/push the bow across the strings between the bridge and finger board. If you get too far up, or too far down close to the bridge the tone suffers (and everything else), and (to me) it was very audible. To others it may not be as apparent. Also the type of strings being used varies greatly tonally, just research "gut" strings, as I was brought up on day one using gut strings (see this chat http://www.celloheaven.com/viewtopic.php?f=15&t=319 ) without really knowing anything except what i was being taught.
For a woodwind example, I used to be a Leblanc Player. Primarily my Noblet 45 and Leblanc LL. The tone was nice, woody you name it. But one thing always was lacking in a high degree and that was a tonal "ring" which the R13s are more famous for. (I initially thought it was the mpc) I found out the internal bore design of the R13 helped accomplish this. But initially I never understood that "ring" until i started really listening for it ... challenging myself to hear more than the basic "sound/tone".
Now add to that the concepts of playing a "C" but being able to change your tone to make it sweeter or rougher but still be a "C" takes understanding of being able to vary your tonal style and being able to hear it.
If you can't hear it, then it's all the same.
In essence, you have to challenge yourself to what you are hearing. If you change equipment, you have to challenge yourself to play to that equipment, such as the embouchure difference of using a short facing versus a long facing mouthpiece. If you use the same embouchure on a long facing mpc as you do on a short facing mpc you probably would clamp the reed down and make your long facing mpc a short faced mpc just from your embouchure.
Of course that led me on to blueprinting mouthpieces, clarinets, et all to understand why a mpc reacts, plays, etc the way it does in general.
Then on to the "resistance" inside a clarinet and how it relates to each tonehole design. This, to me, supports why people say the Selmer CT is the best jazz clarinet (though you can use it for any genre) and why a R13 is a "symphony" clarinet.
Loads of fun and always a learning experience.
I need to revisit those pages on my website one of these days as I may have learned more since then and make corrections/advancements.
I didn't even know there was a difference between a "modern" cello and a baroque cello until i searched for gut strings .. you never finish learning if you keep your eyes, ears and mind open. http://www.cello.org/heaven/baroque/baroque.htm