Years ago, we learned as students that the A clarinet was quite difficult to play, and we were advised to get an A that was less resistant than the Bb. The idea of a “matched set” is just a euphemism in my memory, and while I do have a set of Model 55 Selmer clarinets with serial numbers within four digits of one another, I would call them matched in no sense of the word, for they are not.
In theory then, if the teaching I received was correct, an A that plays with less resistance is ideal, but then again, when we wanted to really sound well on the Bb, we practiced on the A, exclusively, for the Bb was quite simple to play after the A.
Even further backward in time, the two clarinets were or are to be played with different mouthpieces, and even further back , the attachment could be bought which, when lowered into the Bb made it almost an A. That was actually the thick string which made the horn terrible stuffy and plain “out of tune”, probably resulting in the thought that the A was more difficult than the Bb.
And looking even further back, when first I played the classical three-keyed clarinetr in boxwood, I then had made another joint to replace the lower of the Bb to make it into an A. That seemed to work quite well.
The A clarinets of the last 10 or 15 years or so are equal to the Bb, and sometimes they are better. My current A clarinet seems to almost play itself and all the resistance and intonation worries are quite resolved. Thanks to Tom Ridenour for that. His hard rubber A is the best I have ever played.
If you have a good A clarinet, playing those first notes in the slow movement of the Brahms 4th symphony is quite close to heaven. You seem to be able to hear that middle B as if you were in the back of the hall at the same time. Ah, memories.