Been playing Tenor Sax for a number of years, and just taken up Clarinet instead.
So... when I check the tuning from cold it is always spot on.
The Sax used to go sharp as it warmed up.
As there is no way of making the clarinet shorter I hope it doesn't go flat.
My playing is pretty basic - it's a very different instrument - so trying to check the tuning when warm is not very precise.
When the clarinet cold and not warmed up, it has a flat tendency. As you get warmer it will become sharper and more in tune. There is a way to adjust you tuning...if you are flat then make sure that all the joints are completely pushed together and tight. Likewise, if you are sharp, then you can pull the barrel out from the top joint a little bit ( a centimeter or so) and that will temporarily help your tuning until you are warm
in general temperature tends to affect pitch similarly on most instruments, going flat when cold and sharper when warm. i think it has something to do with the air itself, and the sound waves? (not positive, someone else might know more about this)
i actually wanted to do a science fair project about that a couple years back, but i couldnt because there was no way to take the human element out entirely. (our science fair rules are strict. all sorts of crazy stuff counts as "human subject")
It is the same as a sax. Once it is warmed up, it goes sharp. Sometimes really sharp and makes your ears curl! When it is cold it is flat. Sometimes the tone of the clarinet is aweful when it is flat. It has a buzzzzzzzzy tone when it is flat. The sharper it the clarinet is the higher the pitch it is than normal. Like playing a A will sound like a A#. Have a tuner and learn to tune and sooner or later you will know how to set up your instrument perfectly in tune.
At the start, make sure everything is together tightly so it will sound a little better. After a 2 page song, pull either the bell or barrel to the right legenth of the instument. Play your Concert Bb. You should be able to tell if it is sharp or flat after a month or two of play. Since I have been playing for over a long time, I can tell if my clarient is flat, sharp or in perfectly in tune.
I hope you are liking the clarinet because it is a beautiful toned instrument. It is easy to play but having the perfect tone is a challege!!