An ombisher is the muscle that controls your lip movement. In other words your kissing muscle. You'll have to know how to control this when playing an woodwind or brass instrument.
First of all, I think the word is spelled 'embrochure.' But then again, I've never been a good speller. Now, pretend you're blowing over the top of a bottle. I know it's hard, but don't give up. It just takes a bit of practice to find the sweet spot, but once you get it down, you'll have it for life.
First be find out if you are about the same amount flat on an open pitch like second line G and a closed pitch like third line C. Try several notes at the top of the clarinet (open fingerings) and several at the bottom closed fingerings). If the top, open notes are noticeably flatter than the bottom, closed notes, you could benefit from a shorter tuning barrel. If that's not the case, and it probably isn't, then you probably have some work to to do on your embouchure, especially if you haven't been playing long. Building strength in your embouchure will raise your pitch a bit. One final possibility - only if you are a solid, experienced player - is to try some different mouthpieces.
First of all, I think the word is spelled 'embrochure.' But then again, I've never been a good speller. Now, pretend you're blowing over the top of a bottle. I know it's hard, but don't give up. It just takes a bit of practice to find the sweet spot, but once you get it down, you'll have it for life.
First be find out if you are about the same amount flat on an open pitch like second line G and a closed pitch like third line C. Try several notes at the top of the clarinet (open fingerings) and several at the bottom closed fingerings). If the top, open notes are noticeably flatter than the bottom, closed notes, you could benefit from a shorter tuning barrel. If that's not the case, and it probably isn't, then you probably have some work to to do on your embouchure, especially if you haven't been playing long. Building strength in your embouchure will raise your pitch a bit. One final possibility - only if you are a solid, experienced player - is to try some different mouthpieces.