well red it's hard to say without hearing it. if you are out on all the notes, it's probabaly you, not the horn. and why can't it be just pushing the mpc in or out? another thing did the band actually tune up? i know some guy can't tune their own gitars by themselves let alone with others they are playing with. so there are lots of variables involved. i played with some garage bands where i had to play the same song in different keys cause the morons couldn't stay in tune. also could you not hear what you were playing? it helps to have a monitor or play near the pa system if you are mic into it along with the vocals.

All of you need to tune to the keyboards. Digital synths have a pitch variance in different patches. An analog lead line synth has no set tuning. They are hard to keep in tune. I would suggest that everybody should tune to a piano patch on the digital or analog polyphonic synth. As the heat goes up, your sax will go sharp and the guitars flat. Someone needs to be in the audience to tell you how it sounds. In a hot room you are going to pull your mouthpiece out. I have encountered these problems before as a sax and keyboaerd player. The bottom line is to practice with the full band and hammer it out!!!! If the keyboardist tunes to a chromatic tuner, that would be the ultimate effeciency approach. Best of luck to you :)