I'm guessing your new to logic, no offense. It's quite easy to get lost in a new DAW, especially LOGIC. I would suggest that you read the recording portion of your manual. It's how I figured it out. Or even better, watch sfxninja's videos on youtube. just type in logic tutorial videos and it should pop it.
Anyhow,
You should be able to hear it in Audio channels. I will try to explain the best I can because I have the 2000xl hooked up to my audio Interface through the audio input. Since you are seeing results in your midi instrument you know that its communicating properly through your soundcard. So what you need to do is this.
In the Mixer. Go to logic audio track 1. Go down to where it says input 1 or input 2. and change these until you see audio coming in. but DON"T forget to press the Record button once until it is blinking. Or else you wont hear or see any input in the audio tracks mixer.
If you are not hearing sound STILL, make sure you set up your audio interface correctly on your mac during your installation. You might have luck on their boards if you get this far and get stuck. It'd be a good idea to browse their manual also.
Best of luck, but I wouldn't stop short of making sure you are seeing that audio signal coming into audio track 1. if you get this figured out I'll help you out with using Logic as a master to make the mpc play along when you hit play ect.
Good luck.
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