Using a Keystation 61 from M-Audio to create MIDI files for simulated Brass Ensemble.

I am trying to use my Keystation 61 keyboard from M-Audio to create MIDI files so that I can develop a Brass Ensemble that sounds real, as opposed to synthesized. When I try to record my notes for an instrument, such as a trumpet, I can hardly hear it on playback. It sounds muffled, whereas imported MIDIs sound great. What would cause this muffling of the sound. I do not have any drivers for the Keystation, but I don't think any are required (I could be wrong).

When I set up a track for Keystation it gives me a bunch of instruments, such a Tuba and Trumpet, but there are a lot of settings that I do not understand at all. Is there a way to learn the meanings of these settings, or is something else the real problem anyway? Thank you for your help !

I am using Logic Pro X, latest version, on OS X 10.10.5 on a four year old Mac Pro server.