I'm recording pre-production home demos using pro tools with an Mbox2 and a RODE NT1a. For some reason when I record Trumpet (and even sax) the waveform recorded is very heavy to the left side. I've tried moving the mic to different places, playing into the mic at different angles, etc. and even tried other mics (Audio-Technica 3035, SM58s, etc) and everytime the waveform is heavy on one side or another.

Anyone have a suggestion to why this is occuring? I'm just a beginner in this stuff so any help is appreciated.

Cheers,
Greg