When I load an MP3 file and play it I do not have any sound. I suppose that Magic Studio do not use the correct sound card but I do not find where I can modify this paremeter to use the correct sound card.
This the 'Vegas Pro' audio group forum. I am not aware of a "Magic Studio" application? .
That said and assuming you see playback activity in the master output meter, check your Audio Device type settings. In VP, it is in "Options> Preferences> Audio Devices".
'MS Sound Mapper' or the 'Classic Wave Driver' usually work without issue.