As of WP Voting Contest version 3.3.6, the core Voting System now supports MP3 uploads. In order for the MP3 to have a cover like our demo, enable the image upload field and make sure to have your contest type set to MUSIC. You must also set Enable Music Upload to YES.
If your contestants will be embedding their music from websites like reverbnation.com or soundcloud.com, you should select ESSAY as the contest type because it is better suited to submit embed code from your contestants using the description field. This way our built in player will not conflict with the embedded one.