Open plugins/content/commedia/commedia.php file and find there:
if ($showDet)
$html.='<div class="mp3det"'.(($showPop<2)?' style="width: '.$playWidth.'px;"':'').'><a href="'.$link.'" target="_self">'.JTEXT::_('COMMEDIA_DETAILES').'</a></div>';
replace it to
if ($showDet)
$html.='<div class="mp3det"'.(($showPop<2)?' style="width: '.$playWidth.'px;"':'').'><a href="'.$link.'" target="_blank">'.JTEXT::_('COMMEDIA_DETAILES').'</a></div>';
Also replace:
$_name = '<div class="commname '.(($showName == 2)?'commcenter':'commleft').'" '.($showDet?'on-click="window.open(\''.$link.'\',\'_self\')" style="cursor: pointer;"':'').'>';
to
$_name = '<div class="commname '.(($showName == 2)?'commcenter':'commleft').'" '.($showDet?'on-click="window.open(\''.$link.'\',\'_blank\')" style="cursor: pointer;"':'').'>';
So You need replace
_self option to
_blank in Your code.