function disable_admin_bar_for_subscribers(){
    if ( is_user_logged_in() ):
        global $current_user;
        if( !empty( $current_user->caps[\'subscriber\'] ) ):
            add_filter(\'show_admin_bar\', \'__return_false\');
        endif;
    endif;
}
add_action(\'init\', \'disable_admin_bar_for_subscribers\', 9);