Double Ordering (meta_value_num and title)

You can do what you want using filters similar to those shown in this article: http://wordpress.mcdspot.com/2013/01/25/sort-on-presence-of-custom-field-field-value-then-date/

Thank you very much, but can you explain what exact code should I write in order to order posts by meta_value_num and title?

Okay I write

function mam_posts_orderby ($orderby) {
   global $mam_global_orderby;
   if ($mam_global_orderby) $orderby = $mam_global_orderby;
      return $orderby;
}
add_filter('posts_orderby','mam_posts_orderby');

in themes functions.php, but I think I done smth wrong in next code.
Code:

// Setup and run the query for getting the list of posts to show
	$args = array(
		'posts_per_page' => 500,
		'post_type' => 'product',
		'orderby' => 'meta_value_num title',
		'meta_key' => '_ss_views',
		'order' => 'DESC',
		'ignore_sticky_posts' => 1
	);
	// Add the filter here to get only those
	// within the setting of how far back
	// to check.
	add_filter( 'posts_where', 'within_set_limit' );
$mam_global_orderby = "$wpdb->postmeta.meta_value+0 DESC, $wpdb->posts.post_title ASC";

	$posts_in_range = new WP_Query( $args );

$mam_global_orderby = '';  // Clear the filter

Can you help me please?

Thanks, but it does not work.
I checked functions.php and find there this code for taxonomies

function my_post_queries( $query ) {
    // not an admin page and is the main query
    if ( !is_admin() && $query->is_main_query() ) {
        if ( is_category() || is_tax() ) {
            $query->set( 'orderby', 'meta_value_num' );
            $query->set( 'meta_key', '_ss_views' );
        }
    }
}
add_action( 'pre_get_posts', 'my_post_queries' );

Maybe adding some changes here may help?
P.s. i need order by meta_value_num (desc) and by title (asc) in categories.