tax_query showing no results

I'm creating a music database site with two custom post types: tracks and albums. I've linked the tracks to their respective albums with a custom taxonomy for the album's slug. On each album page, I'm trying to get a tracklist of the album by retrieving all tracks with a dub_album_slug taxonomy that matches the slug of the current album. Here's my code for that query:

global $post;
$post_slug = $post-post_name;
$args = array (
    'post_type' = 'dub_track',
    'tax_query' = array(
        array(
            'taxonomy' = 'dub_album_slug',
            'field'    = 'name',
            'terms'    = $post_slug,
        ),
        'orderby' = 'dub_track_no',
        'order' = 'ASC',
    ),
);
$tracks_query = new WP_Query( $args );

At the moment, it doesn't output anything at all. Even if I manually put in a term that I know exists and has posts associated with it, nothing happens.

Here's the code I use to output the data:

?php if ($tracks_query-have_posts()) : ?
    ?php while ($tracks_query-have_posts()) : $tracks_query-the_post(); ?
        ?php echo get_the_term_list( $post-ID, 'dub_original_artist', '', ', ' ); ?
etc.

Here's my custom post type registration:

//Register Track Custom Post Type
if ( ! function_exists('dub_track_custom_post_type') ) {

    // Register Custom Post Type
    function dub_track_custom_post_type() {

        $labels = array(
            'name'                = _x( 'Tracks', 'Post Type General Name', 'text_domain' ),
            'singular_name'       = _x( 'Track', 'Post Type Singular Name', 'text_domain' ),
            //...
        );
        $rewrite = array(
            'slug'                = 'track',
            'with_front'          = true,
            'pages'               = true,
            'feeds'               = false,
        );
        $args = array(
            'label'               = __( 'dub_track', 'text_domain' ),
            'description'         = __( 'Dub Tracks', 'text_domain' ),
            'labels'              = $labels,
            'supports'            = array( 'title', 'editor', 'revisions', 'custom-fields', ),
            'taxonomies'          = array( 'track-no', 'original-artist', 'original-title', 'original-released', 'producer', 'comment', 'album-slug', 'artist', 'riddim' ),
            'hierarchical'        = false,
            'public'              = true,
            'show_ui'             = true,
            'show_in_menu'        = true,
            'show_in_nav_menus'   = true,
            'show_in_admin_bar'   = true,
            'menu_position'       = 5,
            'can_export'          = true,
            'has_archive'         = true,
            'exclude_from_search' = false,
            'publicly_queryable'  = true,
            'rewrite'             = $rewrite,
            'capability_type'     = 'post',
        );
        register_post_type( 'dub_track', $args );

    }

    // Hook into the 'init' action
    add_action( 'init', 'dub_track_custom_post_type', 0 );

}

Here's my custom taxonomy registration:

//Register Album Slug Custom Taxonomy
if ( ! function_exists( 'dub_album_slug' ) ) {

    // Register Custom Taxonomy
    function dub_album_slug() {

        $labels = array(
            'name'                       = _x( 'Album Slug', 'Taxonomy General Name', 'text_domain' ),
            'singular_name'              = _x( 'Album Slug', 'Taxonomy Singular Name', 'text_domain' ),
            //...
        );
        $rewrite = array(
            'slug'                       = 'album-slug',
            'with_front'                 = true,
            'hierarchical'               = false,
        );
        $args = array(
            'labels'                     = $labels,
            'hierarchical'               = false,
            'public'                     = true,
            'show_ui'                    = true,
            'show_admin_column'          = true,
            'show_in_nav_menus'          = true,
            'show_tagcloud'              = true,
            'rewrite'                    = $rewrite,
        );
        register_taxonomy( 'dub_album_slug', array( 'dub_track' ), $args );

    }

    // Hook into the 'init' action
    add_action( 'init', 'dub_album_slug', 0 );

}

Here's what I get from $tracks_query-request:

SELECT SQL_CALC_FOUND_ROWS dub_posts.ID FROM dub_posts INNER JOIN dub_term_relationships ON (dub_posts.ID = dub_term_relationships.object_id)
LEFT OUTER JOIN dub_term_relationships ON dub_posts.ID=dub_term_relationships.object_id
LEFT OUTER JOIN dub_term_taxonomy USING (term_taxonomy_id)
LEFT OUTER JOIN dub_terms USING (term_id) WHERE 1=1 AND ( dub_term_relationships.term_taxonomy_id IN (16) ) AND dub_posts.post_type = 'dub_track' AND (dub_posts.post_status = 'publish') AND (taxonomy = 'dub_track_no' OR taxonomy IS NULL) GROUP BY object_id ORDER BY GROUP_CONCAT(dub_terms.name ORDER BY name ASC) ASC LIMIT 0, 20

I'm not great with MySQL or how taxonomies work in the WordPress database.

I just thought of something that may be relevant. I'm using some code I found to order the tracks by the track number taxonomy. It modifies the MySQL query directly so I guess it could be causing a problem. Here it is:

function orderby_tax_clauses( $clauses, $wp_query ) {
global $wpdb;
$taxonomies = get_taxonomies();
foreach ($taxonomies as $taxonomy) {
    if ( isset( $wp_query-query['orderby'] )  $taxonomy == $wp_query-query['orderby'] ) {
        $clauses['join'] .=SQL
LEFT OUTER JOIN {$wpdb-term_relationships} ON {$wpdb-posts}.ID={$wpdb-term_relationships}.object_id
LEFT OUTER JOIN {$wpdb-term_taxonomy} USING (term_taxonomy_id)
LEFT OUTER JOIN {$wpdb-terms} USING (term_id)
SQL;
        $clauses['where'] .= " AND (taxonomy = '{$taxonomy}' OR taxonomy IS NULL)";
        $clauses['groupby'] = "object_id";
        $clauses['orderby'] = "GROUP_CONCAT({$wpdb-terms}.name ORDER BY name ASC) ";
        $clauses['orderby'] .= ( 'ASC' == strtoupper( $wp_query-get('order') ) ) ? 'ASC' : 'DESC';
    }
}
return $clauses;

}

add_filter('posts_clauses', 'orderby_tax_clauses', 10, 2 );

I hope you can help me out. Let me know if you need more code. Cheers