The album was mixed by a Canadian engineer, Phil Anderson, and mastered by Maor Appelbaum, who has worked with a lot of great artists such as Faith No More, Yes and Yngwie Malmsteen to name a few. Phil and Maor have a perfect combination and they have worked together on many projects. Thanks to them, "Heir to Despair" turned out the heaviest Sigh album.
http://www.metalunderground.com/news/details.cfm?newsid=141873
Philsmix and Solid State Logic