I am not familiar with the Marten Coltrane speakers, so I will not even try to make a comparison. The one thing I will add is the drivers used in kharma speakers are HEAVILY modified from stock form. Just for an example on the focal tweeters used kharma spends 4 hours on each tweeter- they take it apart remove the coating on the metal dome(I believe they use an acid of some sort to do this) and then put the tweeter back together with upgraded parts that they have found work well. They have similar proccess on all of there driver's, so don't be fooled just because they look like stock drivers.
