My minimum phase version is straight line, why?

[Quickmcj]

Hi all

When following the OCA guide on youtube "Convolution with Inversion", when I get to the step to create minimum phase versions of the inverted responses, the tweeter minimum phase version looks fine, but any other driver used, will result in a "straight line" as response. Please see photos of working tweeter minimum phase (purple), and erroneous midrange minimum phase version (green). Can anybody explain this?

 

[Quickmcj]

Ok I think I found that is has something to do with the regularisation settings, when creating the inverted response, before you then create the minimum phase version. By adjusting regularisation (1-2%) I can get good looking measurements. I will leave the post as if anybody else encounters this.