I've going over my collection, filling in any items I'm missing, I felt I really should have a modernized version of the Sigma. I came across a rather abused normal bias set which needed new drivers but wanted to try something different... so here is the SR-Sigma 507:
The housing was very discolored so I wanted to try my hand at painting it. The frame was primed and painted satin black but I left all of the other parts in the primer color. The plan was to make them gloss white but this looked too cool so this is how they stayed.
The drivers and cable are from a 507 so it took a lot of work to get this right. The drivers are in the cage that Stax introduced with the x07 series so I glued the drivers and fitted spare metal grills to them.
In terms of sound, this is the best Sigma I've ever heard. The bass is overblown, as is always the case with Sigma's, but it has some real power to it and is more controlled than every other I've heard. The top end is nice and clean and the midrange is just sublime. A fun addition to the collection.