The M chambers are theoretically a little darker than the D chamber and the S chamber is theoretically a little brighter than the D chamber. I say theoretically because the tone you get from a Dukoff is highly dependent on the baffle and they are quite inconsistent. In other words, you may find an S which is darker than the D you are familiar with. Similarly, you could find an M which is brighter. The Hollywood (H chamber) is a significant design departure from the D chamber, so definitely darker. The LD is darker, still.