I confess that I got my Aries and 12.7 arm at the same time and have not been motivated to audition it with and without for lack of a listening panel to help evaluate the difference. Just getting up and taking it in and out is enough to distort my memory. My firm conviction is that it is a considerable improvement, I did run the Aries for a little while without it at first. I thought it was an improvement then but I am not going to testify in court about it.