Two weeks ago I took the plunge to add Brian's TRT caps to my RM-40's. While doing so it was obvious that this was the perfect time to make the slight modification necessary to go from passive to active biamplification (shorting out one coil). Brian had told me that adding the caps was "quite a job" but that the improvement "though not earth shattering will be noticable". Boy, did I ever get lied to!!! Firstly, adding the TRT's was a piece of cake. The hardest thing really was getting the old caps loose from the circut board. I did the first speaker in about three hours from start to finish, and I am not much of a do it yourselfer either. The second speaker, now that I knew what I was doing, only took a little over two hours. At age 70+ if I can do this by myself, anyone can! As to Bryan's comment that the difference would be noticable -- I am absollutely astounded. There is at least a 50% improvement in sound! Active biamplification has the advantage of reducing inetrmodulation distortion (in theory). However I found the improvements with the Marchand crossover that Brian recommend , although noticable to be slight. Brian maybe its just that you have designed the RM-40 so well that any such distortion is not noticable. All in all, this was a very easy change to make, worth the time and expense many times over. Next project -- the FST tweeter.
