I have a Marshall 1960B. It has the four 75W Celestians and is rated at 300W, I think, as I have not used it or looked at it in years because a friend has it in his studio . But now my friend needs the space and so I am going to pick it up. You can run it in mono or stereo. Here is the mod that I would like to do and would like some feedback on. It is my intention to use this in stereo and connect each of my two Tremoverbs to it, one on each side respectively. In and effort to get a tighter and better sound (maybe some punchier low end), I thought of isolating the left and right side from each other. My question is this. If I used 3/4" plywood to insert (permanently affixed of course) between the speaker sets on the left and right side of the cabinet would this yield a good sound. This would be like having two vertical 2x12s in one speaker enclosure. I would not change anything about the cabinet. I would just add this separator to isolate each side of the cabinet and then acoustically seal each side. I guess I would use a very small amount of sealant in all the seams and then add some insulation to each side. This would then be two side by side vertical 2x12s. But, would this sound good? Please help and don't be afraid to tell me what you really think this will achieve. I am not a speaker engineer and would really appreciate your help, thanks.