Is an eight sided oval room acoustically correct?

Haven't seen those. I have seen some descent pruning sheers at home depot though:)

If the cuts are minimum it's a good idea. It will relieve the corner pressure. However, if they get too large it begines to create some pretty interesting interactions that are not easy to describe, but suffice to say that more than about 15% of the length of wall cut as you propose and you may encounter some problems. As to the "dome", well, I don't like to disagree, but about the only worse scenario would be a round room. The dome will focus energy in one place. If you go to our listening room you can see what a bay window can do to the sound field. A dome compounds the problem. It can create a "neat" effect, but is not advised for a dedicated listening space.

Maxgain: I do have experience with these types of products. What they do is reduce the resonance in the glass. This may be a problem for you (it depends on the glass insert), but it's not the problem we discuss regarding bay windows on our website. These materials will do nothing for "focus effect" problem that bay windows have.

Maxgain: The tube traps will help. The other option would be to use heavy drapes but just close them enough so that the angled portions of the window are hidden from view. Then the plant does help with diffusion and you've minimized if not eliminated the bay window focussing issue. The drapes would probably look nicer than the tube traps and might get siginificantly better spousal approval ratings.

The Hat Rack: I'm here at CES and it's on display at a few places. There are many things in this audio world that make large differences that you wouldn't expect to. So far everything I have ever heard that made a difference has some sort of physical reason that it made a change--sometimes not for the better. As a physicist, I can't find any physical reason how the hat rack would have any effect on the sound (unless it's placed in front of the speakers). There's virtually no band width by it's design and thus it can't effect the sound waves. I would really like to read some scientific explaination (or anything even plausible) on how this can effect the sound waves.

Okay after my post I made it a point that day to listen to the "hat rack". I think it's really called something like the hologram something or other, but it looks like a hat rack--so I like Hat Rack better. In a room with absolutely bare corners and a very high resolution system, I could hear a difference with it in and out. It broke up a very small band of frequencies in the lower mid band enough to add a little clarity in that range. However, I think it's only useful in a room that has little or no diffusion. There are much better ways of accomplishing more for far less money. For example, in a bare room take one panel of slatted shutter doors and put one in each corner--compare that to the hat rack--it will make a huge difference (not always for the better mind you). I think that's one of the issues with some tweaks--make them benign enough that they don't do harm. I doubt seriously the hat rack will ever cause any problems in a room--but it's not going to fix too much either.