i found his page but no list for the 400. also after reading his first paragraph i wonder how credible it is anyways. but either way the decay and frequency response it's the same as time relationship.
have you ever set up speakers in a room? it's very easy to have an unstable stereo image. reflections cause this to happen. When frequencies bounce off the wall and hit your ears at different times then it breaks up the image and personally causes the sound to hurt my ears. you have left and right. they need to hit at the same time and the less noise afterwards the better.