So briefly: 1) The Haas Effect, often referred to as the precedence effect, is the principle that the first arriving sound tells the ear where the sound is coming from. Your head takes all those reflections inside roughly 30 milliseconds and integrates them into the original. Even if the delayed sound is up to 10 dB louder, the ear will still integrate it into the original. Reflections after this time period are heard as echoes and within this time period they contribute to the timbre, add spaciousness and a sense of detail to the recorded material.
That brings me to my next point, 2) a loudspeaker's polar response. If all those early reflections are integrated into the original, shouldn't they be spectrally similar to the original? Sound waves are coming off a loudspeaker in all directions, bouncing off your walls and into your listening space. It certainly seems reasonable for sound reproduction. This may sound like I'm advocating an omnidirectional speaker, but it's not so simple. I would think in the right room and positioning, I'd bet that Mr. Linkwitz's Pluto would be an outstanding speaker. Anyone in the Bay area has one and would let me listen, Just write me! :D
OK, I'll move onto just one more quick point today. I personally want to hear what's on the recording--not some radical distortion of it that may sound good to me on certain songs or whatever and terrible on others, so a flat frequency response is pretty much a must and a smooth off axis set of responses has to be there as well due to Mr. Haas's discovery. If the recording is really bad, your going to need an EQ--you'll need one anyway as I'll discuss later beneath 300 Hz.
Well, that's it for today,