Pritam, welcome. You should separate the left and right speakers, if possible, by at least the same amount as your distance from them. For example, if you're sitting about 10' from the speakers, they should also be separated by 10' or a bit more. With speakers such as your Axioms which have very wide dispersion there's no need to worry about a wide separation causing a "hole in the middle", especially if you toe the speakers in slightly so that the tweeters point at your ears.

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Enjoy the music, not the equipment.