I wanted to share what Richard Vandersteen thinks about sweet spot. This is a direct quote:
Most speakers today especially those with narrow baffles have a wide dispersion pattern and therefore will have a decent stereo image off axis. Having noted this if there is only a small improvement when sitting in the “sweet spot” this is a sure indication of low resolution as imaging is created by small differences in time, phase, amplitude and differential time between left and right channels. Most of these ingredients are at least compromised when the listener is not equal distance from the two speakers. Evidence of high resolution, time, phase accuracy and reasonable acoustic symmetry within the room is a significant improvement of all things coveted by most audio enthusiasts when seated in the “sweet spot”. The only way to make the “sweet spot” larger is to lower resolution and homogenize the signals enough to make the presentation mediocre everywhere. RV
Most speakers today especially those with narrow baffles have a wide dispersion pattern and therefore will have a decent stereo image off axis. Having noted this if there is only a small improvement when sitting in the “sweet spot” this is a sure indication of low resolution as imaging is created by small differences in time, phase, amplitude and differential time between left and right channels. Most of these ingredients are at least compromised when the listener is not equal distance from the two speakers. Evidence of high resolution, time, phase accuracy and reasonable acoustic symmetry within the room is a significant improvement of all things coveted by most audio enthusiasts when seated in the “sweet spot”. The only way to make the “sweet spot” larger is to lower resolution and homogenize the signals enough to make the presentation mediocre everywhere. RV