In live sound it is common to have a left/right sub-speaker configuration, which will produce an strong interference pattern in the audience area based on listener/sub-speaker locations.
If the left/right sub-speakers were decorrelated (phase randomization?) would this help reduce the interference pattern in the audience area? Would the effect be minimal or significant at low frequencies?
You will simply change the interference pattern. By modifying the phase at different frequencies you will simply change the phase relationship between the two speakers and thus move the locations of any pressure nulls/nodes at that frequency. It would be pure luck as to whether this would 'reduce' the interference pattern; also depending on your definition of the reduce in this context.
With a single loudspeaker you can generally control the sound pressure at one location. Two speakers would give you control at two discrete points. N speakers, at N points. In a reverberant environment you will also need to identify the room response as well to achieve this.
The above rule can be broken, by using some kind of optimisation (least-squares as probably the simplest) to optimise the freqeuency response at N control locations toward a certain target (flat frequency response?), using M speakers, where M < N. You wouldn't get very far with 2 speakers though.
Read up on sound zones for some interesting background material on this and some rather extreme speaker configurations :)
You are moving a fairly advanced topic here. I'm not an acoustics expert, but I can clearly see how the room layout (i.e. are there just walls or lots of furniture, curtains etc.) would affect the answer here. The frequency of the sound, position of the listener and distance/orientation of the speakers are not without meaning here. Based on this data, you could come up with some specific solution that'd reduce the interference locally, but simple phase decorelation will only make it sound strange (i.e. if you simply reverse the polarity of one speaker and leave one unchanged or digitally shift the phase by fixed number of deg)
