My understanding is that the sub has to be set slightly behind the main speakers. I place mine beside the right speaker 6 inches or so back. Integrates very well. Centred between the 2 would be even better.
If you are having issues, it's likely the room or the sub itself - or the sub setting, many people volume the sub too high thinking it will give 'more' bass but instead it muddies everything.
If you are having issues, it's likely the room or the sub itself - or the sub setting, many people volume the sub too high thinking it will give 'more' bass but instead it muddies everything.