If you mean, it sounds like the bass is more prominent from the left side, then the placement of the sub isnt ideal.
A good way to find a starting point for sub placement is to sit it in the listening position with the port if it has one, if not the sub at around ear level port firing towards the full range if front ported, or away if rear ported.
Then crawl around the floor till it sounds good in a certain spot, position the sub here and experiment further.
Questions is the sub ported? If so port location? Also what way does the sub fire? down, forward etc.