Better to remove the speakers altogether - you get two effects from the presence of another speaker. One is the drivers will act as passive radiators to one degree or another - depends on the size and proximity as well as the volume of the driver cavity. The other effect is from the enclosure - think of a Helmholtz resonator. This can especially affect the bass depending on your speaker design (ported, folded line, etc.).
There are of course lots of variables to the degree and type of effects - speaker design, proximity, and room placement to name the main ones.