The speakers are the most important link in the sound and their placement in the room can significantly affect the sound quality. For better or worse.
In general, an equilateral triangle with respect to the speakers and the listener can be considered as a starting point. The speakers should be at listening level and aimed at the listening position.
The corner is not recommended because it tends to become distorted out loud. The proximity of the wall also affects the intensity of the upper bass. If possible, try how to adjust the speaker position to get the best results.