For a bash, focus on the bass
If this is a parents-out-of-town rager, you want everybody to know exactly what they should turn down for, that means a lot of bass, which means a lot of low frequencies. Low frequencies are “omnidirectional,” which means they come out in every direction no matter the bearing of the speaker. As a consequence, the best place for that speaker is going to be in a corner where the biggest fraction of those sound waves can be reflected into the room.
In fact, over 90% of the music you hear is the result of reflection. “It’s a lot like pool,” says Freeman, “Probably something like 10% of the energy that you hear comes at you directly from the speaker, and the rest is the sound that went out in all directions, bounced around a few times, and then hit you.” That’s why music in an empty room sounds terrible -- once you fill out that space with furniture, people, decorative piñatas, etc. the sound is dampened and starts to sound more full.
Get those speakers low
Low frequencies are also long wavelength frequencies, which means they don’t interact as much with low-profile objects like people in the same way that shorter wavelength frequencies will. As a consequence, you should leave your speaker closer to the floor in a corner, because it’s going to saturate omni directionally. The combination of the floor and the two walls will cause the sound to be more directed. Just be aware that there tends to be a lot of variation in bass frequency depending on your position in the room; as you move from the middle of the room to the walls, the bass will go from a thinner sound to a deeper one. That means wallflowers are having a bad party experience for multiple reasons.