Looking for a fast and easy way to ensure that your studio monitors are aligned at the proper angle for critical listening? You could try eyeballing them. You could break out the protractor. But an easier solution is to purchase Genelec’s SpeakerAngle app (less than a buck at the iTunes store).
With SpeakerAngle running on your iPad, setting your monitors to the proper angle is as easy as setting the iPad on top of each speaker, then turning the speaker. SpeakerAngle tells you when you are lined up for best listening. Works for both stereo and surround sound setups.