Getting your speaker geometry correct is easy with the right tools
By Phil O'Keefe
Many of you will already be familiar with the common recommendation of setting up your near field monitors in an equilateral triangle arrangement. In such a setup, the monitors are placed the same distance from each other (typically, 3-4 feet) as they are from your listening position, so that the two speakers and the listener's head sit at the three points of an equilateral triangle. This is relatively easy to achieve with little more than a tape measure, or a few feet of string. But what about toe-in?
Toe-in, or angling the speakers inwards towards the listening position so that the listener is more on-axis with the speakers, is another often-recommended monitor setup technique, but it can be a little tricky making sure the two monitors are angled exactly the same way. You can use a protractor, but most are too small to easily get the angles of each speaker matched up more accurately than "fairly close", and if you have a surround speaker setup, things become even more complicated.
MODERN TOOLS TO THE RESCUE
Do you have an iOS device (iPhone 4 / iPad 2, or later), or an Android device containing a gyroscope sensor, such as a Nexus or Galaxy tablet, HTC Evo 3 or 4, or Galaxy II or III? If you do, check out Genelec's handy SpeakerAngle app. (Fig 1) This very affordable ($0.99 USD) app simplifies the task of setting up and matching your speaker angles to such a degree (pardon the pun), I now consider it a must-have for anyone interested in recording - or for that matter, anyone who is interested in listening to music played back over speakers, or who wants to optimize their home theater's surround sound speaker setup.
Figure 1: Genelec's SpeakerAngle app
Using the application for stereo monitor setups is super easy. Set your speakers up an equal distance from the centerline of your room, and face each one directly forward. You can use the front surface of the desk, meter bridge, or whatever you have the speakers sitting on as a point of reference. Then set your smartphone or tablet on top of one of the speakers, and "zero" the app. Then tap on the icon for the speaker you want to adjust first, and then as you adjust the physical speaker's toe-in angle, the in-app icon for the speaker you're positioning changes angle, and the app also displays the number of degrees of actual angle for the speaker. There is also a color indicator that changes from red (0-19 degrees) to dark green (20-26 degrees) and bright green (27-33 degrees), then back to dark green (34-45 degrees) and finally back to red (46 degree angle or greater) to give you an idea of the acceptable, and optimal angles, with the angles in the "bright green" range (30 degrees, +/- 3 degrees) being generally considered as the best in most situations.
The SpeakerAngle application has both stereo as well as surround sound modes. (Fig 2)
Figure 2: SpeakerAngle supports surround sound systems up to 7.1
For home theater owners and those who are lucky enough to have studios with surround sound monitoring, SpeakerAngle can be used to configure 5.1 and 7.1 surround sound setups. The basic steps involved in configuring a surround sound system are similar to the ones used in stereo mode.
The application's own in-app instructions are clear and complete, but it really is a simple program, and many users will probably be able to figure it out without ever having to refer to the instructions. Still, the instructions are full of useful information to help you with the process of getting your speakers set up optimally, so I'd recommend having at least a quick glance at them. But even if you never check them out, do check out this app. If you use speakers, it makes the process of setting them up correctly a lot easier. iOS device users can purchase Genelec's SpeakerAngle app through the Apple iTunes store, and Android users can purchase it through Google Play.