JBL's SpeakerAngle app (downloadable for free) scientifically measures and allows for the precise alignment of "toe-in" of the left and right monitors as aimed at the center listening position. Any differences in speaker distances and toe-in angles can cause subtle inaccuracies in stereo imaging and detail. SpeakerAngle uses the iOS device's internal gyroscope to measure the toe-in angle of one speaker for adjusting and matching it to the other speaker's angle.

After placing my iPad on top of the left monitor (monitors that are not flat on top will require you to hold the iOS device steady while aimed to the front) and aligning the front of the speaker straight on (no angle). I then carefully turned the iPad and monitor speaker so that the tweeter pointed at the left ear of my helper sitting in a chair at the listening position.

When the angle indicator window should change to a value of over 20 degrees (to a maximum of 45-degrees) at which point the window changes to a green background. Touching the icon a second time stores and freezes that heading. I repeated the process for the right monitor and when I achieved a matching angle, the right speaker icon changed to yellow, verifying the same toe-in angle.

The JBL SpeakerPro app ($1.99 download) is an advanced version of SpeakerAngle that makes intelligent speaker angling recommendations based on your speakers system's distance measurements--even if your speakers are not set up in an equilateral triangle.

It connects to your monitor speakers (or audio system) using a cable (not included) that splits the stereo output signal of the iOS device into separate left and right cables fitted with either RCA, 1/4-inch or XLR connectors. I made my own and there are complete details in the step-by-step instruction manual included with the download or you could buy one at your local stereo/electronics store.

SpeakerPro produces sonic impulses--"clicks" that are picked up by the iOS device's microphone. After calibration to compensate for the latency of your audio system, JBL SpeakerPro uses a patented version of the "time-of-flight" technology to measure precisely the distance between the left and right speakers and the distance of each of those speakers to the listening position within fractions of an inch.

JBL SpeakerAngle and JBL SpeakerPro are necessary tools for home project studio or home theatre owners and are now available for download from the Apple App Store.

SpeakerAngle is free of charge while SpeakerPro is available for $1.99.