It Really Works

At 1st was skeptical but wow it really works and well. I measured both ways using a single device and using 2 devices. It was right on Im really impressed.
However the instructions are not that clear. But not really hard to figure out.
I would suggest to the developer to put somewhere the distance limitation using 2 devices. For using a single device its just the distance from your earphones.

Gary Bryan about Acoustic Ruler Pro