The EARS and EARS RT auralization procedure usually starts with a reflectogram generated by EASE or AURA although impulse files generated by most popular measurement programs can be imported into the programs and used instead.

EASE uses Ray Tracing techniques to capture all the sound impacts, both direct and reflected, that arrive at a specified point within the room (in EASE terminology a Listeners Seat). It records the arrival time, the magnitude, and the arrival direction of each ray that hits the Listeners Seat over a specified period of time.

The information gathered during the ray tracing impact study is then converted into and displayed as a Reflectogram showing the magnitude of each impact as well as its arrival time. In the Reflectogram shown left, the red lines represent direct sound and the green lines reflections.

The computation times for Impact studies can be quite long, especially for complex rooms and ones having a number of loudspeakers. As a result, most impact studies are limited to 350 to 450 msec even though this is far less than most room’s reverberation times. In the Reflectogram shown above, the study was limited to 400 msec even though the room’s reverberation time is over 1 second.

Fortunately, in most rooms the reverberations take on a statistical behavior after 180 to 250 msec have elapsed. This allows a statistical tail to be added to the Reflectogram to fill out the remaining time. Details on this procedure are covered in Step 2, Adding a Statistical Tail.

The data gathered can also be displayed as a "Waterfall" showing each rays arrival time and its magnitude across the entire 7-octave frequency band covered by EASE. Notice how the amplitude varies with frequency.

The data can also be viewed as a "Hedgehog" display showing both relative magnitude and arrival angles.

EARS and EARS RT utilize all of this information to generate auralizations that truly reflect the overall frequency response, relative levels and directivity.