Power Response and Dispersion are back in fashion

[Aadams]

This is a quote from a JBL web site discussing speaker response measurement and actually uses the term "dispersion".  The JBL of old did not even publish performance parameters.

"Instead of focusing on a simple measurement such as on-axis frequency response, JBL measures systems in a field 360 degrees around the speaker and engineers the entire system to ensure off-axis response reflected to the mix position is also smooth and accurate. JBL defines the ultimate performance specification for new systems – what it will sound like in your room. At the mix position, you hear a combination of direct sound and sound reflected from the rooms surfaces. For sound arriving at the mix position to be smooth and neutral, it is not enough for a speaker to measure “flat” on-axis - it is essential the speaker have excellent off-axisperformance.  While other manufacturers use a single on-axis frequency response measurement taken at one point in space, JBL measures monitor systems over a sphere that encompasses all power radiated into the listening room – in every direction. This data reflects 1296 times the information of a single on-axis response curve. Seventy-two measurements of the direct sound field, the reflected sound field, and the reverberant field, the entire sound field heard by the listener, is correlated to optimize response at the listening position. In place of spectral smoothing used by some manufacturers, which actually conceals data, the JBL approach actually exposes flaws in systems, such as resonances, poor dispersion and other causes of off-axis coloration. The data shown below is a set of spatially measured graphs that are the heart of JBL’s philosophy. "

The new term is "Linear Spatial Reference" or LSR technology.