I think that there are at least two reasons that go into including any feature in some equipment, the first is actual benefit, the second is marketing. I think marketing is the larger reason by a factor of 3 or 4 to 1. Whether or not a feature is actually beneficial is irrelevant: if consumers think some feature is a real benefit then when comparing brand A with the feature to brand B without it, the majority of consumers will pick brand A. This being the case, what company wants to be brand B is this scenario? Therefore, within six months of a company including some readily copied feature X in their mass-market models, most other companies will have their own version of feature X in their latest models. The fact that several manufacturers are including simplistic EQ in their receivers lends no real support to the dubious benefits of such a feature.

If you want room EQ to be generally beneficial in your room, you’ll need to sample about two dozen points within the listening areas of the room, toss out any oddball anomalies from the results and average the rest. After this make moderate adjustments.

A practical demonstration of why I think single-point sampling is nearly worthless:

If your computer is connected to your sound system, or can be, download a free sine wave generator. If your system-to-subwoofer crossover point is 80Hz, generate a tone of about 60Hz and play it back at a moderate volume. If you have an SPL meter, walk slowly from place to place in your room watching the readings. In my room with a steady tone I see at least a 10db swing from highest to lowest reading. Now do the same with 50Hz. Were the peaks and valleys in the same places as with 60Hz? Try again with 40Hz. After this series, try one for your other speakers by generating 120Hz and above. Even if you don’t have an SPL meter, you can plug one ear and move the other ear slowly about the room moving both horizontally and vertically. Likely you will find spots where a particular tone grows louder and other spots where the tone seems to disappear altogether.

Someone is going to say, “But the EQ systems don’t use sustained sine waves for testing.” That’s right. But consider this: every complex wave can be reduced to the sum of multiple changing sine waves. And this: musical notes are generally held long enough for some of their frequency components to establish standing waves in your room, at least momentarily. As a result, I consider the sustained sine wave example above a valid one as far as a worst-case scenario in order to point out the foibles of single-point EQ setups.