Your trusty RadioShack meter only measures SPL of the test signal coming from a speaker. Usually the signal is some variation of white noise or other generic tone that includes many different frequencies of the sound. The 10 band EQ will allow you to adjust the relative level of 10 individual bands of frequencies sort of like a very sophisticated tone control. Thus you could boost the midrange and decrease the high end if you so choose. This will allow you to customize the sound in your room to your specific tastes. Note that this is quite a bit like a manual version of the Digital Signal Processing you find in many processors (Arena, Lounge, Theater, Stadium, Opera and many more) although many of those also add some amount of reverberation to get the desired effect. The setup should be similar to what you do now where you measure the distance and adjust the SPL of each channel to be the same at you listening position. After that is complete is when I think you would employ the Equalizer to adjust the sound to your preference. The EQ will basically allow you to attenuate or boost the individual frequencies to your room and tastes. Depending on how much adjustment is allowed by the EQ this can give you an incredible amount of control over the sound. Most companies don't include it as an option because most of us want the output of our systems to mirror what is recorded as closely as possible. For the folks that like to tweek their systems and play with the room a lot the Equalizer will be a joy. Bear in mind Equalizers are available aftermarket.