As mentioned above, the equalization is a featire that helps to correct the sound quality for your particular room. The system measures how your room affects the sound and compensates for it. It has nothing to do with the loudness of explosions.
Onkyo and Denon use a EQ system called Audyssey MultEQ XT(http://www.audyssey.com/audio-technology/multeq
) which was developed by Audyssey originally as an add-on device (costing $2K), but now is built into many inexpensive receivers.
Pioneer uses a EQ system they call MCACC
, which is a Pioneer specific feature. It has the same overall effect but works differently. Some people prefer one over the other. I prefer Audyssey because it provides a high degree of correction for the subwoofer channel which is usually the most problematic issue for many people's rooms. Pioneer's system does no correction which is a big omission IMO.
For the issues of explosions being too loud:
What you want is a dynamic range compression feature. In earlier receivers, this used to be called "night mode" or something like that. It was a very simple circuit which compressed the sound.
But now both Denon and Onkyo provide a feature called Audyssey Dynamic Volume
which analyzes the sound in real time and provides consistent volume control (http://www.audyssey.com/audio-technology/dynamic-volume
The Onkyo goes a step further in offering Dolby Volume
which is Dolby Corp's similar technology. http://www.dolby.com/us/en/consumer/...-details.html#
which is available in the THX mode of the receiver. If you are not in THX mode, you can use Audyssey Dynamic Volume (you can choose either in the settings)
Pioneer doesn't offer either but has a ALC mode which provides the same overall effect.
All three receivers (709/1121/2112) also offer low volume compensation. On the Denon, it's called Audyssey Dynamic EQ
). On the Pioneer, you can use THX Loudness Plus
in the THX mode. The Onkyo has both Dynamic EQ and THX Loudness Plus. This is a great feature because if you listen at lower volumes, it helps improve the sound. I upgraded my perfectly fine receiver just to get this feature, because I find it makes a very noticable difference and improves my enjoyment of the sound.
As for the Elite vs Pioneer, the Elite series is mainly sold at audio/video dealers whereas the regular Pioneer is mostly mainstream retailers. There is overlap between the two lines. I guess the most important difference is the longer warranty on the Elite (2 vs 1 year)