Boost center in audio output settings

Hello everyone.
First of all - best codek pack ever, thanks!
But I am interested in a small but very important detail - "Boost center" checkbox in audio output settings.

Why it is enabled by default?

What it changes so it was decided to turned ON by default?

When enabled it uses a mixing coefficient of 1.0 instead of 0.71 when mixing the center into the stereo channels. This effectively increase the volume of the sounds from the center with 3dB.

It is enabled by default because most people like it that way. When downmixing surround sound to stereo the volume of voices (which are in the Center channel) is often relatively low. This option improves that.