Overall I'm quite happy with what DEQ does to the frequency response (boosting bass and the high end); but I don't like what it does to the surround channel levels. I just made some measurements with different Dynamic EQ settings to confirm my impression that it boosts the surround channels too much.
(Please ignore the generally lumpy response - this isn't about that and I realised that my minidsp sub settings were messed up part way through).
For the centre and front channels the level of the mid frequencies remains fairly constant with different DEQ settings.
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But for the surround channels it also boosts the overall level...
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The situation is even worse when listening at lower levels...
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In the kHz range I think the level should stay roughly where the black line (DEQ off) is. With the DEQ set at 0dB offset it boosts the surrounds by at least 6dB, relative to the fronts.
I assume this is how it is intended to operate (and not an implementation error in my Denon AVC-X receiver). But for me, since I sit a lot closer to the surrounds than the front speakers the boosted surrounds are pretty obnoxious.
For quiet listening in the evening the surrounds are close to me and louder. If I set volume based on the surrounds the centre channel is too quiet - reducing dialogue intelligibility (a common problem). Alternatively if I set volume based on the centre channel I get blasted by loud music and effects from the surrounds, eg when the adverts come on.
Edit: Added poll