adjust power output

[Sorensen]

…  it`s just that i have heard a few reports regarding Devialet sound a little closed in at low volume.

I think 2 things are going on at low volume.

First, as @Jean-Marie said, there's the way our ears work at low volumes. We're less sensitive to both high and low frequencies at low volume so the perceived volume of the highs and lows decreases as you decrease the volume and the amount our perception of level decreases also increases as the frequency gets lower in the bass and higher in the highs. In effect the volume control acts like a tone control and turning the volume down decreases our perception of bass and high frequencies, turning it up increases our perception of those frequencies, more than it affects our perception of the mids. Music can start to sound "flat" or "dull" at low volumes because we're no longer hearing the level of bass and highs that are appropriate to the tonal balance of the music.

Second, a doubling or halving of the volume is in itself less noticeable at low volumes than it is at high volumes. To double or halve our perception of the volume requires an increase or decrease in level of around 7 to 10 dB. You say you normally listen at around -30 to - 40 dB volume settings. Try increasing the volume from -40 dBm say, on some music, to somewhere around -33 to -30 dB and notice how much louder it sounds to you. Then try increasing it again by the same amount so now the volume setting will be somewhere between -26 and -20 dB and notice how that second increase seems to make a much bigger effect on what you're hearing in a lot of ways, not only in an increase in volume but also the increase in the bass and high frequencies and in other things like the dynamic impact of level increases in the music itself as the musicians attack a louder passage. Another change is that the soundstage will seem to swell in size a lot more during louder passages.

Changes in volume affect more than just the loudness of the music, they affect a number of other things that are important to the "character" of the music in various ways. You "turn a lot of things down" when you lower the volume. I'm not suggesting that you should listen at a louder level, listen at whatever level you like provided you enjoy what you're hearing and you're not damaging your hearing. What I am saying is that comments about things sounding a little closed in at low volume are usually being made by people who listen at higher volumes and are heavily influenced by the changes they hear as they lower the volume. If you normally listen at -30 to -40 dB, try lowering what you think is a good listening level for a particular piece of music by 5 or 6 dB and you may well find yourself thinking that the sound is a bit more closed in. I think that sort of comment is more a comment about how our overall perception of sound changes as we turn the volume down to lower than our preferred levels and it's equally true for most of us, it's just that we each have a different preferred listening level.
Thank you for your answer David.  It makes sense,