Sounds good, glad it was fun
I'm really grateful for the help!
1 and 2 sounds like they might be much of the issue
3. I think it's a combination. Power amp with a need for more voltage than the one we had before (the last one needed just 0,8V), speakers on the lower end sensitivity wise (87,3) and not a large room, but not small either, around 30-35 square meters.
The speakers we had earlier had a sensitivity of 93 and with the then power amp just needing 0,8v to be driven fully, it was blaringly loud at around -15 for music in stereo.
Yes, audesseyed with the new amp.
I'm struggling to understand the last part. The Marantz is the power amp. It has a power amp direct button that I push when I use the surround receiver, I use the Marantz alone for playing vinyl records, cds and a lot of other music. However, sometimes when I want a little more oomph in the lower frequencies I use the Denon with its connected subwoofers as a preamp so to speak for the Marantz, but it's still the Marantz that's the amplification for the front speakers.
I guess the point I'm trying to make (rather badly) is that if the Marantz alone (without the Denon as a preamp and therefore without subwoofers) is able to drive the front speakers well over 100db without any distortion, it should be able to do that acting as a power amp for the Denon too, especially as there's two hefty subwoofers playing as well then.
And the Denon should be able to give the Marantz enough voltage to reach its full volume because the Denon can go as high as 4.5V without distorting and the Marantz just needs 1,7V. But, for some reason, it doesn't happen when I play music through the Denon at 0db master volume. I just get around 94db peaks then even if I know that the Marantz at a reasonable blast is able to produce over 100db alone.
(I'm always talking about measured sound levels, not just perceived)
It can be low output levels from the music sources connected to the Denon, it can be something with the gain on the power amp direct input on the Marantz or it can be that the Denon reaches 1,7V on its pre outs over 0db master volume.
I think it might be due to low output from the sources as you say, that to me sounds like the most plausible explanation (especially since the internal Airplay on the X3300 reaches the volume levels that I would expect), but the thing I'm not sure of is how much I can compensate for this by turning the volume over 0db.
Maybe if I try really gradually and back down if anything sounds strained. Or, alternatively, I'll try to learn how to use our multimeter without short circuiting anything