Sound quality vs. volume


Looking for a bit of expertise here:

I recently made a few changes to my setup and while overall pleased with the results, I’m on the quest for better.  I’m hoping you all can help me diagnose an issue I’m hearing.

When listening to music at lower volume levels - say less than 1/2 total volume, the clarity, imaging and dynamics come across far more coherent and “in focus”.  To use an often over-coined phrase “It’s like I’m there in the room”.  As I start to push the volume up a bit, closer to live-performance levels, the sound becomes increasingly “mushy”.  I know, a highly technical term, but the best way to describe what I am hearing.  The bottom-end loosens up - getting a bit boomy, the crispness of the mid-range and highs fade and the imaging falls out of focus.  These are all incremental with volume until I get to the point where it’s just unbearable.   

I’m no expert by any means but feel it might be room acoustics.  I already know I have a less than ideal setup with a nearly square room (21x20ft) with 60% of the surface covered with clear birch wood paneling. Some things we can’t change (easily).  I do not have any acoustic treatment, just lots of soft furniture.  What I find interesting is that my old setup (Magnepan 1.6) didn’t suffer to such a degree.  Maybe with the new setup there is more to loose?  A mystery.  

For a bit more context:  
Speakers:  Dynaudio Contour 60
Streamer: SoTM sms-200 Ultra
Amplifier: Peachtree Nova500

Within the 20x21ft. room, my speakers are 4ft. from the wall, I am seated 13ft. from the front wall (a bit back from room center). Speakers are 9ft. apart.

Any thoughts?  


wanderingmoo
It would make sense to me that when the volume is cranked that you are experiencing frequency cancellations do to the sound reflections in the room.  If you have two opposing frequencies 180% out of phase then the original is canceled out.  At low volume it would be less apparent.  As a test by placing a couple throw rugs on the wall behind the listening area and possibly experimenting in more areas to see if that helps. 
Have here an open concept space of similar albeit a bit larger dimensions. Was a nightmare and I spent considerable upgrading power treatments, speakers, amps, cables, subs....until I surrendered and rearranged the furnishing so the AV was coming out of a corner.  OMG the radical improvement in fidelity  IE top to bottom resolution/detail/definition, 3D stage, image nuances, separation and air, and tonal shadings and overall balance. Had only I started here. YEMV by degree but I believe you will be very pleased. Aside: As it's also the main living space, sound treatment properties are taken into account with decor selection and placement decisions. Seems to provide enough diffusion, absorption and life. Namaskaram
It would be a nice experiment to move the system off-axis but unfortunately the home theater and layout of the room prevent rearranging the system.  

I have explored hanging large blankets and do believe, while not perfect, I can make improvements.  
wanderingmoo, the only thing you are going to do with blankets is block very high frequencies. There seems to be a lot of misconceptions out there. First of all the frequency sensitivity of our ears changes immensely with volume. As the volume drops our ears become much less sensitive to bass and treble. I suggest you google Fletcher-Munson curves. 
Next is that every recording has a "right" volume level. This depends on the type of music and the way the recording was mastered. As an example Rock music that was recorded to playback at higher volumes sounds dull and bass-less at lower volumes. Turn it way up and it magically turns into a great recording. 
Last is very few systems can play effortlessly above 90 db and many even less. But there are systems that can and when you hear one you will know it. Trust your ears. If things are starting to sound strained or crappy it is because they are. Trying to push a system beyond it's capability is...painful. If you want more life like listening levels you have work to do. But, there are home systems that can comfortably do 110 dB which for any reasonable person is too loud. If you can make it to 100 you are in business big time. 
Several possible solutions.   The speakers should have come with foam port plugs.   They are provided for a reason.  Using them might tighten up the speakers where you now hear mushy sound.   And,  do not be afraid to pull the speakers even further from the wall. And, to sit closer in a more nearfield seating.  Near field when set up properly can help eliminate room interactions to an extent. 

I recently listened to a pair of Dynaudio Emit M10's in my system which are much smaller than yours.  It appears that Dynaudio's signature sound was designed not for blasting full volume. But, to sound good at more comfortable levels as if you are sitting a bit away from the musicians.  I really loved their sound.  But I had to return them.  Because, the bass was too strong to be keeping my apartment "peace with my lease."   ;)