https://www.sweetwater.com/store/detail/SubDudeII--auralex-subdude-ii
2. There are certainly many room treatments out there (from diy to expensive, which can make a big difference. 3. I would consider changing your speaker cable (don't know what you have, but I recently purchased some mid-range, older model (2012?) MIT cables that seem to control what I could describe as a loose-ness or modulation in frequencies and certainly 'cleaned up' any diffusion in the response on both frequency extremes). But the fact that you mention the Pureaudio as something you would consider may indicate that you are looking for a different presentation. Some people love Wilsons, or Magicos, etc. and others like panels or OB speakers, others couldn't live without the inner warmth of SET and the dynamics of horns. I would do a little self-inventory to determine "gotta have that magic midrange", and or "can't have boomy bass", or "must have wide open soundstage", etc. ... and go from there.