SQ lacking

Oh, I think maybe cd transport-dac-preamp because if I go directly from cd transport to headphone amp then I can't listen to speakers without having to disconnect interconnects all the time?

I am going to try this, eliminating the preamp in the chain, but one would think that if you have a good preamp that the SQ would be quite good. I am trying to figure this out...perhaps my ears require more than what the Sennheiser delivers. I don't know. Hard to imagine, since they get good reviews

Some things do improve with break in, IMO. Speakers, headphones, pretty much anything mechanical.......even electronics to some degree. Have to agree with shadorne to some extent though. If it sounds bad now, it may......or may not, sound better in a week..........To some degree I to believe that we mentally "adjust" to what we hear and see. Over time we begin to accept what we hear as normal.

Were it me and it's not, I'd keep everything powered up and playing continuously for a few days, even at low volume, just to break things loose and let them get settled. Sounds like you put out some real money here, so if things don't get markedly better pretty soon I'd be having a heart to heart with the dealer.

You've gone the headphone route, so yeah, that takes your room out of the equation. If in a few days the phones start to sound pretty good, but the speakers still sound bad, that leaves two things. Either you bought a defective piece of gear that's dragging your whole system into the mud, or your room really is THAT bad..........which is addressable for far less than you probably paid for your hardware.

FWIW, I just did a pretty extensive room treatment and the difference was so great that I honestly barely recognized my own system and music, it made that much difference. Seems like you may have other issues though..................good luck and regardless of price, anything can be bad out of the box

My audio room is my bedroom. There are so many things in the way, and so much restriction for speaker placement, that I purchased the Dspeaker correction device. That will help the speakers which sound good but aren't wowing me yet. Headphones, well maybe some more breaking in, or maybe taking the preamp out of the chain. I am not sure what to feel about the concept of me "adjusting to the sound". I remember a few decades ago listening to high end equipment on vinyl and feeling wowed immediately. Thank you for all advice

You’ve got a lot of equipment there and it looks like good quality gear, so if your system just sounds bad, something isn’t working properly.

I can’t really tell you what the optimal setup would be, but I would set up each part of your system (i.e. cd, lp and headphone) one at a time, as simply as possible. Your cd spinner to your preamp/dac to your amp to your speakers only, in order to try and isolate any piece of gear that might be causing a problem or, in another way, finding out which components are working correctly. In setting up your headphone system, just go from cd spinner to headphone amp/dac to headphones. Leave the preamp/dac out.

Try that and see what happens and let us know if it helps.  You can eventually get everything hooked up together, but with all those connections and components it's easy to get something hooked up wrong when you're connecting it all up at once.