Moved from medium attic like room to larger room, everything is too bright

IMO, furnishings and artwork accomplish as much as acoustic panels which have a cheezo pseudo art quality.

To be effective, bass traps need to be  H U G E. A typical control room would have traps front and rear equaling close to 25% of the room volume. Most audiophool bass traps are wishful thinking.

...I agree....also, try moving the speakers closer to the wall (etc)

and if it's your garage that's been converted why would your other half care she doesn't have to go in there if it's the garage tell her that's your stereo room she's got the rest of the house to play with try getting Townshend podiums underneath your speakers they seem to get rid of all room problems because they stop all the vibrations from going into your speakers and to the rest of your equipment and also they get rid of the constant Earth vibration as well that shakes your speakers all the time.

Damp that space down before any speaker swap.  The space is acting like the interior of a speaker, so some creative room treats will tame it from being shrill.

Sq. root of 450 sq. ft. suggests a square space with the ceiling 1/2 that.

*Ick*  Pad the cell, and even the KLH will behave. *G*

Lots to think about here and, I will try to scratch the surface of what may be going on and, later, a possible pathway for you to consider. It's very complex and I am in no doubt that what you are experiencing is due to the intervention of human hearing psychology. 

(FYI, I have been developing my audio enjoyment for almost 50 years and I reached a state of audio nirvana about 5 years ago, I have no pecuniary interest in any commercial audio technology.)

I would advise you not to make any changes too soon and certainly don't spend any money in the beginning.

How long have you been listening to the sound in the new space? You may need to give your brain time to work things out. The psychology of hearing is a wonderful thing, but when dramatic changes in the sound that we hear occurs, the brain goes into overload trying to work out why. This analytical process then takes over and masks our enjoyment of the music. During a period of weeks, the brain will ignore some aspects of what it hears and focus more on other aspects. The sound you actually interpret will be different over time, to the sound you hear today. This is why, small changes are needed with plenty of time in between for you to really understand what you are experiencing. If you don't take time, you could be missing something.

As usual, listen to lots of different music and make lots of notes, with times and dates of your listening sessions. List how you are feeling before, during and after each session. It's important to be able to reference everything that could influence your perception of sound - health, work, sport, stress, external distractions, weather, family and friends issues, etc, etc. Try not to think about your system and room - only the music. Looking back over your notes after several weeks, you may be astonished by what you described that you were hearing then, is not the same that you are experiencing later.

Regarding your "I think the room is more echoey" comment. Have you done the simple hand clap test in the old and the new room, to establish what the reverb time is? Just how different are the two room reverb characteristics? It is possible that your system was not able to reach it's full potential in the old room and you became accustomed to that sound...

Please return to this thread with your thoughts in a few weeks time. I would be very interested to read them and then, only then can some useful suggestions to help you be provided.

Best,

BP