speaker choice for new 20x30 audio room

Congratulations! You are clearly on the path to a great audio system. Speakers are really important… they must speak to you…they must evoke an emotional reaction. Given your room… you definitely need to push the upper end of your budget… like used Sonus Faber Olympica 3… or better… if they speak to you, like they do to me. I am on my third set… given the size of your room Sonus Faber Amati Traditional would be appropriate… but those are $30K. Take your time… if you have to get more inexpensive ones to prove the the connect, that can work… then in a few years upgrade to the next level. Over the last ten years I owned Sonus Faber Cremona, Olympica 3, and now Amati Traditional… each step has been incredible. My room is about the size of yours.

Make sure the AC is removed and quieted… big time. Otherwise it will really screw up your noice floor.

I will second the recommendation on Legacy speakers. I also run mine from a node 2i source and through an Emotiva pre amp. Depending on your true budget The Focus SE or XD. I have the XD. These 4 way speakers with their folded ribbon tweeters and dual 12 inch subs will absolutely send chills. Especially good on high quality recordings for sure. Artists like Dianna Krall and others with highly detailed recordings are absolutely mind blowingly good on these speakers. I also use an Alexa routine to turn the whole thing on through various triggers and at the same time, turn off the mini fridge to make the room dead quiet

I am running some Ryan R630’s. At your budget you could move up to the S840’s. If you haven’t finished the build out, you could double your framing and cross bracing, use glue and screws on the sheet rock and rockwool for insulation and you not only won’t need much room treatment, but you will probably create a much better accoustic environment than the post construction fixes. The key is to prevent the walls from being resonators and this has worked well for me.

Magnepan 3.7 or secondhand mg20.

I would be all over the Von Schweikert VR-10 Mk II for sale here if I had that big of a room. Twice your budget but easy to run so you could save on the amps. They may be ugly but damn.