Soundproofing a room without deadening the sound

I'm turning a bedroom in my apartment into my listening room/office. The room backs up against my neighbor's room.

He's never complained about noise, but this will be a whole different level. Any suggestions for sound-proofing the room without deadening the sound or breaking the bank?
****Any suggestions for sound-proofing the room without deadening the sound....?*****

One has very little to do with the other.

****....or breaking the bank?****

Don't know what you consider breaking the bank, but if you are talking about soundproofing vs just attenuation it is VERY expensive to do correctly (effectively). "Room inside a room" is the only way. Having said that it's possible to help matters by adding mass to the adjoining walls, adding foam insulation inside the adjoining walls, sealing all moldings and outlets and possibly suspending your speakers so there is no contact with any surfaces. Lots of info available on line. Good luck.

Here's a good thread for you to read,

Also, there is a link in the thread listed as "Sound Proofing Company", so be sure to click on it as well, extremely good information.
Easiest is use earphones. Practical, and no noise whatsoever disturbing your neighbor.
Acoustical treatment and sound proofing are like apples and oranges. Acoustical treating a room is rather a cheap affair if you are doing a home brew project. Sound proofing involves almost building another room within a room. The best of luck.
Not practical, but I once had a buddy in a condo situation who put 2 inches of cork on an adjoining wall.