Soundproofing and room correction for apartment?

Elizabeth makes some great comments. Go slow, one object at a time so you can sense the change. As to the WAF 'canvases on the wall', best to try some ceiling to floor lined drapes in key spots. If you pull the drapes out from the wall two inches, things like echo busters etc. can be mounted behind them so all that is seen is the drapes. JC Penney makes some great look drapes that are very inexpensive. Hey, you could even use that hideous foam carpet padding on the walls, covered by the drapes.

Also, measure the sound in your room, step by step. There are some great free software programs that can be used so you can 'see what your hearing'.

Soundproofing and room correction are two different animals. Soundproofing a room deals with adding mass such as adding another room inside a room. That of course would be somewhat costly. So unless you own the apt it would not be worth it. Now sound correction is much easier on the pocket book and there are many ways to accomplish this. The problem right off is your room is a perfect square with high ceilings.The rug will do very little with controlling sound. The best move would first to tame bass with upper corner traps and bass traps where the walls meet. You should use no less than 4" panels as long as WAF gives you the nod. Use panels in white.I say in white because the room is small so not to close it in. Once the bass is taken care of, most things will fall into place sound wise.Buy her a nice piece of Jewelry. That will give you a stronger handle with room acoustic.

There is not that much one can do to soundproof an apartment that does not involve some construction work. What you are already planning is almost all you can do in that area. The use of carpeting, particularly with a very good pad that is designed to reduce sound transmission is the most important thing you can do. Wall treatments may reduce the amount of higher frequency transmission, but, bass is almost unstoppable without major work. An acoustic isolation platform under the speakers (instead of spikes or couplers) can help with isolation and actually improve the sound (e.g., Symposium Svelte Shelves) of the system.

Major work can be as little as adding another layer of sheetrock to the existing walls. There are adhesives that are designed to provide some acoustic isolation between the two layers ("Green Glue") and these are quite effective.

If you can't really isolate the walls, your best approach is to get your system/room to resolve and provide satisfying sound at LOWER volume levels. It appears that you are well on the way in those respects. I personally like the way Devore speakers sound at lower volume. Tube traps can do a lot to improve the sense of clarity and articulation in the system. Tapestries on the wall can tame higher frequency slap echo (try these first, without any special, ugly, acoustic treatments). Go slowly with acoustic treatment panels because it is easy to over do them and make the room sound sterile. Bookshelves and record racks make terrific sounnd diffusers (particularly if all the records are not pushed in all the way so that they create an irregular pattern.

Choice of speakers can also dramatically affect the amount of sound transmission. When I switched from electrostatic speakers to regular dynamic speakers I notice that there is a LOT more sound spilling out of the listening area with regular dynamic speakers. With dipole speakers (electrostics, planar speakers), the back and front waves are out of phase and cancel at the sides. This means that the soundfield is much more focussed in the area between the speakers. In particular, electrostatics work well in apartment situations because of this dipole cancellation and their ability to sound good at lower volume (bulky size and placement demands are the downside).