I used professional room treatment products from RPG Acoustics when I had a dedicated Home Theater / music room about 18 years ago. After moving to a new place, the main system which now comprises of different amps, sources and speakers is located in an untreated living room. Ironically, the system that is currently in the untreated room sounds better than the system that was in a treated room.
Although room furnishing is not a substitute to commercial room treatment products, I find them to work reasonably well within their limits. I have thick curtains behind the speakers and a high pile rug covering a large area of the floor. A couch on the left wall and the equipment on the right wall. Believe it or not, just by pushing the rug 2 inches away from the speakers have a profound effect to the sound in my system.
The placement of speakers is extremely crucial in getting the best optimized sound from the system apart from the employment of isolation devices for both speakers and equipment, and finally proper or adequate furnishing in the room. It will all add up to the sound. My personal experience is that a proper or optimized placement of the speakers will resolve most issues of a bad room. The rest(equipment, cables, isolation etc.) will just improve the sound a bit more. Of course, room treatments is one of them.
In my opinion and experience, commercial room treatment products are nice and effective but are not a must have.
