Room Treatment

The active ingredient in many acoustic panels is Owens Corning acoustic panel, available at many hardware stores in 2x3 ft panes of 1" or more thickness. Its a whole lot cheaper and educational to try a couple of those in different places and figure it out on your own. Frankly no professional can do any better unless they are on-site and able to hear your room. Unless you think they somehow have divine powers of observation, teleportation, or whatever. Which some here do. Not kidding. But for all the rest, DIY.

Typical places to try are first side wall reflection, front wall between speakers, and to damp flutter echo wherever two parallel walls are reflecting back and forth.

This will cost maybe $20 and take maybe an hour or so. When you get the rough idea then try cutting them to as small a size as you really need. Then finally cover with fabric.

Or pay through the nose and talk yourself into believing it was worth it.

 

I have GIK treatments.You can send them a picture of your room, fill out the form online and someone will get back with you to advise and get you started on the best options for your space.You don't have to take measurements,but it's helpful to actually see what is going on with the sound waves in your room.

I have GIK too.  Call them or send a pic of your room and they will tell you where to start

I've used GIK and yes, I made room measurements using REW software first.  Before you buy anything, do yourself a favor and optimize speaker and listening position before you begin adding treatments.  Simply optimizing speaker and listening position, guided by measuring responses, can do more to improve frequency response than a whole room full of treatments.   Treatments actually help most with reducing low frequency decay times, which produces articulate vocals, and treating early first reflection points, which improves imaging.   The more you can do on your own, the more you will benefit from consultation.  GIK is a great resource, but they are in business to sell, not to help you make most efficient use of your investment in treatments.   All of the companies that sell treatments offer really good tutorials and tools on their websites.  Real traps, for instance, offers a wealth of information which I encourage you to use.  But I suggest you stick with GIK for products and advice. 

As brownsfan suggests all these companies will over-sell you. Not that their products are not good but it helps if you know what you want ahead of time but doing some experimentation. Find your 1st reflection points using the mirror method and dampen them in series using cheap acoustic tile.  https://www.parts-express.com/sonic-barrier-fwp122-studio-acoustic-foam-wedge-panel-12-x-12-x-2-black-12-pack--260-547
Dampen the front wall first then the side walls. Some people actually like the look of the tiles. Once you have it figured out you order the size and number of decorative panels you need. I am not a fan of bass traps. I have measured several rooms with and without bass traps and have not found any alteration standing wave location or intensity.
In damping the reflection points correctly you should notice that the image solidifies like a picture going into focus. Once you have the proper image you can stop. To get the best bass possible in your room get a rolling desk chair and roll your self back on forth in the area of your listening position to find the spot where the bass sounds best to you and plant your listening chair there.