First hand experience (stories about room treatment) needed

Unlike @jaytor my room is pretty small(15x13). Mike from GIK focused on bass traps and addressing the firs reflection points. All absorption. And it makes sense - the room is not large enough forbthd the diffusors to be effective. The bass traps I ended up with, per Mike’s recommendation, are the corner tri-traps with range selector (limited high frequency absorption to avoid deadening the room too much).

The gains - tighter, more tuneful and articulate bass, better coherence in midrange (bass doesn’t muddy it up anymore) and more focus with better width and depth of soundstage. Also, at higher volumes the room is no longer overloaded. 

That’s pretty much it! Happy with results so far. 

I worked with Mike Major over at GIK Acoustics. I sent Mike the dimensions and pictures of my room and he provided a recommendation that was pretty much dead on. I just completed it yesterday by installing ceiling panels.
Take a look at my system page for pictures.

You can also download REW and measure your room (you will need a mic) and send that to GIK in addition to the info I mentioned above.

Room dimensions will dictate the requirements for absorption, diffusion or a combination of both.

I would suggest you treat your first reflection points at least on the side walls and also add diffusion.  Sometimes the venders want you to add a whole bunch of panels but it can lead to over damping the room.  The floor may be your biggest issue if it is acting like a drum.  I had an issue since I am on a second story room with a suspended wood floor.  I added the Townshend podium platforms and it cured the drum and resonance problems.  Some have had a good experience with Isoacoustics footers.  Also, if you have easy access to the crawl space perhaps you could stiffen up the floor.  

The trick to room treatments is to not use too much absorption. It's almost impossible to use too much diffusion. 

Unfortunately, good diffusors are much more expensive than absorbers. There are inexpensive diffusors available, but they are not anywhere near as effective as good quadratic residue or skyline diffusors. You basically need diffusors that are at least several inches deep (ideally 6" or more) to achieve any diffusion at midrange frequencies.

My room is 17' x 29' x 8' with the speakers along the narrow wall - about 7' from the wall behind and about 4' to the side walls. My walls are mostly cinderblock with stone floors, so without some absorption, the room was super live. But initially, I overdid it a bit. 

I used GIK absorber/diffusors behind the speakers, and these proved to do too much absorption and not enough diffusion. I replaced these with ATS quadratic residue diffusors, which significantly improved the liveliness and sound stage. 

I have dipole speakers, so my treatment approach may not be as effective for box speakers. 

In addition to the QRD diffusors behind the speakers, I have some 2" absorption panels on the cinderblock walls to the side of the speakers. A total of six 2'x2' panels on each side covers about 25% of the wall area in the front 10' of the room. I'm also using DIY tube traps in the front corners (behind the speakers). 

I have a ceiling cloud using six GIK 242 panels (2'x4' with about 2" of absorption material) and a large wool area rug. Since I'm now using line array speakers which fall off fairly rapidly in the high frequencies above and below the speakers, these floor/ceiling treatments don't do as much as they did with my previous point source speakers, but help keep the room reverberation time to a reasonable level. 

The side walls closer to the listening position have GIK art panels with scatter plates. These do a modest amount of diffusion and absorption. 

Overall, I'm very happy with the results at this point, but I did do a bit of trial and error to get it dialed in. 

My total investment in room treatments is about $7K, so not exactly budget, but I have a fairly large room and purchased commercial products for everything except the corner bass traps. You can certainly save a fair amount by building some or all the panels yourself. 

You can see my room treatments in My Virtual System page.

OP- I treated all 1st reflection points all four walls and the ceiling with Primacoustic panels. Room sound went from bright and shrill with horrible imaging to neutral and relaxing with a holographic soundstage. My pics are in virtual systems.

Spent about $1500 about 5-6 years ago.

Best $ ever spent. Dramatic improvement.

Greetings 

Last year I upgraded the acoustic panels in my room. For many years I used Sonex  foam panels. Worked ok for many years.

I upgrade my panels to “Olanglab slot Diffuser/Absorption panels. I highly recommended them. I purchased them thru Amazon. They cost about $120.oo for 2. They work very well. Many companies sell them under different names. They are on my front, side and back walls. There are 12 of them in my room.

For first reflection points I purchased “Bubos Acoustic Panels”. Purchased them thru Amazon also. They cost about $100.00 for 6 panels. 48”x12”x1/2”. They are also installed on my ceiling. There are 18 panel in the room.

Recently I purchased 4 Gotham N25 Diffuser panels for my front wall. They cost more and look really good. I think the slot diffuser/absorber panels work just as good.

 I’m very happy with the sound of my room. Total cost without the Gotham panels was about $1000.00.

I built my own 20” Tube Bass Traps many years ago. Cost for 2 was about $300.00. Work really well.

You can see the Slot Diffusers/Absorption panels in my virtual system.

Your room is one of the most important components of your audio system.

Joe Nies