How to treat my room? Hey guys, I‘d need some advice on room acoustics and room treatment. I wanna turn my „music room“ into a home studio. I‘ve already made several recordings in this room but I wanna make it more pleasing to the eyes and, more important, enhance the room acoustics. I record vocals, guitars, drums, etc. The enclosed picture (link) shows my room plus the measurements of it. Just ignore the green and red lines in the picture. (I live in Europe so the length units given are in Centimeters.) Mixing as wells as recording the artists takes place in the same room. The walls are made of concrete and the ceiling is made out of a material called Ytong. Oh and the room has a vinyl floor in it. So, I would like to ask you guys some questions: 1) where would be the best place to set up my monitors? Logically, I’d record the artists on the opposite side of the room. 2) How should I treat the room? I know that one should install absorbers on the first reflection points.. but yeah thats pretty much all I know. How should I treat the wall facing my monitors? Regrettably, I don’t have the money to let a room acoustics guy measure out my room. The ceiling is only 7" tall, which makes treating the ceiling most likely impossible because I would run out of head space. I know it’s not the best room for my project but I don’t have an other option. I’m looking forward to your answers and hopefully you guys can help me out. Thanks in advance, Chris.
You do know this is a subject worthy of a couple volumes of books, right? Recording, book one. Microphones, book two. Noise, book three. Acoustics, four. Speaker placement and playback system, five.

But you're on a budget. So first I would get some MDF and make shutters to cover the windows. To block out sound and create a flush flat inner surface that is easier to treat.

The windows are the big one but noise travels through air and so comes in anywhere air does. Weather stripping all the way around the doors will make a huge improvement for hardly any money. After windows and doors you are down to sealing around outlets and any other places air can get through. I'm not kidding. You will hear the difference.

Next you probably want to retain as much natural acoustic as possible, as natural sounds better than artificially added. But being a small room you'll want to avoid that small room sound. No one here can tell you exactly what to do based on a post and a sketch.

So being on a budget what you do is buy some Owens Corning acoustic panels. OC panels come in different thicknesses. 1" is fine for higher frequencies, thicker goes a little lower. A little goes a long way so be careful not to use too much.

This stuff cuts easily with a knife or razor blade and is very light weight. Use this to your advantage. Instead of following more noob advice trying to nail it on the first try take the experimental approach. Lean a couple panels against the walls, walk around clapping and listening, move em, clap, listen, talk, listen. Notice how things change as you move around, and as you move the panels around. Time spent familiarizing yourself this way is time well spent.

Now cut some 12" triangles and place them up in the ceiling corners. This is usually the most effective location but sound is funny so always experiment. Then do the same for the side walls and ceiling. 

Remember when treating parallel surfaces you can treat one or the other and retain some acoustic but treating both can be too muffling.

Also treating reflections, for playback is completely different than recording. For playback that first reflection if too soon ruins imaging. But you don't really need to be monitoring for imaging anyway. Minimal damping will probably be best. Sound travels like light. So from where you sit, if you place a mirror on the wall and see a reflection of the speaker, that is the only spot on the wall that needs to be treated. Handy trick.

If you spend a day or so doing all this stuff and experimenting like this I think you will be amazed at the transformation you will be able to attain for only a very small investment. Everything you need for everything I've mentioned will be well under $500. But it will sound like a million.

Then all you do is wrap the panels in some fancy fabric and boom, it will look like a million too.
Thanks for all the answers. Regarding millercarbon's post, yeah I know that my question is part of a big topic but I just wanted to get some food for thought. I really appreciate your detailed answer. Definitely trying out leaning some acoustic panels against the wall and "tuning" the room to my taste. Still, there some questions remaining in my head and I hope you guys can answer: First one would be, wether I should use Owens corning acoustic panels or Rockwool as material for the absorbers. Second, does it make any sense to put diffusors in a room this small? Third, an last one, where should I place the monitors haha, ignoring all the physics, looking at just the plane measurements of the room? Big thank you to all who give/gave me advice. Have a good one!
Dang Millercarbon, I wish someone would have broke down acoustic panel placement for me like that 6 months ago.  Would have saved me 6 months of moving my panels around and figuring that out myself...

I dig this site, but you may want to check out Gearslutz.  That is mostly pro audio guys. 
Chrismusic, millercarbon gives you some great advice. Regarding Owens Corning v. Roxul, I would definitely use Roxul. It's nontoxic--you can handle with bare hands--and its acoustic properties are excellent. I use if for my bass traps and panels/cloud. One thing to avoid is foam--it's almost useless for a recording space. A mix of diffusion and absorption can be wonderful, but that might take the input of a studio designer unless you're willing to spend a lot of time and some dollars experimenting.