where should the speakers stand in a room and how can I make an acoustic isolation

[Eetu]

I would also make sure not to sit dead center of the room.

You can try placing one speaker in one of your room's corners (on the floor as close to the corner as possible) then play songs that have repeating bass lines. Then roll/move back & forth on the mid axis of your room in your chair. You should find there's a spot where the bass is the most neutral. Most likely it's close to the golden ratio point (38% from the front wall, 0.38 x room length).

 

[andreasmaaan]

sorry,
if i make an artificial wall.the corner (see the diagram on the left).
Does it provide a symmetrical acoustics in the room?
and does that make some things easier?
like this??

Ah thanks, I see. Yeh, it probably would be a good idea. If you do this, the artificial wall should be reasonably solid if possible. Or perhaps you could turn that corner into a cupboard/storage space with a solid door on it?

Anyway, I'm just thinking this through again now, and I realise that I didn't properly take into account that sloped ceiling, which is very low on the balcony side of the room.

I've now got a different idea about how I'd do it. I know this would be a bit awkward with a lot of the stuff near the door, but if this is a dedicated mixing room then I guess that's not such a big problem.

This idea is based on the following principles:

1. Any asymmetry in the room should be back-front (rather than left-right), which will be less harmful to imaging.
2. The room is small and you're going to be mixing in it, so first reflections should be as late as possible, and generally absorbed, to optimise clarity.
3. As @Eetu mentioned, you should not be dead-centre of the room.

So here's what I suggest. The grey boxes are broadband absorption (thick rockwool panels would work well):

That would catch all your first reflections other than the desk bounce (which I'd try to deal with anyway, no matter how you set up the room).

The most important absorber would be the one behind the mixing desk. You really don't want sound bouncing off the wall behind the speakers and reflecting back, interfering with the direct sound. That should be a heavy absorber (how heavy depends on the distance between the speakers and the wall behind).

The other absorbers are more optional, although a good idea IMHO. You could put the sidewall absorbers on wheels so that you can play with placement (for example, you might not want to absorb the sidewall reflections if listening for enjoyment, in which case you could move the absorbers out of the way).

You could also consider putting bass traps in wherever they fit, especially those two corners to the left of the listening position, although I'd set the system up and measure at the listening position before deciding whether/how to deal with the bass.

I realise this would be a pretty epic setup, but I guess if I was going all out turning this into a mixing studio, that's how I'd do it. It might be overkill for your needs and/or budget

And someone else may have different/better ideas ofc...

 

[duiso]

thank you all again for everything. I think this will be the beginning of a long way. I will try all of your suggestions one by one. Especially the wheeled absorber attracted my attention. It will be practical and useful. You really helped. I can understand the logic of this subject with the references and suggestions I received from you. I think I can solve this room problem with some more research, trial and error.
Take care of yourselves!! thank you very much!!