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Hello,

I am currently trying to adjust the acoustics in my home-studio (mainly for mixing) and need your help to sort out some issues!
It's a 2,30m x 3,70m room (yes, it's metric, please continue reading) with carpet on the floor (about 2-3cm).
Cieling is about 2,40m high. It also has a small space after the door:

My monitors are Mackie MR-5 which are quite fair budget-level monitors placed at ear level, driven by a MOTU AudioExpress interface.
I measured the response of one of the monitors and it seems quite flat. I am using a Behringer ECM-8000 for measurements.

Facts about the room:
- when clapping your hands, you can hear a clear metallic ringing lasting about 200ms after the clap.
- opening the room door and breaking the small space helps for this, but not completely.
- when bass is playing loud in the room, I cannot hear specific bass resonnance in the small space before the door.

I have tried placing my traps and absorbers in the following manner:

wall traps: 1150 x 575 mm, 50 mm thick, 65kg/m3
corner trap: 575 x 575 mm, 100 mm thick, 65kg/m3
foam absorbers: 1000 x 1000 mm, 70 mm thick, quite light (about 20kg/m3)

- wall bass traps are placed about 8cm away from the wall
- foam absorbers are put against the wall
- closet is open on the right side, filled with clothes

The main problems in the room (according to REW measurements) are two persisting bass frequencies: 130Hz and 150Hz that tend to become too present.

Questions:
1. During adjustment, the "wall" bass traps and foam absorbers are not held firmly at 8cm from the wall, they are simply placed on a supporting object:

Does this heavily effect the performance of the traps?

2. Changing the traps and absorbers placement had little effect on the room's bass response, for example covering the window with a bass trap or not has very little effect.
What other factors am I overlooking?
I separated the speakers from the desk they are put on by a block of 15cm of foam and made sure the desk was not resonnating/vibrating heavily with bass frequencies.

3. As mentioned earlier, when clapping your hands, you can hear a clear metallic ringing lasting about 200ms after the clap.
What can cause this?

4. Can you suggest a potentially more effective speaker placement?

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Comments

kmetal Sat, 03/15/2014 - 22:47

Have you oriented the room the other way. I would try facing the window and having the closet act as a bass trap, plus that entry way will create a longer path for the bass to travel, before it comes back and causes problems. The absorption panels should be placed on the ceiling above you, and to the side of your head as a start. Your foam absorbers are not going to effectively absorb bass frequencies and will likely not do much below 1k. They're really too thin to absorb bass.

Space Sun, 03/16/2014 - 10:26

Read this thread: http://recording.org/index.php?threads/newbie-control-room-acoustic-treatment-help.55413/#post-410639

Also, you have two options with a carpeted floor.

Either REMOVE the carpet since it is absorbing mids/highs indiscriminately OR place A hard type panel underneath your monitoring area, like Plywood or Hardboard.

I would remove it completely since it is the easier of the two.

You have to consider that in a mixing environment you must always maintain symmetry...ALWAYS. You must look at everything you do as if you were using a mirror in that what happens on the lefthand side should be mirrored on the righthand side.

I agree with Kmetal in repositioning the mixing position but for other reasons. The door way hall is creating a coupled echo small though it may be, but it is altering the balance. Now if you could install a heavy drape at that hallway and create a more balanced environment that might do the trick. Remember...mirror... so you would do the same thing to the right hand side.

Whatever it is that you do you have to balance the mixing area...your sitting position now has your right ear hearing early reflections at a faster rate than the lefthand side and the lefthand side has the coupling effect of the hall.

Your absorption is not helping you do anything. Like I said, read this thread: http://recording.org/index.php?threads/newbie-control-room-acoustic-treatment-help.55413/#post-410639

Fadi Mon, 03/17/2014 - 02:30

Hello,

Thanks for your input guys, I changed my disposition since my first post to something which makes more sense. It also closer to what you guys suggest:
- turned 180° facing the window
- more symmetry.
- use the closet as a bass trap (closet is filled with clothes)

Here is my new disposition:

This is how I'm thinking of putting the traps/absorbers. I only possess for now 2 trap panels, the basic foam absorbers and the corner trap.

How would you suggest treating the small area at the beginning of the room? Would some sort of thick curtain suffice?

Concerning the hard wood under the speakers, those are positionned on a hard woodden, 2-story desk (with isolation). Would that be enough?
I only have discrete absorbtion issues in mids and highs (a bit at 2kHz and some at 8kHz), but nothing drastic.

Thanks for your help.

Fadi Wed, 03/19/2014 - 02:46

The traps and absorbers are EQ Acoustics:
wall traps: [="http://www.eqacoustics.com/products-page/acoustic-treatment/spectrum/spectrum-studio-bass-trap-50-l"]EQ Acoustics Spectrum Trap[/]="http://www.eqacoust…"]EQ Acoustics Spectrum Trap[/]: 1150 x 575 mm, 50 mm thick, 65kg/m3 (placed 5 to 10 cm away from the wall)
corner trap: [[url=http://="http://www.eqacoust…"]EQ Acoustics corner bass trap[/]="http://www.eqacoust…"]EQ Acoustics corner bass trap[/]: 575 x 575 mm, 100 mm thick, 65kg/m3
foam absorbers: [[url=http://[/URL]="http://www.thomann…"]t.akustic 5020[/]="http://www.thomann…"]t.akustic 5020[/] 1000 x 1000 mm, 70 mm thick, quite light (about 20kg/m3)

kmetal Thu, 03/20/2014 - 02:29

We'll I'm not an acoustician, but I'd start by straddling the bass traps floor to ceiling in the from and rear corners, and invest 6 more mid/hi absorption panels. Put four on the walls at the reflection points, and three above your head/speakers to form a ceiling cloud. That's a pretty good generic start.