Absorbers on the front wall

[Adam_Weishaupt]

Do they have to be in the same height as the speakers?And how many should i place?

[Glenn Kuras]

If you have problems with SBIR then it would go right behind them.

[SAC]

If it is needed for early reflections, they would be located where a ray tracing model would place them (think of sound acting like a 3space billiard ball).

Just a few thoughts to perhaps challenge what is often a generalized assumption.

Do your speakers actually project significant energy to the front wall? Do the cabinets actually resonate that strongly? Or is the orientation of the speakers the problem as their dispersal actually reflects of the front wall?

Before assuming you need to treat the front wall with absorption, it would be simple to measure it and determine if this is a real problem. And if it is, it will also provide you with the means to appropriately deal with it.

[Adam_Weishaupt]

i just ask at general :D what would be the recomendation?

[SAC]

I understand, but 'in general' assumes many possible situations that may or may not exist.

If reflections are a problem, absorption of diffusion may be sufficient. If it is SBIR, as Glenn suggested, absorption or relocating the speakers may be a solution. But the bigger issue is that he best answer depends on identifying the actual problem.

So it helps to identify the actual behavior such that we can more effectively address the real problems rather than all of the possible variables.

That is why I suggest simple measurements to determine what is actually occurring. Then the questions become more focused and the correct answers easier to formulate.

I hope my playing Devil's Advocate helps in demonstrating how properly identifying the real problem to be fixed contributes to actually fixing the problem and not simply creating additional anomalies, or spending additional unnecessary time and effort and money.

BTW, while we are here, what would you suggest is the best way to fix my car? ;-)
Do you see the problem? ;-)

[Glenn Kuras]

FYI,

Learn what is SBIR (Speaker Boundary Interface Response).

[Adam_Weishaupt]

yeah i will do the measurements...but at general..... would yes or no....?

[DanDan]

Adam, the simplest answer is no. RealTraps - Front Wall Absorption
However.... a bare wall between your speakers can cause a flutter if there is a similar area of bare wall behind you. SBIR is the other issue. If you chose to address it you would need pretty serious bass traps directly behind your speakers. Note SBIR occurs at the side walls also. Careful positioning can help minimise SBIR.
DD

[aleatoric]

Place the traps roughly half way between the floor and ceiling. If you have a very high ceiling or very low sitting monitors you might want to place them a little bit lower. Halfway is a good starting point though.

[Adam_Weishaupt]

or what it make more sence to just to basstrap the 4 corners of the front wall? I have a window on the front wall.

[DanDan]

Treat the 4 corners with the biggest traps you can manage. Superchunks are good.
The window is probably functioning as a bass trap already. Thump it gently and you will hear the resonant frequency. Leave it alone. You many need trapping on the back wall to prevent a flutter between front and back. Move the speakers about to 'tune' the SBIR. It may even be useful.
Read Ethan's link, it makes sense. And I have tested it here. It is true.
DD

[Jeffrey Hedback]

If you have rest of room treated and the front wall is hard...and you're getting image shift or severe smearing, it's worth looking closer at front wall. I've found on more than one occasion early reflections off console (in small rooms) can beceome problematic with the front wall.

Just don't take your ears out of the equation because your eyes and typical practices say you're done.

[Glenn Kuras]

Originally Posted by DanDan

Adam, the simplest answer is no. RealTraps - Front Wall Absorption
Note SBIR occurs at the side walls also. Careful positioning can help minimise SBIR.
DD

Good point!

[DanDan]

Hi Jeff, the devil is in the detail as always. If I had sound bouncing around between the back of a console and the front wall I would cover both probably. In many cases we have a screen or screens between the speakers so the front wall is obscured at that level. In my room I found it necessary to install a flutter control panel on the front wall above the height of the screens. There was a direct path to an area of plaster high up in the centre of the back wall. One MicroTrap was plenty. I tried an array of MiniTraps behind my monitors and could measure nor hear any change whatsoever. I do have the full size 32 inch superchunks in the front two corners though. I fully agree about set theories and assumptions versus experiment. It seems to be always best to try temporary experiments. e.g. prop a bunch of traps temporarily on the front wall and measure what happens.
DD