Finding 2th and 3th reflections on side walls

Thanks for the Replay,

Yes I have a Behringer ECM8000 but I get Driver reset every time I try to Calibrate my sound Card (UAD X8P) so the people at REW told me to skip that part and just do a reading and this is what I got so Far.

Michel Doucet.mdat (1.59 MB)

First off, I don't see your speakers in the plan. You might need to move them a bit during fine tuning but you do need a starting point.

I can't remember a discussion on 2nd and 3rd reflections so I looked around and found this:

www.acousticfields.com/control-room-reflections/

If you just look at the diagrams, you'll see that the by covering a longer area on the wall between the speaker position and the listening position, you'll have all the possible points covered. If you want to figure it out geometrically, you can use a protractor and draw triangles where the angle of incidence equals the angle of reflection but that's really not necessary.

It looks like if you had a panel 48" x 48" on the side walls that will cover the whole area in question. You already have a 24x48x6 so on that side, you can just add another one but make sure they are both wide band and not covered with foil, plastic or paper like bass traps. Same with the cloud.

The cloud is a little on the small side. If you had 2, you could angle them in line with the speaker to listening position line.

To help to balance out the door corner, is it possible to hang or mount a bass trap on the door? Going floor to ceiling with the wall mounted one is good too.

Since your room is fairly close to a cube, you'll need more bass traps. Wall/ceiling corners are a good place to add them.

Do you know about amroc? it's a room mode calculator. amcoustics.com/tools/amroc?l=13.16&w=12&h=7.75&ft=true&r60=0.6 You can see how your REW graph correlates with the modes in amroc. This can help you determine what modes are where but bottomline is you need more bass traps to smooth them out. Playing with speaker and listening position can hep too. 

Hey Pasim,
I could not open the files but when I tried, I got a message to up-date REW to the current version and after installing new version it worked fine.

Spock, as I tried to tell you before, just make your your RFZ absorber "pads" larger to cover an area to include 2nd and 3rd reflections. That will then treat the 2nd and 3rd reflections too.

What is your problem with RT60?

Even though I wrote earlier that drawing out the reflections was not necessary, I went and did it anyway.

For the primary, I actually used a protractor and tried to be accurate but for the 2 and 3 I just eyeballed it. If I had done it accurately, a line perpendicular to the wall from the reflection point would bisect the angle (in half), that's what sound, light and billiard balls do. ("The angle of incidence equals the angle of reflection.")

So now you see that in general, if you want to "catch" all those reflections, treating the side walls between the speaker and the listening position will pretty much do the trick.

So do you need to "catch" the 2nd and 3rd reflections? Well they are less prominent so maybe not so much BUT remember, sound is not like a laser beam and more like a cone. So even to treat for only 1st reflections requires more than a single point and more of an area, so by expanding that area not only helps for 1st reflections but for 2 and 3, and so on.