Slap Echo

[MOON]

In my soundroom , I have the 1st and 2nd reflection points treated as well as 1/4 round asc tube traps in the corners behind the speakers. As I went through the room from the back to the front clapping my hands to see if there was any slap echo in the room, there is definately a big slap echo effect (ringing) just as I passed the speakers moving to the wall behind the speakers.

Would that indicate that another 2x4ft absorbtive panel would be required on the side walls just behind the speaker? I think if memory serves that Jon Fo recommended this very spot in another thread. Any suggestions please. This seems to be the only problem area.

I don't have any treatment yet behind the speakers and have absobtive treatment behind the listening position as well as the previously mentioned points.
Thanks

 

[FISH_MAN]

can I see a pic of your room "don't bother cleaning up" i just would like to get an idea what we are dealing with. slap echo is really bad especially if you can almost count the times.

 

[MOON]

The room is 12x20. When I clap my hands in the center of the room just behind the speaker position is where I get the slap echo.I have 5 ft distance between the wall behind the Odyssey's and the panels. I was wondering if another treatment would be required on the sidewall area there.These pictures were taken before the chairs went in , 3 side by side at the listening area. I have Micheal Green room tunes in the back corners. Maybe perhaps some triangle echo busters would also help in the upper corners where the walls meet the ceiling.I had to put the 1st reflection treatment horizontal due to the window at that location.Picture 3 will let you visualize where I am considering the extra treatment behind the speaker.
Cheers

 

[Feltran]

I'm certainly no expert, but your room looks quite good to me. If you're not happy with the acoustics, the one thing I might suggest is some acoustic panels on the ceiling. Panels beside the speakers certainly couldn't hurt (That's your largest section of untreated parallel walls), but I'm not convinced that it's necessary.

 

[theWB]

I'm no expert either, but I would treat the front wall.
I like some absorbtion directly behind the speakers.
I'd also experiment with some between the speakers.

 

[JonFo]

Hi Moon, I’d recommend either or both of the following:

Place RealTraps Mini-HF absorbers behind the speakers (pretty much butted up against the corner treatment)

OR / AND

Same treatment on the side wall at the first reflection point of the rear-wave bounce from the front wall.

Your room is small enough and your placement of the speakers such that you currently have less than a 10ms reflection time for the bounced rear wave. This causes noticeable, and objectionable comb filtering.

Experiment by relocating one of your other treatment panels (as long as it’s fully high-frequency absorbent) at either of those locations and see how that works for you.

 

[C.A.P]

Definitely between them, and some corner treatments too.

 

[Feltran]

So now that you've gotten a few opinions, if you listen to all of us you'll have every square inch of drywall covered with acoustic panels :ROFL:

 

[MOON]

Jon,

When you mention treatment of the 1st reflection of the back wave on the side wall, approximately where would that be? Would it be safe to assume the halfway point between the corner and the distance to the panel? I know how to get the 1st and 2nd reflectiion points with the mirror as you have noted I have already done, but how exactly do you pinpoint where the rear wave bounce hits the side wall?I will have to get that high frequency mini trap sometime. I am in Canada and will have to order it from the U.S.A

Cap , when you say between them , do you mean a horizontal panel below the window behind the speakers?and I assume by corner treatments that you mean the wall/ ceiling corners.I only have room for the echo buster or asc tri corner traps. With the door there, the real trap corner traps wouldn't fit.

Feltran , good observation and a funny one at that. Actually when I built the room before putting up the drywall, it did sound good with all the Roxal safe and sould insullation.

 

[C.A.P]

Yes between them at ear level. The window is not helping you either. That should be covered and the corners may need some 8 inch corner foam blocks as you may want all the bass you can get !

 

[MOON]

Cap,

I tried to drywall that window in when I was building the room, but my better half would go for it . Hey,at least I got my soundroom (dream come true). Those blinds on the windows are Hunter Douglas black out blinds which have a foil in them to keep all light out. I assume they would be reflective for sound. The blinds are for the future pj and screen.

 

[68sting]

I'm still trying to learn more about accoustics so take this with a grain of salt. I have noticed on another forum it seems common to buy OC703 insulation and cover it in GOM(or any fabric you can breath through). Cover the whole wall ear level down with the OC703 and add bass traps in the corners. This kills most reflection points but still keeps the room alive by not treating the upper portion of the wall.

 

[Nielsen]

I would put two huge madrasses directly behind each speaker, read the SL3 review in Stereophile where they absorb the rear wave....
http://stereophile.com/floorloudspeakers/145/index6.html

 

[DTB300]

If you do not want to use fiberglass or rock wool, bonded acoustical cotton is another option - either the 2" or 4" versions. Great stuff to work with (no itch, no fibers, etc.) and has equivalent absorption as fiberglass. I made first reflection traps and some front wall absorption with the 2" stuff. Outperforms the Auralex stuff, which I replaced with the bonded cotton - night and day differences IMO.

Here is a great place to purchase it:
http://sensiblesoundsolutions.com/index.php?cPath=22&osCsid=0cc8003e5e0de49e8c022befd6d96e66

 

[tonepub]

Personally, I think that door with the glass window is probably hurting you...

Just for a quick fix, try putting a thick blanket over it and see what happens.

 

[FISH_MAN]

I agree a thick blanket or tarp of some kind I really do not like to much sound
coming from in back of me