Slap echo

EProvenzano · « **on:** 29 Jan 2006, 04:55 pm »

Hello,

My room presents some very obvious slap echo from most locations.
I'm looking for suggestions to treat this problem.
Room:
14x19x8.
Wall to wall carpet
frame & drywall construction
Furniture is sparse with one leather sofa being the largest item

I have a clean slate and freedom to add almost any room treatment I desire.

TIA,
EP

Marbles · « **Reply #1 on:** 29 Jan 2006, 05:16 pm »

I added some acoustic panels by www.gikacoustics.com and it really helped deaden my room.

Highly recomended.

I have 4 of the 244's and 2 of the Bass Monster (247).

These are realitively inexpensive at $99 for 2 of the 244 and $109 for each 247. Shipping is extra.

The Bass Monsters are not yet on his website, so you might want to ask about them.

richlo · « **Reply #2 on:** 29 Jan 2006, 06:14 pm »

Hey Marbles

Nice Gallery pix at the end...

Hey can you post the pix MONSTERS you got from GIK and one of the 244..I ordered 2 of those monsters and just curious what Im going to be working with....Im going to probably use Mic stands for these and bring them up so that it is centered on the wall/wall in the front wall (If not I willjust stand them in the corner on the floor as suggested) ..Glenn doesnt have much info on some of his other products including the monsters - Id love to see the back of these, Im just curious because I might decide on different orientations on the 244 - Im hoping to see something like Real Traps where you can add a mic stand to them..Im pretty sure I can rig something up for that but just would like to know ahead of time.

Also it would be nice to know that he actually has 2 x 2 which are not on the site also (unless this is untrue - I read it somewhere after purchase), in addition he has some real nice stands for these that are in his Acoustical test pix - I think he said $47+shipping but nowhere on the site does it mention they are for sale...Hope Glenn reads this and has his site update with this -

Should receive them next week sometime..I think

ctviggen · « **Reply #3 on:** 29 Jan 2006, 07:09 pm »

Technically, slap echo is caused by two parallel walls. See:

http://www.wilsonaudio.com/technotes/roomacoustics.shtml

If you put acoustic panels in the corners, the effect on slap echo might not be much (these will have an effect on room response, though), depending on what one means by "slap echo". This company makes products for slap echo:

http://www.asc-hifi.com/products/soundpanel.htm

The sound panel and soundplanks are specifically for slap echo. RPG also makes similar products.

Russell Dawkins · « **Reply #4 on:** 29 Jan 2006, 07:41 pm »

One thing to keep in mind is that slap echo, although not formally defined, usually refers to standing waves at mid and upper mid frequencies. This usually implies parallel opposing hard, flat surfaces. Only one of these surfaces needs to be absorptive or diffractive to prevent the wave from "standing".

Addressing the absorptive part and neglecting the diffractive, that would mean that if the center front area on the wall behind the speakers is absorptive (for me, that's a starting point), then the center area on the rear wall could be flat and reflective, although I prefer it to be diffusive and irregular.
If the outer parts of the front wall were untreated, then the equivalent parts of the rear wall should be absorptive.

To reiterate, only one of any two opposing parallel reflective surfaces needs to be absorptive.
Except for the area of first reflection, I don't think you need to treat the ceiling, as you have wall to wall carpeting.

EProvenzano · « **Reply #5 on:** 29 Jan 2006, 08:16 pm »

Quote from: ctviggen

Technically, slap echo is caused by two parallel walls. See:

http://www.wilsonaudio.com/technotes/roomacoustics.shtml

If you put acoustic panels in the corners, the effect on slap echo might not be much (these will have an effect on room response, though), depending on what one means by "slap echo". This company makes products for slap echo:

http://www.asc-hifi.com/products/soundpanel.htm

The sound panel and soundplanks are specifically for slap echo. RPG also makes similar products.

Thanks Bob,
The top of the Wilson article illustrates exactly what I'm experiencing.
I'm not certain how slap echo and standing waves are related but I belive the sound I'm hearing is due to parallel wall reflections.

Russell,
I like the idea of treating one opposing wall instead of both. Would there be any detrimental effect if I were to treat both? I've read a little bit about LEDE rooms but don't understand how treating both sides could be bad.

Thank you everyone for your specific product recommendations. I'll explore them all.

I'm curious if the eigth nerve corner products will reduce slap echo. Any thoughts? I like the eighth nerve product since is is relatively unobtrusive.

TIA,
EP

zybar · « **Reply #6 on:** 29 Jan 2006, 08:18 pm »

Both Eighth Nerve and Echo Busters make corner treatments designed to reduce and/or eliminate slap echo.

I own both and can say they both work as advertised.

George

Marbles · « **Reply #7 on:** 29 Jan 2006, 08:19 pm »

I also use the 8th Nerve response corners and seems. They didn't do much for slap echo in my room.

klh · « **Reply #8 on:** 29 Jan 2006, 09:00 pm »

Please describe the 247s. Are they really 7" thick? That's crazy... why not get a pair of 244s for $99 instead one 247 for $109? You could double up the 244s (getting an extra inch of depth) and save $10 while you're at it. I must be missing something.

gonefishin · « **Reply #9 on:** 29 Jan 2006, 09:01 pm »

I've got eighth nerve corners, seams which did help a bit. But the large Knauff fiberboard seemed to make a much larger improvement throughout the room. Still, the corners are nice to just throw up into the corners (go figure

)

dan

EProvenzano · « **Reply #10 on:** 29 Jan 2006, 09:22 pm »

Thanks guys.
More questions....

Why do we commonly see room treatments placed in vertical arrangements?
Would a horizontal row of 2' wide panels around the entire circumference of the room, positioned at ear height, be a good idea with respect to slap echo?

My mind tells me that any sound wave angling up or down from the listening plane would eventually find its way into my carpet.

Marbles · « **Reply #11 on:** 29 Jan 2006, 09:23 pm »

Quote from: klh

Please describe the 247s. Are they really 7" thick? That's crazy... why not get a pair of 244s for $99 instead one 247 for $109? You could double up the 244s (getting an extra inch of depth) and save $10 while you're at it. I must be missing something.

They are 7.5" thick. The 244's are 5.5" thick each. They seem to be made from different obsorbing material. The 244's seem to be made from ceiling tile, and the 247's seem to be made from a fiberglass insulation product, but it's not the pink stuff.

For my applications, one 247 was better than 2 244's, but that might not be the case for you.

klh · « **Reply #12 on:** 29 Jan 2006, 11:07 pm »

Interesting. The website says the 244 is... 4" inch thick 8 pounds per cubic square foot acoustic mineral treatment. As such, I assumed the 244s were 2' x 4' x 4" compressed mineral wool. I think the extra depth comes from the frame being behind the absorbant material. Their website mentioned they do that to keep more of the absorbant material open to absorption... I wouldn't be surprised if it's done that way to keep the absorbant material 1.5" off the wall, too. Are they easy to attach to walls and particularly wall/wall and wall/ceiling corners? How do you have the 247s placed in your room?

Marbles · « **Reply #13 on:** 29 Jan 2006, 11:36 pm »

Quote from: klh

Interesting. The website says the 244 is... 4" inch thick 8 pounds per cubic square foot acoustic mineral treatment. As such, I assumed the 244s were 2' x 4' x 4" compressed mineral wool. I think the extra depth comes from the frame being behind the absorbant material. Their website mentioned they do that to keep more of the absorbant material open to absorption... I wouldn't be surprised if it's done that way to keep the absorbant material 1.5" off the wall, too. Are they easy to attach to walls and particularly wall/wall and wall/ceiling corners? How do you have the 247s placed in your room?

I have the 247's sitting on my raised hearth and just underneath the mantle.

I have one 244 resting on it's side on the mantle, 1 244 on the back wall on a little shelf that was built in. 1 244 is on a side wall near the back rresting on a rack of TV trays while I figure out if that's where it's going to stay, and 1 244 is sitting on an SVS ultra sub in my front right corner.

The 244's look VERY easy to hang like a picture...your right about the frame in back adding the extra 1.5". They come with eye screws attached.

The 247's have eye screws but with their weight, might be a little tougher to hang.

Glen recommends plant hangers to mount between the ceiling and wall. I haven't tried this yet.