[bpape]

Different strokes.

Any frequencies that can penetrate the facing to get INTO the corner will also be able to penetrate on the way back out.  Those that can't penetrate it will be reflected back into the room.  Those that are partially attenuated on the way through will be again partially attenuated on the way back out.

Bryan

[Big Red Machine]

Front right from sweet spot:




Left front:



Left rear of sweet spot:




Behind the main chair:



Right rear:

[Big Red Machine]

Ceiling looking back toward seating:




Closer view of the 6" thick traps:

[Rick Craig]

Pete,

The calibration plots on the net are sometimes not accurate because it depends on which version of the meter that you have. If you have someone check it out against a good reference measurement system they can give you the correction curves.

The large dip in the 2K area is probably a phase reversal on the tweeter. Try changing the connections on the ribbon and measure again.

[8thnerve]

Different strokes.

Any frequencies that can penetrate the facing to get INTO the corner will also be able to penetrate on the way back out.  Those that can't penetrate it will be reflected back into the room.  Those that are partially attenuated on the way through will be again partially attenuated on the way back out.

Bryan

The frequencies that reflect off the face of the panel are not of primary concern.  The sound that gets behind the reflective layer (through the gap formed by the edge of the panel and the wall) will be mostly trapped between the corner and the panel, cycling until it is attenuated.  This is critical because the sound energy that returns from the corner is distorted and amplified, causing echo, reverb and frequency imbalance.  The panel traps most of it in.

[bpape]

I will say that the room does look like it has a LOT of primarily high frequency absorbtion in it relative to the amount of broadband.

Bryan

[Ethan Winer]

Nathan,

Maybe you can clarify something for me:

sound energy that returns from the corner is distorted and amplified, causing echo, reverb and frequency imbalance. The panel traps most of it in.

If sound can get through a panel into the corner, how could the panel stop it from getting back out the same way it got in?

--Ethan

[8thnerve]

Nathan,

Maybe you can clarify something for me:

sound energy that returns from the corner is distorted and amplified, causing echo, reverb and frequency imbalance. The panel traps most of it in.

If sound can get through a panel into the corner, how could the panel stop it from getting back out the same way it got in?

--Ethan

Sure.  Here is a simplified diagram.  Obviously the amounts of sound that travel between the edge and wall surface will vary with materials, distance, etc.  This is a general approximation, but should illustrate the answer you are looking for.

[Ethan Winer]

Here is a simplified diagram.

I'm sorry Nathan but I'm still confused. If 90 percent of the original wave is reflected back right off the bat, and 10 percent escapes from the corner from leaking out, then 100 percent of the sound has come back. So what has the panel done then?

--Ethan

[95bcwh]

Let's do the math right:

The 10% that goes behind the panel got amplified and become 20% of its original strength.
90% of this 20% got trapped behind the panel permanently, and 10% of this 20% somehow escape back into the room.

So the total amount of reflection getting back to the room is 90% + 10% x 20% = 92%

The question is, how useful is a panel that reflected back 92% of its signal?

Here is a simplified diagram.

I'm sorry Nathan but I'm still confused. If 90 percent of the original wave is reflected back right off the bat, and 10 percent escapes from the corner from leaking out, then 100 percent of the sound has come back. So what has the panel done then?

--Ethan

[IronLion]

I believe the idea behind 8th Nerve's product line, the triangles specifically, is to eliminate acoustic distortions that result from soundwaves collapsing into a corner, which acts as a horn.  So, with a triangle, while 92% of the sound may be reflected back into the room, it is reflected back without distortion, as opposed to 100% of it reflecting back into the room with distortion, which is what would happen without the triangle installed.  So, in short, the goal of the triangle is to promote even frequency response in the reflection from the corner and to prevent the distortions that they cause if untreated.

The only thing about their design that I'm unclear about is why there is a gap intentionally created between the wall and the triangle (panel) itself; if even reflection is the desired route, why isn't flush against all wall/ceiling surfaces the best route?  I imagine that there is a specific and more-in depth answer to this question than I can provide.   

[Glenn K]

Yea but if a woodchuck chucks wood then does a wood chuck wood.... Oh forget it!!!!!!!!!!!!!!

Glenn

Let's do the math right:

The 10% that goes behind the panel got amplified and become 20% of its original strength.
90% of this 20% got trapped behind the panel permanently, and 10% of this 20% somehow escape back into the room.

So the total amount of reflection getting back to the room is 90% + 10% x 20% = 92%

The question is, how useful is a panel that reflected back 92% of its signal?

Here is a simplified diagram.

I'm sorry Nathan but I'm still confused. If 90 percent of the original wave is reflected back right off the bat, and 10 percent escapes from the corner from leaking out, then 100 percent of the sound has come back. So what has the panel done then?

--Ethan

[Glenn K]

You either want to absorb or diffuse. For low end you want to absorb and for high end, depending on the area of the room and set up, you can go either way. The last thing you want is direct reflections off of any area.

Glenn

I believe the idea behind 8th Nerve's product line, the triangles specifically, is to eliminate acoustic distortions that result from soundwaves collapsing into a corner, which acts as a horn.  So, with a triangle, while 92% of the sound may be reflected back into the room, it is reflected back without distortion, as opposed to 100% of it reflecting back into the room with distortion, which is what would happen without the triangle installed.  So, in short, the goal of the triangle is to promote even frequency response in the reflection from the corner and to prevent the distortions that they cause if untreated.

The only thing about their design that I'm unclear about is why there is a gap intentionally created between the wall and the triangle (panel) itself; if even reflection is the desired route, why isn't flush against all wall/ceiling surfaces the best route?  I imagine that there is a specific and more-in depth answer to this question than I can provide.   

[Rob Babcock]

I can't argue you guys' logic, but for whatever the reason the 8th Nerve stuff really does work.  Until I find a house (I'm staying with my sister while I look) I won't be able to try any other treatments (but I'm still planning on it, Ethan! ), but I'd be lying if I said the Adapts didn't make a big difference vs bare walls.

[IronLion]

I can't argue you guys' logic, but for whatever the reason the 8th Nerve stuff really does work.  Until I find a house (I'm staying with my sister while I look) I won't be able to try any other treatments (but I'm still planning on it, Ethan! ), but I'd be lying if I said the Adapts didn't make a big difference vs bare walls.

As another Eighth Nerve user, I agree with this completely; whatever, however- they work. 

[Rob Babcock]

Nathan,

Maybe you can clarify something for me:

sound energy that returns from the corner is distorted and amplified, causing echo, reverb and frequency imbalance. The panel traps most of it in.

If sound can get through a panel into the corner, how could the panel stop it from getting back out the same way it got in?

--Ethan

Not to pick nits, Ethan ('cause I know you know your stuff) but you forget the air gap.  You yourself have explained that it's why traps are so effective straddling a corner.  Isn't the idea that the actual room surface isn't the ideal place to trap because the effective air velocity is zero?  (I'm trying to recall my last reading of The Master Handbook of Acoustics by Everest).  Once the wave passes thru the front, suitably attenuated, it must then rebound (losing energy in the sheetrock), pass thru more air and hit the absorber again.  And in the case of the 8th Nerve stuff, the front is reflective but the back is purely absorptive.

Don't get me wrong- your products are what prompted me to sell my Adapts in the first place.  But not because they didn't work; it's just that I want to see if your stuff works even better.

[Glenn K]

I can't argue you guys' logic, but for whatever the reason the 8th Nerve stuff really does work.  

Hey Rob,

I hope I did not come off as I to say there stuff does not work. I was only answering how acoustic products should work. 

Glenn

[Ethan Winer]

Rob (and all),

... you forget the air gap.  You yourself have explained that it's why traps are so effective straddling a corner.  Isn't the idea that the actual room surface isn't the ideal place to trap because the effective air velocity is zero?

An air gap does indeed help a conventional absorber to work to a lower frequency, and I promise you I have not forgotten that. What it really comes down to is size. A small absorber will do something, and a large absorber will do more. Always. It's that simple, assuming the core material is an effective absorber of course.

--Ethan

[Rob Babcock]

Rob (and all),

... you forget the air gap.  You yourself have explained that it's why traps are so effective straddling a corner.  Isn't the idea that the actual room surface isn't the ideal place to trap because the effective air velocity is zero?

An air gap does indeed help a conventional absorber to work to a lower frequency, and I promise you I have not forgotten that. What it really comes down to is size. A small absorber will do something, and a large absorber will do more. Always. It's that simple, assuming the core material is an effective absorber of course.

--Ethan

Yeah, they're small enough that there isn't a lot of air gap behind them.  Once I have an actual address again I'll be anxious to try out some RealTraps.

[8thnerve]

IronLion wins the prize of course.  As I've consistently stated, the Eighth Nerve products are NOT designed to be absorbers.  They are designed to trap most of the corner return wave.  That alone reduces echo and reverb, and flattens the frequency response.  They are not absorbers at all in the general sense, so therefore do not suffer from the most egregious side effect of every other acoustic product, over absorption of high frequency information.  As you should be able to see from my diagram, the whole "trapping of the corner return wave" is not a gimmick or feature of the product, it is the product.

So if your idea of great acoustics is rolled off high-frequencies and tons of huge panels on the walls and century old science, then by all means believe that size is all that matters.  After all, that's "how acoustic products should work."

Sorry for the glib response, but as you can see from the responses (no pun), they do in fact work and they work well.  Years of unanimous positive feedback supports this, as well as technical measurements.  Glenn and Ethan, you guys do a great service here helping people out with acoustics.  There is no reason to suggest that my products are somehow not effective because they don't work like yours.  I'm not selling snake oil, there is real science behind these designs.  You won't find it in Everest's tome because it's not old science.  Can't we all just, get along?

Love and kisses,
Zaphod