Difference between 1" and 2" Pyramid Acoustic Foam

[seigneur_rayden]

I am planning on buying Acoustic foam pyramids and was wondering if there is big difference between the benefits on a 1" as opposed to the 2".
The price for the 2" seems to be almost double of the 1".
All suggestions and comments are welcome. Thanks
http://www.thefoamfactory.com/acoust...ramidfoam.html

[Johnny Vinyl]

Go for the 2" foam. I bought the 1" foam from one of their Canadian distributors and was disappointed by its lack of effectiveness.

[seigneur_rayden]

Originally Posted by John72953

Go for the 2" foam. I bought the 1" foam from one of their Canadian distributors and was disappointed by its lack of effectiveness.

Thanks for the reply John. Could you please elaborate on "its lack of effectiveness"?

[Johnny Vinyl]

Originally Posted by seigneur_rayden

Thanks for the reply John. Could you please elaborate on "its lack of effectiveness"?

I am pretty well in-tune with how my system sounds, and once I mounted them on the wall and gave it a few days to audition more carefully, I still realized that the room was too live. This was especially noticeable with the volume level at a higher than normal level. I would have expected a less live sound at slightly higher volumes, but that never materialized.

I'm also not sure about foam and it's overall effectiveness (regardless of how thick it is). My own experience with it has left me rather indifferent about foam.

[richteer]

Originally Posted by John72953

I'm also not sure about foam and it's overall effectiveness (regardless of how thick it is). My own experience with it has left me rather indifferent about foam.

Agreed. The OP should check out the "Acoustics Info" section of the Real Traps web site (realtraps.com), where they show the effectiveness (or lack thereof) of several products, including foam. The latter does not do too well...

[Big Daddy]

Originally Posted by seigneur_rayden

I am planning on buying Acoustic foam pyramids and was wondering if there is big difference between the benefits on a 1" as opposed to the 2".
The price for the 2" seems to be almost double of the 1".
All suggestions and comments are welcome. Thanks
http://www.thefoamfactory.com/acoust...ramidfoam.html

Buy the 4" foam. The thicker the foam, the more frequencies it will absorb. I use plenty of 4" foam. My HT room has been converted to an anechoic chamber.

These are the NRC Ratings:

NRCRating.jpg

[Blown 4.3]

are those numbers in DB's ?

[Big Daddy]

Originally Posted by Blown 4.3

are those numbers in DB's ?

Hopefully Ethan Winer from Real Traps will see this thread and give you a better explanation. In the meantime, I will do my best to confuse you as much as possible.

For musical instruments or the speakers to sound good you must have a balance between the high and low frequencies. If your room absorbs all the higher frequencies and is too dead in that range, the sound will be lifeless and tubby. If the room is too lively in the higher frequencies, the the sound will be distant, imaging will suffer, and dialog becomes too difficult to understand. To balance a room you must have a balance between the high frequencies and the low frequencies with the right amount of deadness to liveness.

The coefficient of absorption is the amount of acoustic energy a surface absorbs and reflects and is measured at different frequencies. They are not dBs. They are simply coefficients. Many people use them as percentages. For example, if a material has an absorption coefficient of 0.30, the material will absorb 30% of the incident acoustic energy, while reflecting back 70% of the total acoustic energy at a specified frequency. Although this is an ok approximation, if you are an audio purist, you simply look at them as some ratios. Please see the post below by Bryan from GIK Acoustics.


http://www.atsacoustics.com/page--Un...--ratings.html

Sound Absorption Coefficients

Sound Absorption Coefficients are a measure of how much sound is absorbed by a material or object. The ratings are expressed as a value between 0.00 and 1.00. 0 means no sound is absorbed, 1 means all sound is absorbed. A higher rating means more sound absorption per square foot of panel you buy.

Sound Absorption Coefficients are measured at a specific frequency. Multiple sound absorption coefficients at a range of frequencies help present an overall picture of the sound absorption of an object.

NRC Ratings

NRC stands for Noise Reduction Coefficient. It's a combined measure of how much sound is absorbed by a material or object over all frequencies the human ear can hear. The ratings are expressed as a value between 0 (no sound absorbed) and 1 (all sound absorbed).

http://forums.audioholics.com/forums...ad.php?t=46427

This is a common misconception. In theory, this should be correct but due to how measurements are taken and converted from Sabines to coefficients, it doesn't work out that way. It's actually a simple ratio rather than a percentage.

The reason it has issues is due to the edges of the samples. For instance, if I take a measurement of 80 sq ft of a product and get 80 sabines absorbtion at say 250Hz, my coefficient is 1.0 Now, if I get 90 sabines absorbtion, I get a ratio of 1.125 for the coefficient. How can we absorb more than 100%? We can't. However, the number is correct.

The problem is that when the formula is run, we divide sabines by the surface area of the face of the sample. This is the standard way to do measurements and calculations. However, if the sample is say 4" thick and all of the sides are exposed, and the samples are laid out as 2 rows of 5 2'x4' panels, then there is an additional 9.324 sq ft of surface area on the sides which is also absorbing and accounting for the additional sabines recorded - but this area is not figured into the coefficient calculation.

Does this mean that the measurements are not correct? Absolutely not. They are correct - in sabines. So, a 2'x4' panel with a coefficient over 1 is still providing the additional absorbtion.

When looking at materials, you must know how the tests were performed vs how you're going to use the materials. You should also always look at the sabines at the various frequencies to see what you're actually getting. Sabines per dollar is a good way to look at things in addition to sabines per unit area from a functionality standpoint.

Bryan
__________________
Lead Acoustical Designer
GIK Acoustics

Excellent References:
http://www.acoustics.com/101.asp
http://www.astm.org/Standards/C423.htm
http://www.classroomacoustics.org/library/test2.htm
http://www.realtraps.com/art_measure.htm
http://www.realtraps.com/art_testing.htm
http://www.ethanwiner.com/acoustics.html
http://www.acoustics101.com/definitions.asp
http://www.greengluecompany.com/soundAbsorption.php
http://www.acoustic-supplies.com/more-about-sound
http://www.acousticalsurfaces.com/so...sts/PEPP2G.PDF


This is the mathematical theory behind it. I am sure it makes the most sense to you.

http://paws.kettering.edu/~drussell/...bsorption.html
http://www.inceusa.org/nc07/links/Mu..._materials.pdf

[crazyBLUE]

Originally Posted by Big Daddy

Buy the 4" foam. The thicker the foam, the more frequencies it will absorb. I use plenty of 4" foam. My HT room has been converted to an anechoic chamber.

These are the NRC Ratings:

Attachment 31789

Started as a Garage ~ Then a Home Theater ~ Then an anechoic chamber

[Big Daddy]

Originally Posted by crazyBLUE

Started as a Garage ~ Then a Home Theater ~ Then an anechoic chamber

You left out the Dog House. I was banished and lived there for several months after my wife accused me of loving my subwoofers more than I love her.

[crazyBLUE]

Originally Posted by Big Daddy

You left out the Dog House. I spent several months there. My wife banished me after she accused me of loving my subwoofers more than I love her.

I forgot the dog house At least it's a nice one on Isolation bricks

[seigneur_rayden]

Originally Posted by richteer

Agreed. The OP should check out the "Acoustics Info" section of the Real Traps web site (realtraps.com), where they show the effectiveness (or lack thereof) of several products, including foam. The latter does not do too well...

Thanks for the link. It is full of good information. On another note, damn, their prices are not seigneur RAYDEN friendly.

Originally Posted by John72953

I am pretty well in-tune with how my system sounds, and once I mounted them on the wall and gave it a few days to audition more carefully, I still realized that the room was too live. This was especially noticeable with the volume level at a higher than normal level. I would have expected a less live sound at slightly higher volumes, but that never materialized.

I'm also not sure about foam and it's overall effectiveness (regardless of how thick it is). My own experience with it has left me rather indifferent about foam.

Thanks for the explanation.

Originally Posted by Big Daddy

Buy the 4" foam. The thicker the foam, the more frequencies it will absorb. I use plenty of 4" foam. My HT room has been converted to an anechoic chamber.

Unfortunately, I can't afford the 4"

Originally Posted by Big Daddy

Hopefully Ethan Winer from Real Traps will see this thread and give you a better explanation. In the meantime, I will do my best to confuse you as much as possible.
.......This is the mathematical theory behind it. I am sure it makes the most sense to you.

You actually enlighten me. Now I have a better understanding. Thanks.

See, I'm going to be renting a place that has an unfinished brick basement. Correct me if I'm wrong but it seems like I read somewhere that bricks walls are bad for sound (too much reflections). I may be very wrong.
So I am trying to gather information on what I can do to help with the sound since I can't do much in the place, being a rental.
Any suggestions on what to do is appreciated. Thanks.

[Ethan Winer]

Originally Posted by Big Daddy

Hopefully Ethan Winer from Real Traps will see this thread and give you a better explanation.

I have much to add.

First, that specific foam company is a fraud, and the foam they sell is not even acoustic foam. They took the data from Auralex's web site, fudged all the numbers up or down a bit at random to hide the theft, then claim it's data for their foam. The second graph down on the RealTraps Product Data page shows genuine Auralex foam compared to that sold by Foam By Mail, which also goes by the name Foam Factory.

Bryan's explanation of how acoustic materials can absorb more than 100 percent is from this article on my company's site:

Measuring Absorption

In particular, see the section The Numbers Game. And if you really want to dig deep into how acoustic products are measured, this article offers much more detail:

Test Methods for Acoustic Treatment Products

To the OP: If you must go with foam, and you can't afford the 4-inch thickness, buy less of it for now and plan to get more later. And don't buy from Foam Factory, no matter how appealing the lower prices seem. In this case, it's not "You get what you pay for" because you don't even get that.

--Ethan

[seigneur_rayden]

Originally Posted by Ethan Winer

I have much to add.

First, that specific foam company is a fraud, and the foam they sell is not even acoustic foam. They took the data from Auralex's web site, fudged all the numbers up or down a bit at random to hide the theft, then claim it's data for their foam. The second graph down on the RealTraps Product Data page shows genuine Auralex foam compared to that sold by Foam By Mail, which also goes by the name Foam Factory.

Bryan's explanation of how acoustic materials can absorb more than 100 percent is from this article on my company's site:

Measuring Absorption

In particular, see the section The Numbers Game. And if you really want to dig deep into how acoustic products are measured, this article offers much more detail:

Test Methods for Acoustic Treatment Products

To the OP: If you must go with foam, and you can't afford the 4-inch thickness, buy less of it for now and plan to get more later. And don't buy from Foam Factory, no matter how appealing the lower prices seem. In this case, it's not "You get what you pay for" because you don't even get that.

--Ethan

Thanks Ethan for the advice and saving me from losing my hard earned money. I really appreciate it.What would you suggest I do for my concern below:

Originally Posted by seigneur_rayden

See, I'm going to be renting a place that has an unfinished brick basement. Correct me if I'm wrong but it seems like I read somewhere that bricks walls are bad for sound (too much reflections). I may be very wrong.
So I am trying to gather information on what I can do to help with the sound since I can't do much in the place, being a rental.
Any suggestions on what to do is appreciated. Thanks.

[Ecstasy]

Originally Posted by Ethan Winer

I have much to add.

First, that specific foam company is a fraud, and the foam they sell is not even acoustic foam. They took the data from Auralex's web site, fudged all the numbers up or down a bit at random to hide the theft, then claim it's data for their foam. The second graph down on the RealTraps Product Data page shows genuine Auralex foam compared to that sold by Foam By Mail, which also goes by the name Foam Factory.

Bryan's explanation of how acoustic materials can absorb more than 100 percent is from this article on my company's site:

Measuring Absorption

In particular, see the section The Numbers Game. And if you really want to dig deep into how acoustic products are measured, this article offers much more detail:

Test Methods for Acoustic Treatment Products

To the OP: If you must go with foam, and you can't afford the 4-inch thickness, buy less of it for now and plan to get more later. And don't buy from Foam Factory, no matter how appealing the lower prices seem. In this case, it's not "You get what you pay for" because you don't even get that.

--Ethan

Thanks a bunch Ethan for this very important piece of infoamation!

[JJ]

See, now that "Foam Factory is a scam" info should've been well-known since years ago - I think everyone and their mother uses their cheap foam around here.

[Ethan Winer]

Originally Posted by seigneur_rayden

I'm going to be renting a place that has an unfinished brick basement. Correct me if I'm wrong but it seems like I read somewhere that bricks walls are bad for sound (too much reflections). I may be very wrong. So I am trying to gather information on what I can do to help with the sound since I can't do much in the place, being a rental.

First, brick reflects about the same as any other surface material such as drywall or wood. There may be small differences at the very highest frequencies, but basically they all sound the same. Full explanation here:

Surface Reflectivity

As for what you can do, bass traps can be placed on the floor sideways across wall-floor corners, or stood up vertically tipped back leaning into wall-wall corners. So mounting or holes are not strictly needed. You can also buy / make stands for both bass traps and reflection absorbers. Two examples from my company's web site are shown in the photos below.

--Ethan

[richteer]

I've only seen them at a couple of shows, but I can attest to the build quality of Real Traps', err, traps. They're very well made, and work well. In fact, this thread reminds me that I need to send some drawings & photos of my room to Ethan and work out how much cash I have available to spend on room treatments.

[StalkerVette]

Originally Posted by Ecstasy

Thanks a bunch Ethan for this very important piece of infoamation!

Ohhhh nooooooo..................

[Aerodude73]

Originally Posted by Ethan Winer

I have much to add.

First, that specific foam company is a fraud, and the foam they sell is not even acoustic foam. They took the data from Auralex's web site, fudged all the numbers up or down a bit at random to hide the theft, then claim it's data for their foam. The second graph down on the RealTraps Product Data page shows genuine Auralex foam compared to that sold by Foam By Mail, which also goes by the name Foam Factory.

Bryan's explanation of how acoustic materials can absorb more than 100 percent is from this article on my company's site:

Measuring Absorption

In particular, see the section The Numbers Game. And if you really want to dig deep into how acoustic products are measured, this article offers much more detail:

Test Methods for Acoustic Treatment Products

To the OP: If you must go with foam, and you can't afford the 4-inch thickness, buy less of it for now and plan to get more later. And don't buy from Foam Factory, no matter how appealing the lower prices seem. In this case, it's not "You get what you pay for" because you don't even get that.--Ethan

Wow - pretty harsh words there. If they're a Fraud company (for their advertised products), whom would you recommend? (is this the part where we get "From My company, of course!" ). Thanks.