Acoustical Foam Egg and Multi Wave

[localhost127]

Interesting......the most sound controlled room that I have ever been in was completely lined with foam. The room was so dead it was damned uncomfortable and I could actually hear my heart beating. Foam doesnt work? I think it works pretty well.

Allan.

what was the purpose of the room?
most people dont understand why absorption is used - and blindly over-apply it.
could you define your use of "most sound controlled room"? what does "controlled" mean?

and just because you could hear your heart beating doesn't mean that the foam was even remotely worthwhile for modal issues (which is the most essential and difficult aspect to tame regarding small acoustical spaces).

[Allanvh5150]

what was the purpose of the room?
most people dont understand why absorption is used - and blindly over-apply it.
could you define your use of "most sound controlled room"? what does "controlled" mean?

and just because you could hear your heart beating doesn't mean that the foam was even remotely worthwhile for modal issues (which is the most essential and difficult aspect to tame regarding small acoustical spaces).

twas an anechoic chamber at a testing facility. Am pretty sure there were no modal issues or in fact, any other issues in the room. To all intents and purposes, the room was as dead as possible. By the way, the foam blocks were 150mm square, 600mm long, straight on 2 sides and curved on the othe 2, rotated 90 degrees to each other. Very speacial foam but indeed foam.

[hjames]

An anechoic chamber is used to test things (drivers, radiators, antennas, microphones) in the absence of reflected signal (be it audio, RF, microwave, whatever is under test). Measuring the driver's direct signal and its radiation patterns - Polar plots.

Very specific materials are used based on the characteristics and wavelengths to be tested.
not just any old foam, but materials known to have specific loss in the test range.
In short, its not just someone slapping cheap foam on the walls 'cause it looks the part.
Its an engineered space, with specific design goals. Its inert - dead.

Generally NOT a place to listen to music (or movies) for enjoyment.

[localhost127]

An anechoic chamber is used to test things (drivers, radiators, antennas, microphones) in the absence of reflected signal (be it audio, RF, microwave, whatever is under test). Measuring the driver's direct signal and its radiation patterns - Polar plots.

Very specific materials are used based on the characteristics and wavelengths to be tested.
not just any old foam, but materials known to have specific loss in the test range.
In short, its not just someone slapping cheap foam on the walls 'cause it looks the part.
Its an engineered space, with specific design goals. Its inert - dead.

Generally NOT a place to listen to music (or movies) for enjoyment.

precisely ! +1

foam is most certainly capable, but the issue is finding appropriate material that suits the design requirements --- and then also comparing the price of that to what would otherwise be used (porous rigid fibgerglass, mineral wool, etc).

good commentary: http://www.gearslutz.com/board/bass-...eal-worth.html

im still not seeing the measurements outlining the specific issues that need to be addressed (treated). why is the OP looking to apply solutions without knowing what the exact issues are? treatments should be tailored specifically to address measured problems within the room. also, prior measurements are needed -- because how else would you know whether the treatment is actually working as advertised (pre/post measurements to determine if the particular treatment applied has indeed solved the problem). is one looking to address issues in the specular or modal region? OP - please provide an ETC plot as well as a waterfall from 0-300hz. full frequency response isn't necessarily needed...the modal issues can be addressed via the waterfall plot (freq response 0-300hz + modal ringing detailed in the time domain), and the ETC will address all other issues in the freq response (to 20khz) -- via the time domain; as most of the issues in this area are from comb-filtering off first order reflections, etc. clean up the ETC and you will likely solve your specular freq response issues.

[Lee in Montreal]

more misinformation regarding rigid fibgerglass.

sigh,

Who's talking about rigid fiberglass?

I was mentionng fiberglass wool.

[macaroonie]

6 of them should do in a room your size? do cure what, exactly? you're recommending a solution without knowing specifically what the issues are he needs to address?

are the 6 panels to solve modal issues (wave), or specular early reflections?

Y'all gittin a bit to fancy there son.

Ashley lives in a small apartment and has limited resources. What he lacks in dosh and expertise he makes up for in enthusiasm. His room is more than likely somewhat splashy if you will and while the foam jobs that he was attracted to would do something what I suggested would most likely be cheaper and more versatile as a DIY solution towards his desired goal. We are talking less than a hundred bucks here chief , what do you charge for nipping out to do a modal analysis ?
Ash its about time you chimed in here fellah , what do you think ? You are the client after all.

Mac

BTW Mr Local host , I am not seeing any worthwhile practical suggestions coming from your quarter. $ 150 max

[Allanvh5150]

An anechoic chamber is used to test things (drivers, radiators, antennas, microphones) in the absence of reflected signal (be it audio, RF, microwave, whatever is under test). Measuring the driver's direct signal and its radiation patterns - Polar plots.

Very specific materials are used based on the characteristics and wavelengths to be tested.
not just any old foam, but materials known to have specific loss in the test range.
In short, its not just someone slapping cheap foam on the walls 'cause it looks the part.
Its an engineered space, with specific design goals. Its inert - dead.

Generally NOT a place to listen to music (or movies) for enjoyment.

My comment was made because someone said that foam was no good for controlling sound. I offered a situation that I have been in that has very very tight room parameters. The test facility is used for testing louspeakers, microphones, trucks, cars, F1 cars, you name it. plain and simple, foam works.

[Allanvh5150]

Y'all gittin a bit to fancy there son.

Ashley lives in a small apartment and has limited resources. What he lacks in dosh and expertise he makes up for in enthusiasm. His room is more than likely somewhat splashy if you will and while the foam jobs that he was attracted to would do something what I suggested would most likely be cheaper and more versatile as a DIY solution towards his desired goal. We are talking less than a hundred bucks here chief , what do you charge for nipping out to do a modal analysis ?
Ash its about time you chimed in here fellah , what do you think ? You are the client after all.

Mac



BTW Mr Local host , I am not seeing any worthwhile practical suggestions coming from your quarter. $ 150 max

I fear that Ash is tired of being ridiculed by two LH members in particular, so he is keeping a low profile.....

[Allanvh5150]

An anechoic chamber is used to test things (drivers, radiators, antennas, microphones) in the absence of reflected signal (be it audio, RF, microwave, whatever is under test). Measuring the driver's direct signal and its radiation patterns - Polar plots.

Very specific materials are used based on the characteristics and wavelengths to be tested.
not just any old foam, but materials known to have specific loss in the test range.
In short, its not just someone slapping cheap foam on the walls 'cause it looks the part.
Its an engineered space, with specific design goals. Its inert - dead.

Generally NOT a place to listen to music (or movies) for enjoyment.

Not sure that I would test RF in an anechoic chamber with foam blocks on the wall. That would just be called a chamber.....

[hjames]

Not sure that I would test RF in an anechoic chamber with foam blocks on the wall. That would just be called a chamber.....

Not really.
I wrote that blurb on anechoic chambers accurately based on my knowledge of acoustics and RF,
to indicate that Anechoic chambers are used in many technology fileds - for instance - Audio, and RF.

With RF testing, yes, it is still called an anechoic chamber - RF bounces and scatters too, its just at different wavelengths,
so it would use foam and materials with damping characteristics at different (higher) frequencies. The idea and terms are still the same.

just for you, I looked it up - wikipedia says:

An anechoic chamber (an-echoic or non-echoing) is a room designed to stop reflections of either sound or electromagnetic waves. They are also insulated from exterior sources of noise. The combination of both aspects means they simulate a quiet open-space of infinite dimension, which is useful when exterior influences would otherwise give false results.

Something I found on the web ...

[hjames]

My comment was made because someone said that foam was no good for controlling sound. I offered a situation that I have been in that has very very tight room parameters. The test facility is used for testing louspeakers, microphones, trucks, cars, F1 cars, you name it. plain and simple, foam works.

Thats NOT what he said ... note my bolding in his original comment.

For what its worth that foam is not worth the candle , it's too thin. Proper acoustic foam tiles are 3-4" thick or greater and also quite dense.

So, very specific kinds of foam is used for sound damping - but any old eggcrate foam used as packing materials is not the engineered material typically used in an anechoic chamber.

With salvaged shipping materials - who knows what frequencies they would attenuate and by how much. Also, comments were made about how much sound control was needed, and at what frequency. Rather than make a really cool lookin' room, like you see in the movies, the conversation's approach was to measure and design, rather than just grab some discount foam and slap it up.

And again, the idea is (hopefully) not to make an echo-free dead (inert) audio space for home listening - that's a bad plan and would take away much of the joy of the home theatre room.

I don't mind discussing the technology with you, but you should do some research (google is your friend) if you want to build such a room.

[Allanvh5150]

Thats NOT what he said ... note my bolding in his original comment.



So, very specific kinds of foam is used for sound damping - but any old eggcrate foam used as packing materials is not the engineered material typically used in an anechoic chamber.

With salvaged shipping materials - who knows what frequencies they would attenuate and by how much. Also, comments were made about how much sound control was needed, and at what frequency. Rather than make a really cool lookin' room, like you see in the movies, the conversation's approach was to measure and design, rather than just grab some discount foam and slap it up.

And again, the idea is (hopefully) not to make an echo-free dead (inert) audio space for home listening - that's a bad plan and would take away much of the joy of the home theatre room.

I don't mind discussing the technology with you, but you should do some research (google is your friend) if you want to build such a room.

Well obviously my very limited intellect is you match for yours......

If you were so clever you would have known that I was reffering to the post by Akira where he said "Foam damping is the enemy of good acoustics" and added that Ash should try some moveable panels in his listening room. I ponted out and sighted an example where foam is the perfect absorber and can make a perfectly dead room. On the othe hand, yourself, seawolf and a few others only want to poke fun at and riddicule for some reason unknown to me. Maybe it is fun for you, who knows. You then proceeded to talk about RF....WTF.......how is the foam we are talking about going to have any effect on RF? An RF chamber would use RAM of some type but that is beside the point.

Someone asked some advice on foam and mostly he was met with BS from a handfull of.....well I dont really have words.

[hjames]

Well obviously my very limited intellect is no match for yours......

If you were so clever you would have known that I was referring to the post by Akira where he said "Foam damping is the enemy of good acoustics" and added that Ash should try some movable panels in his listening room.
I pointed out and cited an example where foam is the perfect absorber and can make a perfectly dead room.
On the other hand, yourself, seawolf and a few others only want to poke fun at and ridicule for some reason unknown to me.
Maybe it is fun for you, who knows? You then proceeded to talk about RF....WTF.......
how is the foam we are talking about going to have any effect on RF?
An RF chamber would use RAM of some type but that is beside the point.

Someone asked some advice on foam and mostly he was met with BS from a handful of.....well I don't really have words.

Well, you should have words - we are talking technical, you keep talking innuendo ...

I have no idea what you are actually thinking or trying to say -
all I can do is read the words you have typed and respond to them.
You oversimplify and get upset when we talk facts, then try to change it up again and again.

The whole discussion on putting foam on the walls should be about "What are you trying to do?" Its about engineering, its about science, its not about "looking the part".

You keep talking about your dead room, I and others here keep repeating you do not want a dead room to listen to movies and music in ... thus the discussion on Anechoic (Echo free) spaces.

Please, just read what we are actually posting rather than simply trying to start an argument

Continue on - I have to go off to work ...

[pos]

he said "Foam damping is the enemy of good acoustics"

it is. A dead room is not what Ashly should be looking for. There are plenty of good litterature on that topic.

[macaroonie]

it is. A dead room is not what Ashly should be looking for. There are plenty of good litterature on that topic.

Indeed there is , masses of it. Trouble is tghat the suject is pretty technical and the subject is potentially very confusing to a novice.
What Asley is looking for is a cost effective method of taming his room . What he is not needing is anechoic conditions nor anything aproaching it.

Here are some pics of Rockwool in frames and the implementation in a room. Hope it helps Mac