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Invisible Aplha©
Old 7th June 2012
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audiothings's Avatar

Invisible Aplha©

How do I delete a thread? I see that the question has already been asked, and I have contributed to it.
Old 7th June 2012
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avare's Avatar

Originally Posted by audiothings View Post
Hello to everybody and to Avare in particular.

Invisible Aplha© is an extremely interesting concept to me. A combination of LF and VLF absorption and isolation, while overcoming the caveats of a triple leaf construction. Control over the lowest critical octaves at a minimal space loss is always most interesting!

So, hopefully, with Avare's help we can find:

* The ways to calculate the best thickness/layers of drywall and the best air gaps for the specific needs of each room.

* Tips on the ways to complete the construction - including ceilings and floors - using Invisible Aplha© as the anchor point.

* Risks, caveats and pointers to ways that we may fall short of our expectations, and advice on how to ensure that our models/theories actually translate to working spaces.

If somebody writes a book explaining this stuff in a way that I can understand, I will pay $100 for it.

I know that enough internet searching, and buying, and reading, and understanding what is written in relevant books, can make my questions unnecessary. I hope that the people who are better than me will tolerate my impatience. I want to understand and apply this, without having to understand everything about the universe.

I am optimistic and I hope that we will introduce some efficient ways of building studios, into the public domain. Democracy seems to be the name of the game...

With thanks for all contributions,

EDIT: Andre, if this is not something you wish to share with the public, please let me know, and I will delete this post (if its possible).
Thank you for the post and it is perfectly fine to post about Invisible Alpha© .

You have lots of questions. Reveiwing what Invisible Alpha© is should clear up things considerably. The best I written to describe Invisible Alpha© is:

Invisible Alpha© is an adjective I coined to make the use of sound absorption of walls and other partitions as integral part of the room acoustics design sound more fancy, mysterious, high tech and a great marketing/sales tool.

There is nothing secret about it. You are building a room with 8' ceilings? Calculate the mass and airspace to resonate around 70 Hz. Done. The average person sees a ceiling, while you have great mode control.

Membrane absorbers with insulation fill, AKA walls, have an absorption curve that tapers off to one half the peak absorption at approximately half an octave above and below the resonant frequency. Using round figures 703 like material 4" thick has a useful absorption down to 125 HZ. Build the Invisible Alpha© membrane absorber, AKA wall, to resonate around 80 Hz and you have absorption down to 63 Hz.

The alpha of acoustics marketing,

It is
Old 31st January 2020
Lives for gear
Avare, it's a great thread, and a great approach. I have a question : let's take your example of a 8' ceiling. Let's say the room is a room within a room design.

By adding a membrane absorber in front of a MAM/MSM system, doesn't that lead to a triple leaf system? If it does, the acoustic is better but the soundproofing/insulation worst (because of the triple leaf sytem/double resonances)?

Looking forward to read you.
Old 1st February 2020
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avare's Avatar

Originally Posted by JayPee View Post
By adding a membrane absorber in front of a MAM/MSM system, doesn't that lead to a triple leaf system? If it does, the acoustic is better but the soundproofing/insulation worst (because of the triple leaf sytem/double resonances)?

Looking forward to read you.
Yes. So design the double layer to resonate at the desired frequency.
Old 17th February 2020
Will broadband absorption inside the room affect the resonant frequency of the wall? I calculated the mass and air space required to target the frequency modes within my space, but when I treat the back wall, corners and other reflection points with panels and traps I’m concerned this will either change the fMAM of the wall structure or that it may lessen the effectiveness.

Also, I have my room in the corner of a block wall basement, so only 3 of the surfaces will be drywall. Does low end membrane based absorption need to be symetrical in the space? I’m trying to determine if I need to place drywall along the last block wall to create some consistency in how the walls absorb/reflect sound.
Old 17th February 2020
Lives for gear
Avare will have a better answer but : you can add an air-gap between your wall which is part of your tuned system (the second Mass in your M-S-M) and your acoustic broadband absorption. So the Mass can still vibrate freely and such not be affected by the adding mass of the absorber.

Invisible Alpha for the low targeted frequency and broadband for above!

That's how I'd do!

Last edited by JayPee; 18th February 2020 at 08:43 AM..
Old 17th February 2020
Gear Addict

That resonating wall will still diminished sound reduction
Old 17th February 2020
Thanks for the responses! The air gap between the wall and broadband treatment sounds like a great idea. Basically, I want to treat the wall as the membrane in a membrane absorber and not allow insulation to touch the membrane, instead allowing the membrane to vibrate freely.
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