Acoustic treatment


I want to build my own bass traps and was wondering if there are any other alternatives to fiberglass and rokwool. Foam is not a consideration as I don't believe it has the necessary qualities for absorption. I have heard of cotton batting, does anyone have experience with this material. The idea of fiberglass makes me itch just thinking about it, but I'm resigned to using it or rokwool if that's all I have.  Please make suggestions and let me know your experiences.

Thanks
Mike
zardozmike
Huh? Didn’t you 🔙 post the equation last week? We already covered this last week. Does that refresh your memory?

Here’s a question for you - how can I hear a low frequency sound through ear buds if the wavelength is 32 feet?

Another question fir you - How can several tiny little bowls with diameters of 1” affect very low frequencies in the room?

Another question - How can a Schumann frequency generator affect the sound in the room when the wavelength of the Schumann frequency 7.8 Hz is 25,000 miles?
I done some long time ago with big Kotex pad ( feminine hygiene pad ) and this was the best really I tack it all around the inside and for the rest loose part I put dacron a kind of wadding or you could go like Radford speaker in is opinion he put  some real wool carded it was the best thing I use to have Radford speaker was very good in the time 1972 I gave it to my son still good redone the crossover ..........excuse my english I am french 
Shear waves in solids are what change the air molecules that come in contact with various solid materials. The acoustic wave that is generated from this interaction returns to the solid surface creating more shear and then more acoustic energy is generated off the solid surface.  This process happens all over again..not a giga buddy UFO magnetic field. . Just many many touches between shear waves and acoustic waves. Never dissipated just converted into acoustic waves..and then shear until the wave diminishes into or between 2 or more surfaces.

The material tension changes the reactivity of the surface ..This tension also changes the shape of the surface and adjusts the resonance point of the surface changing where the shear is most reactive. A strike away from  the Resonant Point will give a drum a different sound than a strike right on top of the Resonant Point. Maximum energy transmission is when a wall surface resonant point is found and when a acoustic resonator is placed on that surface point. Tension will adjust the shear wave transmission between those 2 surfaces now touching at that point. The resulting shear wave transmission will follow a shape say a tiny bowl and the air molecules that are around that shape take on those patterns and are excited ..and so you have a shape and a material and together they generate a new sound. Change anyone of those.. add a new boundary such as a piece of tonewood and then add a jewel or 3 you will have another new sound..because they are all attached they will generate multiple shear wave patterns and then new multiple acoustic waves and patterns....Tom

PS.. Eighth Nerve was Room Tune when they split to Nashville..

Mike you should look into the purchase of long hair sheeps wool. I have purchased this material in large volume from a vendor in Michigan years ago. It is a wonderful material to work with and is safe to use in your home.


 



























@karl77, I use those pads to damp the high-frequency ring of my drum heads. ;-) Makes 'em sound like Levon Helm's, low and "thumpy".
Thanks to Geoff remarks about Helmhotz resonator... I completed the installation of 8 carafes and varied bottles with different aperture with different tubes of my own making inside, and different level of water to discover the right one and I must say the effects are astounding on all counts...And at no cost...All of you read about that and think,it is not necessary to pay anything, very simple to inplement if you try and trust your ears...