Best soundproofing wall design

[PerchPerkins35 (Nick parkin)]

Hi all!

I was wondering, if I was going to make walls that are 3-4” thick, what would be the best design to maximize soundproofing.

I was thinking having two layers of three-quarter inch ply on the outside and inside. Each sheet will be joined together at the edges with silicone adhesive, and screwed together at the top and bottom corners to ensure that the panels can vibrate somewhat freely as the silicone adhesive will dampen it and prevent the vibrations from transferring to other panels. In between the two panels I was thinking maybe doing some roxul safe n sound.

I will be using a watercooled spindle, (1500w) so I need to primarily focus on eliminating the frequencies generated by the bit cutting the wood. Does anybody know what specific frequencies the bit generates when it cuts Baltic Birch ply or MDF?

[Intohouse (Brandon)]

Quick tip, figure out which roxul you plan to purchase as they all come in different thicknesses. Based on what you wrote, you are going to consum 1.5" in just the two plywood/mdf panels. That only gives you 1.5" to 2.5". The Safe & Sound you refer to is 3" thick.

The thinest Roxul I have found is 1" thick. I was able to buy single sheets from Grainger https://www.grainger.com/product/ROXUL-1-in-x-48-in-x-24-in-Mineral-19NE76

[LiamN (Liam Newcombe)]

Might be worth having a read of this thread;

Building an enclosure

What you’re doing there is very similar to what people try to do with home music studios. Basically there’s two aspects to dealing with sound, Managing reflection and reverberation to manage the sound within a space Absorbing or isolating the sound energy to reduce the leakage out of the space. I can’t recommend this guy enough as a starting point to understand how this stuff works, he’s a real pro and talks sense not expensive products. I’m a bit of an audio nerd so I’ve already got some s…

Also, definitely worth watching this video, the guy knows what he’s on about;

- YouTube

[MadHatter]

I recommend looking into Homasote panels as well. Their process for mechanically isolating one side from the other is a good idea. I’ll link something later. I’m on mobile now.

EDIT: From this installation PDF, I used the “1- B) Staggered Stud Wall Construction” between my laundry room and TV room, and even with shoes and those dryer balls bouncing around in the dryer, I can hear them louder through the house if the pocket door is left open compared to what comes through the wall, and the open air distance is 4x greater.

So, maybe instead of two layers of plywood, you can use a layer of the Homasote sound barrier, like for the inside layer, and then sandwich the Roxul between it and the outer layer? Just throwing ideas out there. I used the Roxul rock wool in the remodel of my TV room, and that is a good call. That stuff is so much better for sound damping than the fiberglass that was in my walls. I live next to a hill, and with the double paned windows, Roxul rock wool and 5/8" sheetrock, the noise from the hill is gone - unless a window is open.