Floors
Brief
Great soundproofing starts with a solid foundation. Our live rooms and Control rooms are all built as a 'Room within a Room' design with no element directly coupled to the external frame of the building. This is the most effective means of isolation and is imperative to stop impact type vibrations from coming through. In the world of soundproofing there are 2 different types of sounds to address, 1) is Airborne sound or direct sound (Imagine this as the sound that comes out of your mouth as you sing, it travels through the air and is heard by your ears. This sound is the easiest to absorb as it looses energy the more mass it has to pass through and 2) is that of the vibration or Impact noise, The best example of this is foot falls, the noise from someone walking upstairs for example is transmitted to downstairs, (in most structures) via impact noise. These vibrations travel through the very frame of the building. It's also a major contributor to low frequencies getting through many Soundproof enclosures. As the bass frequencies from direct sound (from a bass amp for example) hit the walls a large portion is turned into mechanical energy as the walls vibrate and it's these vibrations are harder to absorb. But there are steps you can take to help substantially reduce this impact noise. The best way to achieve this is to isolate the soundproof enclosure from the external building frame and from any other room. At Qsound Studios our ceiling has special iso mount brackets that isolates it from the building frame but still helps to support the hanging weight, Our walls have another version of these iso clips between the Plasterboard layers and the frame and our floors also have an extremely effective method of isolation explained below.
The Floors
Let's talk about floors. For this example we will have a close look at the design on the Floating floors in Studio A which are a total bit of awesome tech hidden under your feet.
Between the Downstairs studios (Studio B) and Studio A Upstairs there is several thousands of dollars in materials and a tonne of weight (Literally). This is because before we built Studio A the space was a beautiful apartment and the floor was already Soundproofed. In 2018 we demolished the apartment and began constructing.
The original floors to the entire upstairs remain and are constructed as follows; Above the soundproof ceilings from studio B downstairs (Which are suspended from the Steel beams) there is a sealed cavity filled with 100kg/m3 Rockwool and air, after that cavity is 2 layers of Structafloor with Green glue in between the layers.
This is a typical Sound proof floor construction and it was effective in reducing a large portion of the sound, however, we wanted to achieve even more isolation when we turned the living spaces into what would become our primer Studio space. So we added another 2 massive floating floors, these floors are over the live room / iso booth and the Control room of our Studio A facility and are explained below.
Part 1 - Framing
Step one in floating floors is building the Framing, this frame will allow us to create a space under the floor which will be filled with Rock wool. In our Studio we have 110mm Rockwool in the 110mm floating floor cavity. You can make much smaller floors by using 50mm rock wool, but we wanted to control the sound as much as possible so we opted to go big or go home. Our frame is sitting on special U shaped rubber pucks to isolate the frame from the sub floor. As we talked about above, this significantly reduces, (almost completely) any impact based noise. you can see the frame and the rubber pucks in these images.
Cavity Soundproofing, Structafloor and Green Glue
After the frame is made we filled the gaps with Soundproof insulation. The colours are different in the 2 photos seen here due to the differences in product. In the Control room we used 110mm Bradford Soundscreen vs the live room in which we used 75mm 120kg/m3 rockwool. (The reason for this is below the Live room is a further decoupled floor layer or higher step up between (So there is actually 3 seperate floors on top of each other between the live room of Studio A and the downstairs ceilings) Because of this construction difference, the live room used a special custom order product. The specs of these 2 products was almost identical. The less dense but thicker Bradford soundscreen performs to the same levels across all frequencies as the less thick but more dense Rock Wool.
After all gaps are filled with the insulation, the first layer of Structafloor goes down. Sometimes called Yellow tongue flooring. The floor is glued and nailed to the frame. After this first layer goes down, Green Glue is used between the layers. Green glue is an amazing product that is more effective at reducing sound transfer than Mass loaded Vinyl. Green glue works by absorbing the vibration between the sandwiched sheets and allowing the 2 seperate sheets to vibrate at their own rates. When coupled with insulation in the cavity its extremely effective. But it's also wildly expensive, especially if you use the maximum amount for the best STC levels (As we did!)
Live room floor
Here you can clearly see the 2 Floating floors that exist Below the entire Studio A live room and the Anti-vibration pads. You can also see the 2 layers of structafloor.