The 1% Rule: A 1% opening will allow up to 50% of sound to pass through a wall, door, sound barrier, etc.
This rule comes into play most often when it comes to doors. Whether a regular door or a soundproof door, small openings almost always exist at the bottom, top and sides.
It is because of the 1% Rule that these openings around doors effectively cancel out any acoustic functionality.
For example, a 1/8″ opening around all four sides of an acoustic door(STC rating of 56) can significantly reduce the door’s STC rating (to as low as 21), which means the door is close to useless acoustically.
The picture below illustrates different size openings when it comes to airflow versus sound transmission. As you can see, a smaller opening reduces the amount of airflow, but does not reduce the amount of sound transmission.
So, how do we seal the door and defeat the 1% Rule? Read on…
Door Seal Kits – Include automatic door bottoms (see below) and high-grade neoprene door jams for the vertical sides and top of the door.
Automatic Door Bottoms– Our automatic door bottom sweeps utilize a concealed flat spring mechanism, which activates when the door is closed, lowering a neoprene seal insert against the floor or saddle.
Door Jamb Seals – This acoustical seal features our unique compress-o-matic design with a sound absorbing meoprene rubber gasket that compresses to form a tight seal as the door is closed.
Door Thresholds and Saddles – These acoustical door thresholds, commonly called saddles, feature a neoprene bulb fitted with a protruding rubber finger to help correct any misalignment in the door as it is closed.
Cam Lift Door Hinges – The can lifting action greatly improves the sealing characteristics along the door perimeter, lifting and lowering the door with the swing.
Meeting Stiles for Double Doors – Acoustical door astragals are designed to effectively seal off the air gaps that create sound leaks where the doors meet.
Click below to see a before and after video of an acoustic door seal kit.