How Sound Deadening Materials Effectively Reduce Noise in Your Car

What is Sound Deadening Material?

Sound deadening material is a product that is applied inside automotive body panels to reduce unwanted noise and vibrations. There are a few main types of Sound Deadening Materials used in cars:

Mass Loaded Vinyl (MLV) - This is one of the most common sound deadeners. MLV has a thick, vinyl skin loaded with lead, tin, or other particulates that make it dense and heavy. This density helps MLV absorb sounds and vibrations in cars.

Dynamat - A popular brand of butyl rubber sound deadener. Dynamat sticks stickily to metal surfaces and also uses its density and composition to dampen sounds.

Closed-Cell Foam - Materials like polyurethane foam are effective because they are closed-cell, meaning their air pockets don't interconnect. This stops vibrations from moving through them.

What is Sound Deadening Material?

As mentioned, the three main types used are MLV, Dynamat, and closed-cell foam. MLV works because the lead particles make it very dense - its weight of approximately 4.5 lbs/sq ft gives it inertia to stop vibrations. Dynamat uses a specially formulated butyl rubber that remains flexible and tacky. This stickiness allows it to bond firmly to all vehicle surfaces while its mass works to damp resonant frequencies.

Closed Cell Foam varies in composition but most use polyurethane, which has an internal cellular structure that inhibits sound transmission. Air pockets are sealed off from each other within the material. When vibrations hit the surface, they cannot pass between the pockets so energy is absorbed instead of transmitted.

Several factors determine which product works best for a specific vehicle or installation area. MLV excels at stopping lower frequencies but is messier to install. Dynamat offers a simplified application with aggressive adhesives but is more expensive. Foams are easy to use but less dense materials.

Most professional installers recommend using multiple types layered together for ultimate noise reduction. For example, applying Dynamat to flat panels followed by MLV or foam on top of irregular surfaces like frames or inner doors. The varying densities provide sound blocking at multiple frequencies for quieter rides.

While MLV, Dynamat, and closed-cell foam are the most common, there are a few other product varieties available:

Liquidsound Deadners - These liquid formulas are sprayed or brushed onto surfaces to dampen vibrations. They use polymers and resin bases that set firm like Dynamat. Liquid sound claims ease of application over solid sheets.

Acoustic Mat - An open-cell air-filled material available in mat or tubular form. It absorbs noise through friction between the foam and air within pockets. Acoustic mats provide some noise blocking without the weight/thickness of other options.

Ceramic Sound Barrier - A relatively new product using micro-encapsulated ceramics within a flexible binder. Ceramics add mass without heavy particulate fillers. Ceramic sound barrier mat claims are vibration dampening, heat resistance, and lifetime effectiveness.

Drop Cloth - Thick tarps or woven drop cloths can block noise transmission when draped over areas. Their mass and flexible structure absorb vibrations and provide an air gap barrier against sheets. Best used underneath other deadening materials.

Installation tips for best results include using multiple product types combined (liquid, sheet, drop cloth layers), full coverage of target areas, smoothing out air bubbles, and applying heat after installation to further bond materials. Proper surface preparation like sanding or cleaning helps adhesion. Reapplication every 5-10 years refreshes the effects as materials can degrade over time.