What I've Learned and What You Need to Know

Imagine you are driving on the expressway and a very noisy truck is right next to you. Noise from the truck is coming at you through your vehicle's door and it's loud. There are three possible ways to stop the noise from reaching your ears.

The first thing you will notice is that the noise from the truck is making the door's sheet metal vibrate - essentially turning it into an unwanted speaker that is right next to you. Apply a vibration damper like CLD Tiles (Damplifier Pro) to stop the vibration. CLD Tiles have been designed to work with minimal panel coverage. That means you will need to do less work and the project will cost you less.

After you have stopped the sheet metal from vibrating you have two possible strategies left to deal with the noise that is still coming through the door. One possibility is to absorb the sound. Unfortunately, absorption isn't practical in a vehicle. The lower the frequency you need to absorb, the thicker the absorber needs to be. Road, engine and exhaust noise are deep (low frequency) sounds. To be effective, you would need an absorbent material between ten and seventy inches thick. And that's never going to happen.

Fortunately, the third option works perfectly in the space we have available. Block the noise. In exactly the same way the barrier wall of a recording room is blocking sound from entering the room next door and driving the neighbours crazy, you can do the same thing, on a much smaller scale, using Closed Cell Foam (Overkill Pro) and Mass Loaded Vinyl (Luxury Liner Pro).

It's really that simple. For years, we've been going about this all wrong - using layer after layer of "sound deadener" and getting poor results. Use the right tool for the job.

Defining Some Terms

Before we can get anywhere, we need to make sure we are talking about the same things. "Sound Deadener" is a vague term that describes a range of materials and techniques. It has traditionally been used when referring to vibration dampers - a specific class of products designed to control resonance in panels. I'll be referring to these products as vibration dampers.

When it comes to noise control we are concerned with engine, exhaust, tire in contact with road surface, and wind from entering our vehicle and from all of the other vehicles around us on the road. We may also be concerned with noise created by the music we play as it interacts with the vehicle around us. Some of the noise is transmitted directly through the structure of the car. Some of it travels through the air before it passes through the vehicle panels and glass on its way to our ears, often times exciting panel resonance that creates a secondary noise source.

The first step in any successful noise control or acoustic improvement project is minimizing panel resonance. It doesn;t really matter if the existing resonance is caused by the vibrations directly introduced by the engine, exhaust and suspension or if it is being driven by airborne sound. Resonating panels are important routes for transmitting and reinforcing noise.

Everything we are trying to do comes down to sound. Whether we are trying to quiet a vehicle, improve its ability to host a music system or both, it's all about sound and controlling what reaches our ears. Sound is almost devious in its behavior so we need to understand a little bit about how it moves around before we can control it. 


This is where vibration dampers come in. Your vehicle most likely came from the factory with at least some vibration damper applied. Unless yours is a luxury vehicle, or even if it is and you have added an aftermarket sound system that takes the vehicle beyond the original design specifications, you will want to add more vibration damper. OEM applications favor reducing weight and cutting cost beyond all else. In our adjective to quiet our vehicles, many of us took this too far in the opposite direction - applying multiple layers of vibration damper to every bit of sheet metal in the vehicle. I'll tell you something that no one else selling vibration dampers will - this is wasteful and counter-productive. Put images of shiny silver vehicle interiors out of your mind. When it comes to vibration dampers, anything more than 25% coverage is excessive. Beyond that, you are wasting time and money, making it difficult to refit trim panels and potentially making the vehicle more difficult to service in the future - you are using the wrong tool for the job.

Luxury Liner Pro on Floor Pan & Wheel Wells

Most exterior noises come from the road and your moving tires. Lowering your suspensions or having low profile tires only makes it worse. Not forgetting, as tires wear out, the noise gets louder. To overcome that, you will need a noise barrier to block out the sound coming into your car from the floor pan and most importantly wheel wells.

Good workmanship is hard to find these days and installing the materials correctly is the key to having best results. You can do it yourself but without the proper tools and technique you may not get the best results.

As you need to take out the seats, carpet and wheels for these installation, it's better to leave it to the experts.

Below are some pictures of how the floor pan and wheel wells are covered with Luxury Liner Pro on a noisy MPV. An installation done by Robin Audio Technik, one of our reliable and experienced installers.
(Note that the floor pan was already installed with another brand of Butyl Rubber to only stop vibrations.)


                              (LUXURY LINER PRO ON FLOOR PAN)

                    
                                 Luxury Liner Pro (Noise Barrier/ Insulator)

                          Guys at Robin Audio Technik installing Luxury Liner Pro

 

  

  

  

                                  Whole floor pan covered with Luxury Liner Pro

 

                              (LUXURY LINER PRO ON WHEEL WELLS)

                           Strong sprayed-on adhesive glue on the Luxury Liner Pro

                                    We use bolts as fasteners on top of strong
                                     sprayed adhesive glue for added strength.

 More pictures can be found in Second Skin Facebook page Second Skin (Singapore) Facebook Page