Sound Deadening Testing – How It All Works, Weight Comparisons, & Coverage Comparisons
Important Information Before We Get Into The Data Please note, the full set of Constrained Layer Damper sound deadener product
    The Ford Bronco is a versatile and desirable vehicle, built to tackle trails and city streets alike. However, while its performance and style make it a standout choice for off-road enthusiasts, its interior noise levels leave much to be desired. Ford’s lack of attention to sound insulation has resulted in excessive wind noise, road noise, and vibrations that detract from the overall driving experience. For many owners, this has become a frustrating oversight in an otherwise capable and enjoyable vehicle.
    Fortunately, the solution lies in aftermarket sound deadening. By addressing key areas like the doors, floor, quarter panels, and hood, Bronco owners can significantly reduce unwanted noise, creating a quieter, more comfortable cabin. In this guide, we’ll explore practical steps to soundproof your Ford Bronco, improve its acoustic performance, and make every drive, whether on-road or off, a more enjoyable experience.
    The Ford Bronco’s off-road prowess and iconic design make it a sought-after vehicle, but its interior noise levels fall short of expectations. Excessive wind noise, road noise, and body vibrations are frequent complaints, highlighting a lack of attention to sound insulation during production. Addressing these shortcomings can significantly improve the Bronco’s cabin comfort, making it a more enjoyable vehicle for both daily commutes and adventures.
    While the Ford Bronco shines in off-road capability, its interior construction leaves much to be desired. The panels, trim pieces, and fittings often feel flimsy and poorly secured, leading to a symphony of rattles, vibrations, and resonances. These noises are especially evident on uneven roads or trails, where the cabin feels more like an echo chamber than a solid, refined space.
    To combat this, sound deadening materials can be applied strategically to reinforce and dampen these areas. CLD (Constrained Layer Damping) treatments can effectively absorb structural energy, reducing resonance and lending the interior a sense of sturdiness that Ford’s design overlooked. This upgrade doesn’t just reduce the overall noise, it adds a layer of refinement that the Bronco desperately needs.
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    The Bronco’s off-road-ready tires and suspension, while excellent for tackling trails, amplify road noise when driving on paved surfaces. The hum or roar of tires can dominate the cabin, making conversations or listening to music a challenge.
    Sound deadening and sound absorbing materials can be installed in the wheel wells and floor areas to mitigate this noise. By reducing the transmission of road vibrations into the cabin, you’ll notice a significant improvement in cabin quietness, without compromising the Bronco’s off-road capabilities.
    The Bronco’s boxy shape and removable roof panels are part of its charm, but they also contribute to excessive wind noise, especially at highway speeds. Poor sealing around doors, windows, and roof edges exacerbates the issue, creating a constant whoosh that fatigues drivers over long trips.
    Improving wind noise requires attention to seals and gaps. Enhanced weather-stripping and strategic use of acoustic foam or barrier materials can help seal leaks and block airflow paths, leading to a quieter cabin without altering the vehicle’s rugged aesthetic. We did not get into this as the owner wasn’t sure if he was going to swap the roof for an aftermarket one or not at the time of installation.
Before we get into this, it is important to note that every situation is different, every application is different, and everyone’s needs/wants are different. For our specific clients goals, which was to reduce outside road/tire noise, wind noise, and drone without doing anything to the roof. If you would like guidance that is specific to your situation, please do not hesitate to reach out to us.
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    With the problem areas identified, it was time to dive into the installation process, beginning with the doors. The doors were a significant source of noise due to their construction and lack of proper insulation, so they were a low hanging fruit for me to address.
    First, I removed the interior door panels to access the inner workings of the doors. My initial step was to address the space between the outer door skin and the crash bar. I applied ResoNix Butyl Rope in this gap to use the crash bar as a stabilizer for the outer door skin. The Butyl Rope acts as a flexible yet firm filler that prevents resonance, which is a common source of unwanted noise.
    Next, I focused on the outer door skin itself. To reduce resonance and dampen vibrations, I applied ResoNix CLD Squares directly onto the metal surface of the outer door skin. These CLD Squares are highly effective in minimizing panel resonance by converting vibrational energy into negligible heat, effectively quieting the metal surfaces. Ensuring full adhesion, I rolled each square firmly onto the cleaned metal with the ResoNix Roller to maximize their effectiveness.
    Over the CLD Squares on the outer door skin, I installed ResoNix Guardian. This specialized sound absorber/noise barrier composite product is designed to absorb and block airborne sound waves from entering the cabin through the doors. By layering the Guardian over the CLD-treated outer door skin, we created a comprehensive barrier and sound absorber system that blocks and absorbs external noise, significantly improving the door’s acoustic performance.
    I decided to leave the inner door skin untouched, as it was not a primary contributor to the noise issues. This allowed me to focus more attention on the door panel itself, which also played a role in transmitting noise into the cabin.
    Turning to the interior side of the door panel, I addressed the potential for buzzes and rattles caused by overlapping plastic seams. These seams can vibrate against each other, especially when driving over rough terrain, creating annoying sounds inside the cabin. To mitigate this, I used ResoNix Butyl Rope to fill and cushion all the overlapping plastic seams. The pliable nature of the Butyl Rope makes it ideal for this purpose, as it conforms to the irregular shapes of the seams and stays in place over time.
    To reduce resonance and vibration of the door panel itself, I applied ResoNix CLD Squares to the back of the plastic door panels. Even plastic components can resonate and transmit vibrations as audible acoustic energy, so treating them with CLD helps to dampen any potential noise sources. The CLD Squares were carefully cut and placed on flat areas of the plastic panels, avoiding any clips or attachment points to ensure a proper fit when reassembling the doors.
    Finally, I enhanced the sound absorption capabilities of the door panels and allowed the plastic door panel to be decoupled from the metal inner door skin by installing a combination of ResoNix Fiber Mat in both 0.5-inch and 1-inch thicknesses (depending on how much room was available in a given location on the back of the door panel) over the CLD on the back of the door panels. The Fiber Mat is an exceptional sound absorber, designed to reduce airborne noise by dissipating sound waves within its fibrous structure. By layering the Fiber Mat over the CLD-treated door panels, we added an extra level of sound absorption, effectively reducing any remaining noise that could penetrate the cabin through the doors.
    With the doors fully treated, I reassembled the door panels, taking care to ensure that all components fit securely and that the added materials did not interfere with any mechanical functions. The result was immediately noticeable. The doors felt more solid when closed, and the intrusive noises that were once prominent had been significantly reduced. The combination of vibration damping, noise blocking, and sound absorption created a much quieter and more comfortable environment inside the Bronco.
    This meticulous approach to treating the doors set the foundation for the rest of the installation. By addressing each potential noise source systematically, we were able to enhance the overall driving experience without compromising the Bronco’s rugged appeal.
    Next on my list was the floor. Removing the seats, rubber floor mats, and various side trim was predictably straightforward on the Bronco, making this part of the process relatively hassle-free. With the interior stripped down to the bare metal, I had full access to tackle the resonance of the floor and noise infiltrating from beneath the vehicle.
    I began by applying ResoNix CLD Squares directly onto the exposed metal floor. This step was crucial in reducing the floor’s tendency to resonate with vibrations from the road and drivetrain. The CLD Squares work by dampening these vibrations, converting them into negligible heat, and preventing them from amplifying inside the cabin. They essentially prevent the surface that they are adhered to from acting as a speaker.
    Once the CLD Squares were securely in place, I added a layer of ResoNix Fiber Mat 0.5″ over them. The Fiber Mat excels at absorbing airborne noise that penetrates through the floor from the road below. By combining the CLD Squares with the Fiber Mat, I created a two-tiered defense against both structural vibrations and airborne noise, significantly enhancing the overall quietness of the cabin.
    Throughout the installation, I took careful precautions to avoid interfering with the vehicle’s vital components. I was mindful of wire harnesses, mounting points, and other important elements, ensuring that their functions weren’t impeded. This attention to detail preserved the integrity of the Bronco’s systems while maximizing the effectiveness of the sound treatment.
    Reassembling the interior was as straightforward as disassembly. The seats and trim pieces went back into place seamlessly, and the added materials didn’t cause any fitment issues. The floor mats did obviously have a much tighter fit, but in the end, there was no issue. The transformation was immediately noticeable. The cabin felt more insulated, and the intrusive road noise from below was significantly diminished, contributing to a much more comfortable driving experience.
Tip: Use the supplied extra wax paper to make templates to make your shapes.
    Next up were the interior quarter panels. In the Bronco, these panels are essentially large hollow cavities that unfortunately act like echo chambers for noise. Inside these cavities, I had access to the outer body panels, which are quite resonant due to their thin construction and lack of insulation.
    To tackle this issue, I began by applying ResoNix CLD Squares directly onto the accessible areas of the outer body panels within the cavities. This step was crucial in reducing resonance and preventing these panels from amplifying external noises. The CLD Squares dampen vibrations by converting them into negligible heat, effectively silencing the metal surfaces that would otherwise act like speakers.
    After treating the outer panels, I filled the entire cavity with 1-inch ResoNix Fiber Mat. This material excels at absorbing airborne noise, and by filling the cavity, I significantly reduced the amount of sound entering through the quarter panels. More importantly, this also addressed noise from the wheel wells located just below, which are notorious for transmitting tire and road noise into the cabin.
    On the interior trim of the quarter panels, I applied ResoNix CLD Squares (not pictured) to dampen any vibrations and resonance within the plastic components themselves. Even plastic panels can contribute to noise if they resonate or vibrate, so treating them ensures a comprehensive approach to sound deadening. Then, I added a layer of 1-inch ResoNix Fiber Mat to further enhance sound absorption. This combination not only reduces noise but also helps decouple the trim panel from the vehicle’s structure, preventing any potential rattles or buzzes.
    With the quarter panels fully treated, I carefully reassembled them, making sure that the added materials didn’t interfere with the fit or function of any components. The transformation was immediate. The cabin became noticeably quieter, and the intrusive noises from the rear of the vehicle were significantly diminished.
    By systematically addressing these large hollow cavities, I eliminated a major source of unwanted noise, further enhancing the overall driving experience in the Bronco. This step, combined with the treatments applied to the doors and floor, contributed to a much more comfortable and enjoyable ride.
    With the doors, floor, and interior quarter panels thoroughly treated, it was time to turn my attention to the wheel wells on the exterior of the vehicle. These areas are significant contributors to road noise, tire hum, and the sounds of debris hitting the undercarriage, especially in a vehicle like the Bronco with its aggressive off-road tires.
    Starting with the metal body around the wheel wells, I applied ResoNix CLD Squares directly onto the exposed metal surfaces. This application was essential in reducing resonance and preventing the metal panels from amplifying resonance into the cabin. By dampening the vibration of these panels, the CLD Squares effectively stop the panels from acting like large speakers broadcasting unwanted noise.
    Over the CLD Squares, I installed ResoNix Fiber Mat, which absorbs airborne noise. By combining the CLD Squares with the Fiber Mat, I created a robust defense against both structural vibrations and airborne noise infiltrating the cabin from the wheel wells.
    Moving to the front of the vehicle, the fender liners presented a unique challenge. Made from a felt material, these liners do not allow CLD products to adhere properly. However, they are still a significant pathway for noise. To address this, I treated the front fender liners exclusively with ResoNix Fiber Mat. The Fiber Mat was carefully applied to the inner side of the fender liners, enhancing their sound-absorbing capabilities without the need for CLD.
    The rear fender liners were constructed out of a traditional plastic material, allowing for a different approach. Since the rear liners are essentially decoupled from the cabin, applying mass to them can effectively block noise. Normally, CLD is not considered a noise barrier, but in this specific case, it acts as one due to the liners’ separation from the vehicle’s interior. I applied ResoNix CLD Squares to the rear fender liners to add mass, thereby blocking noise transmission through them. Over the CLD, I added ResoNix Fiber Mat to further absorb any remaining airborne noise.
    By addressing both the metal body around the wheel wells and the fender liners themselves, I tackled the issue of road and tire noise from multiple angles. This comprehensive treatment significantly reduced the sounds of the tires on the road, debris striking the undercarriage, and general road noise that had previously permeated the cabin.
    With the wheel wells and fender liners properly treated, I reassembled all components, ensuring that everything fit correctly and that the added materials did not interfere with wheel clearance or suspension movement. The difference was immediately apparent during the test drive. The intrusive noises from the road and tires were substantially diminished, making for a much quieter and more pleasant driving experience.
    This step was crucial in rounding out the sound treatment process. By systematically addressing each area where noise could infiltrate the cabin, I was able to transform the Bronco into a vehicle that maintains its rugged capabilities while providing a level of interior comfort and quietness that far exceeds the factory setup.
Unfortunately, I forgot to take photos of the fender liners and the treatment that I had applied to them.Â
    Lastly, I turned my attention to the hood. Treating the hood can significantly absorb and reduce the noise generated by the engine, making a noticeable difference in cabin quietness. The process began with removing the OEM hood liner material, which was straightforward and allowed full access to the underside of the hood.
    I started by applying ResoNix CLD Squares directly onto the underside of the hood. This step was crucial for a couple of reasons. First, it helped reduce the resonance of the hood itself, preventing it from vibrating and amplifying engine noises. Second, in this particular case, the hood is essentially decoupled from the cabin, allowing the CLD Squares to act as a noise barrier as well. While it’s rare for CLD to function as a noise barrier, the hood’s separation from the cabin structure makes it effective here.
    With the CLD Squares securely in place, I moved on to enhancing the sound absorption capabilities. I treated the back of the OEM hood liner with ResoNix Fiber Mat. By adding the Fiber Mat to the hood liner, we significantly improved its ability to absorb airborne engine noise before it reaches the cabin. The fibrous structure of the Fiber Mat dissipates sound waves, reducing the overall noise level generated by the engine.
    Reinstalling the treated hood liner was straightforward, and the added materials didn’t interfere with the fit or function of the hood. The combination of damping the hood’s vibrations and enhancing its sound absorption capabilities resulted in a noticeable decrease in engine noise within the cabin.
    By systematically addressing the hood, we tackled one of the last major sources of unwanted noise. The cumulative effect of treating the doors, floor, quarter panels, wheel wells, and hood transformed the Bronco’s interior into a much quieter and more comfortable space. This comprehensive approach ensures that the vehicle retains its rugged performance while providing a significantly enhanced driving experience.
As mentioned earlier, if you would like specific guidance for your installation, please do not hesitate to call or email us at any time. Thank you!
Important Information Before We Get Into The Data Please note, the full set of Constrained Layer Damper sound deadener product
Miguel Rios of Waveform Tuning, A Travelling Car Audio DSP Tuning Service Demo Car: Grey, the Mazda CX-50 Â Â
ResoNix Sound Solutions is a company with a specialty in high-end car audio and automotive sound treatment that offers top quality products and services that provide superior performance in their respective categories. No gimmicks, no baseless claims, no nonsense. Constrained layer dampers, sound absorbers, decouplers, noise barriers, and car audio DSP tuning and consultation services are part of our line-up with a focus on data-backed, solutions-based products developed by professional enthusiasts, for enthusiasts.
