Next project with my 2011 Range Rover L322 5.0: can I make it quieter inside, not just quieter but as silent as a Rolls-Royce? I have just started a full strip-down to install an extreme amount of sound isolation, from genuine recycled Rolls-Royce soundproofing sourced on eBay, through to covering the entire car in Silent Coat heavy sound-deadening mats and 6 mm Dodo Mat. This is not just about lining the body panels, but about wrapping every single surface, from the floors to the roof, including those scratchy plastics, in acoustic treatment.

For reference, this car is currently reading around 64–68 dB(A) at 55 mph and roughly 65–75 dB(A) at motorway speeds. By comparison, a Rolls‑Royce Ghost measures about 51.5 dB(A) at 55 mph, and the Phantom is similarly quiet at around 51–52 dB(A). My aim is to bring the Range Rover to within a couple of decibels of those Phantom‑level readings. It should be an interesting project.

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Will be following with interest.

all that extra weight will diminish your mpg

i think the FF is already fairly quite ,obviously not RR standard, and most noise is tyre/road noise..

good luck with your project  ... - .- -.




Y. O. L. O.
.

wow - that's some serious commitment - good luck

stan wrote:

all that extra weight will diminish your mpg

i think the FF is already fairly quite ,obviously not RR standard, and most noise is tyre/road noise..

good luck with your project

MPG

You are absolutely right about road and tyre noise being the primary source. This project is focused on isolating the cabin as effectively as possible, which means targeting specific frequency ranges. That is why I am using a combination of different materials, each selected to reduce particular frequencies and work together to deliver the best overall result. 2012 Range Rover L322 5.0 SC Autobiography – Sumatra Black
2010 Land Rover Freelander 2 HSE L359 – Grey
2015 Jeep Grand Cherokee Summit WK2 – Grey
1999 Mercedes E320 W210 – Silver

FINAL INSULATION PLAN – L322 - after much research......

✅ 1. FLOOR & FOOTWELLS
Products & Layers:
Silent Coat 2mm CLD
Stops: Structure-borne vibration from road and drivetrain.
6mm Dodo Mat (closed-cell foam)
Stops: Mid-to-high-frequency airborne noise, thermal transfer, trim buzz.
5mm MLV @ 10 kg/m² (full coverage)
Stops: Tyre roar, road hum, drivetrain boom, exhaust drone.
Rolls-Royce bitumen/jute insulation mats (flat sections)
Stops: Mid-frequency cabin echo, additional thermal mass.
Factory carpet
Factory removable floor mats

🚪 2. DOORS (Front and Rear)
Products & Layers:
Silent Coat 2mm CLD (inner door skin)
Stops: Panel vibration, resonance from road impacts.
6mm Dodo Mat (behind door card and/or inner skin)
Stops: High-frequency noise, air turbulence, door buzz.
2–3mm MLV @ 4–6 kg/m² (cut to fit inside cavity, adhered or floating)
Stops: Low-frequency road noise and wind intrusion without interfering with window function.
Rebuilt door card foam backing (Dodo Mat or CCF)
Stops: Trim rattle, plastic-on-plastic resonance.
Vapour barrier/membrane (resealed or replaced)
Stops: Air and moisture ingress.
Factory trim

🧱 3. FIREWALL / BULKHEAD (Behind Dash)
Products & Layers:
Silent Coat 2mm CLD (on exposed metal firewall)
Stops: Engine bay panel vibration and resonance.
6mm Dodo Mat (decoupler layer)
Stops: Thermal ingress and mid-frequency engine noise.
3–5mm MLV @ 6–10 kg/m² (depending on space, shaped around HVAC and fixings)
Stops: Engine drone, road noise through bulkhead.
Factory dashboard structure

🧳 4. BOOT FLOOR, SIDEWALLS, AND ARCHES
Products & Layers:
Silent Coat 2mm CLD
Stops: Vibration from diff, rear axle, exhaust.
6mm Dodo Mat
Stops: Plastic trim buzz, rear echo, heat from boot floor.
3–5mm MLV @ 6–10 kg/m²
Stops: Low-frequency noise from rear tyres and exhaust.
Rolls-Royce jute/bitumen insulation mats (flat boot floor only)
Stops: Additional mass and mid-frequency absorption.
Factory carpet and boot trim

☁️ 5. ROOF / HEADLINER
Products & Layers:
Silent Coat 2mm CLD (patch coverage)
Stops: Drumming from rain and roof vibration.
6mm Dodo Mat (full surface coverage)
Stops: Wind noise from above, thermal transfer.
2mm MLV @ 4 kg/m² (lightweight barrier foam, bonded if possible)
Stops: Airborne noise from wind and ambient traffic without adding dangerous overhead mass.
Factory headliner

🔊 6. TAILGATE (Upper & Lower)
Products & Layers:
Silent Coat 2mm CLD (on internal metal skins)
Stops: Tailgate vibration, resonance from road closure impact or subwoofer.
6mm Dodo Mat
Stops: Rear cavity resonance, trim buzz.
2–3mm MLV @ 4–6 kg/m² (shaped insert)
Stops: Low-frequency road noise entering through rear cavity.
Refitted trim panel

🚪 7. SECONDARY DOOR SEALS
EPDM bulb seal or tubing applied to door frame or pillar
Stops: Wind whistle, air leaks, improves acoustic compression and door shut quality.

⚙️ 8. OUTER WHEEL ARCH LINERS (EXTERNAL SIDE)
Knotted or bonded anti-vibration rubber matting
Stops: Tyre spray noise, grit impact, liner flex drumming.
Optional: thin CCF backing (if rebonding liners)
Stops: Amplified arch resonance, improves rear-end NVH.

📐 THICKNESS REFERENCE BY SECTION:
Floor/Footwells: Full-spec, 20–22mm total build height
Doors: 10–12mm (varies with trim depth and cavity space)
Firewall: 12–15mm (bulkhead-side only)
Boot: 15–20mm depending on contouring
Roof: Keep ≤10mm (safety-critical)
Tailgate: 10–12mm behind trim
Wheel arch liners (external): Add no more than 5mm total to avoid fit issues

🔧 SPECIFIC CHALLENGES TO OVERCOME
Weight Management
Full-cabin MLV and Rolls-Royce insulation will add 100–130 kg total, equivalent to two adult passengers.
Ensure suspension and ride height are not compromised long term.

Clearance in Tight Areas
Under-seat ducts, seat rails, and pedal box areas are tight.
Pre-cut MLV and foam precisely around mounting points and mechanisms to avoid binding or trim misalignment.

Adhesion and Layer Stability
Use high-temp contact adhesive or carpet tape for overhead and vertical surfaces (roof, doors, tailgate).
Reinforce edges with foil or gaffer tape to prevent curling over time.

Moisture Management
Ensure all vapour barriers are reinstalled or upgraded, particularly in doors and boot.
Use closed-cell materials where water exposure is possible. Avoid open-cell foams.

Access to Wiring and Fixings
Photograph and label all factory harnesses, grommets, and ECU covers before insulation goes in.
Cut access flaps in MLV layers if necessary, and seal with aluminium tape.

Reassembly Rattle Risk
All trim must be reinstalled under slightly more compression due to extra material.
Use felt tape or foam strip behind clips, panels, and fasteners to prevent new rattles forming.

Permanent Overhead Installations
MLV on the roof must be thin (2mm) and securely bonded. Avoid excess weight to prevent sag or safety hazard. 2012 Range Rover L322 5.0 SC Autobiography – Sumatra Black
2010 Land Rover Freelander 2 HSE L359 – Grey
2015 Jeep Grand Cherokee Summit WK2 – Grey
1999 Mercedes E320 W210 – Silver

Holy cow - that is going to take some time!

This is absolutely bonkers! I love it. 2006 L322 Vogue SE 4.2 S/C (no longer owned)
2008 L322 Vogue SE 4.2 S/C

Hi,

I looked at aftermarket Active Noise Cancellation systems some time back. Unfortunately the technology doesn't appear to be there yet unless it's build into the car's audio system from the outset.

But it is coming, some new cars have it now, but high end models generally, some others you can actually tailor it to hear what sort of sounds you want to hear, i.e. fake engine sound on electric cars etc.

Be interesting the next 5 years, I think it'll soon become mainstream, then you'll be able to dial it out without the weight penalties.

A. Fuji White / Jet 2012 4.4 TDV8 Westminster

This project is not stopping at just comparing sound levels.

By fluke I have learned something I never knew - I always thought it was the leather used in how Rolls-Royce achieve that constant scent inside their cabins, even decades later? And now I know! Total bonus!

I salvaged OEM Rolls-Royce SZ generation MLV with its original wool/jute backing. In that era, Rolls didn’t treat underfelt like ordinary carpet padding. It was over-engineered — a dense wool/jute blend weighing over 1,000 g/m², treated with lanolin, neatsfoot oil, and oak bark tannin, plus anti-fungal and mothproofing agents. This preserved the fibres for decades, made them moisture resistant, and gave that unmistakable warm, natural “coachbuilt” aroma. Even hidden layers were designed to contribute to the overall luxury experience.

Before fitting, I cleaned the jute thoroughly and re-treated it using my own recipe — a light mist of lanolin, neatsfoot oil, and oak bark tannin extract in warm distilled water, brushed in gently and left to dry for two days. The result is exactly as intended: the fibres are nourished and the scent has come back to life. They might not look like much but once installed and cut correctly and used in conjunction with the rest of the mass loaded vinyl layer and tapped correct it will be amazing….

I have not even installed them yet, but the smell is already incredible. Once the L322 cabin warms up, it will release the same subtle, rich scent you get when you step into a classic Rolls — a far cry from a standard l322 cabin

Noise levels will be dropping, and now by total fluke there will be an added bonus of that authentic Rolls-Royce atmosphere every time I get in.

Project is almost worth doing just for that benefit.