When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Unlike 1950’s production, contemporary automobiles incorporate much thinner sheet metal in body panels, door skins and frames.
When subjected to vibration and sound energy from within and without, modern car doors and body panels leave a lot to be desired from an occupant comfort standpoint
Exterior noise includes tire/road/engine/exhaust/wind noise/sound energy from our vehicles and others nearby (diesel trucks) that is dissipated through throughout the body structure and occupants.
Interior resonance is generated by our high wattage in cottage sound systems pounding away at thin sheet metal panels attempting to contain and attenuate this, along with noisy climate control ventilation systems.
This posting addresses noise and vibration prone doors of the LS400 (and would suggest this applies to all Lexus and O.E.M. car doors and body panels.
They all sound like tin cans when you knock on them) and provides installation images of applied products which significantly reducing ingress of exterior sound influences by dissipation/lowering of their natural frequency within the door structure while significantly improving the quality of mid-rang/ bass of our door mounted speakers.
Design Engineering, Inc. of Ohio, produces its range of Boom Mat brand sound dampening and sound isolating materials which are advertised to "reduce road noise, enhance audio performance and dampen vibrations."
Seemed worth investigating...
Here I focus on application of Boom Mat damping material which is offered 2mm and 4mm thicknesses in 12.5" X 12" and !2.5" X 24" in flexible viscoelastic polymer material with pressure sensitive adhesive and aluminum wear surface.
Total material application time of product, including removal and reassembly of interior panel on the front Driver's and passenger side front door is one hour for each door…
For those that have never removed Lexus door panels before, plan on accessing Lexus shop manual instructions for door pane removal (not hard, but you don't want to break anything) purchasing set of trim removal tools and replacement door panel plastic fastening clips and grommets in advance of the project. These age-harden, loosen with age and are prone to crack.. They are inexpensive and should be replaced while inside. Your Lexus parts guy can assist you in this regard. Do Not use non Toyota/Lexus parts!
For this project I selected 2mm material in 12.5" X 12" Boom Mat materials for covering 75% of the door skins, but not the frame and a 4mm thick 6" X 6" panel for the bottom middle inside of the door frame door panel facing inside the door cavity.
I used more material than the manufacturer recommended because the aluminum scrim/ decoupling was not as thick as I felt necessary to dissipate the vibration vs. simply lowering its frequency, which this material performs admirably.(dissipating vibration and lowering its frequency are two different approaches)
The speaker and plastic sheet access cover (held in place with butyl tape) was removed to allow access...plenty of room to work.
This plastic sheet is inadequate as a sound barrier of noise from inside the door; power window track and motor noise, lock solenoid outer door skin wind noise.
There is room for improvement with a loaded vinyl barrier and will address its application in a future project posting.
Two 8" X 12" sections were cut and affixed to the inner door skin panels above the horizontal crash bar to just below the window just below where the sill meets the window rubber weather strip.
Two 4" X 12" sections were applied directly below the crash bar, and finally two 4" X 12" sections were applied to the bottom inside door skin just below here the exterior door cladding fasteners protrude through the door skin.
The goal was not to cover over fasteners or access points.
Use rubbing alcohol on paper towel to clean the application areas...you will find the inside door panels of the LS400 are pretty clean however.
Mind the edges of the aluminum facing of the Boom Mat as it can be sharp.
Suggest wearing long sleeve shirt and gloves while applying material (although using gloves while placing material can make it harder to feel where you are at and prone to sticking to rubber gloves)
The adhesive is very tacky, so before removing the adhesive backing, be sure you first determine exactly how you are going to route the material through the door cavity for placement.
Others have opted to slather damping material on the door frame side that mates with the interior door panel.
I did not feel this was necessary and nor did I wish to interfere with Lexus fitment door panels precision fitment.
If you want to treat the door frame, do so from interior side (inside) of door.
Results exceeded expectations…
The sound system produced noticeably improved sound clarity (same song and volume setting) and the bass was less muddy and discerned improved clarity through mid-range.
While listening from the outside of the car, the sound was less discernible and the doors did not vibrate quite as much.
If sound energy cannot transmit from the door inside out, then it seems logical it can't as easily transmit from the outside in...
Knocking on the door skins felt solid… like knocking on a late 50’s Cadillac. (After treating one door went around and knocked on the other door and quite a difference.
Driving down the strip of test road which runs through a mile long underpass at the designated speed of 60 MPH there was a remarkable reduction in road noise in the doors area.
The material applied adds approximately 3.0 - 3.5 pounds of weight to each door which made it feel quite solid while opening and closing.
There is adequate room to use the 4mm Boom Mat material, however probably would improve stock sound system even more and reduce road noise further.
In this instance I can apply a second layer of 2mm Boom Mat if desired.
Treating the cars doors with a combination of sound damping, sound blocking, and sound absorbing materials provides a significant improvement to any car...even an Lexus.
Last edited by YODAONE; 08-14-18 at 07:59 PM.
Reason: califications
Can water soak into this stuff? If so its not the thing to do for longevity. And if its something that holds any sort of moisture, mold would love it too.
And that is one reason an OEM may not use something like that.
While considering material that was moisture tolerant, resistant to mold, unaffected by temperature cycling and overall proven long-term durability, observedToyota had already provided an answer...
A very similar butyl (tape) material as used in Boom Mat compound is used around the plastic cover for the door access panel.
After 17 years the bead of OEM butyl was still pliable, tacky without degration from mold, moisture or temperature extremes, so felt comfortable with selecting the Boom Mat material.
it has excellent adhesion characteristics and can be more fully pressed in place by a roller, or, as here, a deep well socket.
I had considered using high performance damping foam with a thick vinyl decupling layer to dissipate vibration and shock rather than simpky lowering the vibration frequency with Boom Mat, however that material supplier proved unreliable and could not get their act together.
Back in my stereo installer days we'd not only do the doors but pretty much everything else as well - trunk, floors, roof, rear deck, ect. Makes such a huge difference and people were willing to pay good $$ for the labor. Back then we used dynamat and if I recall they had three different types. One type was similar to the boom mat pictured above, which we usually used on floors and roofs since it helped shield heat. The other two types performed better but were much less pliable, did not have a metal layer and took alot more work to get worked around all the corners (lots of heat gun and rolling), and after breaking free the existing OEM stuff with dry ice.
Back in my stereo installer days we'd not only do the doors but pretty much everything else as well - trunk, floors, roof, rear deck, ect. Makes such a huge difference and people were willing to pay good $$ for the labor. Back then we used dynamat and if I recall they had three different types. One type was similar to the boom mat pictured above, which we usually used on floors and roofs since it helped shield heat. The other two types performed better but were much less pliable, did not have a metal layer and took alot more work to get worked around all the corners (lots of heat gun and rolling), and after breaking free the existing OEM stuff with dry ice.
The doors were selected as first project....significant improvement which does not require removing the whole interior.
For second phase am evaluating loaded vinyl sound barriers .080" thick and, sound absorbing material, for use between door panel and door frame... there is still room for improvement.
Once you quiet one thing another becomes more noticeable.
The floor is another problem area.
Am considering 1/8" or1/4" cork with overlay of 2mm Boom Mat.
The Boom Mat would work wonders for the trunk but overcome the gas struts. For lightweight solution am considering 1/4" cork with aluminum decoupling layer to dissipate vibration. Ditto for hood.
The roof is relatively quiet but am planning to apply dampening material at some point. Rain noise and perhaps wind rushing uptop at 70+ MPH. Can't have that.
The transition area between the rear quarter panel and roof is especially tinny and will apply 12" X 12" 4mm Boom Mat.
The front fenders are subjed to considerable tire/road noise and anicipate treating the vertical areas with 4mm Boom Matt. Have not determined best options for the fenderwells and secondary plastic liners. The factory uses special plastic spacers between fenderwell and plastic liner that dampens noise somewhat...
The tires that came with the car are noisy and am leaving them on until I have exhausted ways to attenuate noise elsewhere.
The rear deck panel will receive 2mm or 4mm Boom Mat atop and bottom provided there is room under the package tray.
Have not determined trestment for rear quarter panels and wheel wells.
Unlike 1950’s production, contemporary automobiles incorporate much thinner sheet metal in body panels, door skins and frames.
When subjected to vibration and sound energy from within and without, modern car doors and body panels leave a lot to be desired from an occupant comfort standpoint
Exterior noise includes tire/road/engine/exhaust/wind noise/sound energy from our vehicles and others nearby (diesel trucks) that is dissipated through throughout the body structure and occupants.
Interior resonance is generated by our high wattage in cottage sound systems pounding away at thin sheet metal panels attempting to contain and attenuate this, along with noisy climate control ventilation systems.
This posting addresses noise and vibration prone doors of the LS400 (and would suggest this applies to all Lexus and O.E.M. car doors and body panels.
They all sound like tin cans when you knock on them) and provides installation images of applied products which significantly reducing ingress of exterior sound influences by dissipation/lowering of their natural frequency within the door structure while significantly improving the quality of mid-rang/ bass of our door mounted speakers.
Design Engineering, Inc. of Ohio, produces its range of Boom Mat brand sound dampening and sound isolating materials which are advertised to "reduce road noise, enhance audio performance and dampen vibrations."
Seemed worth investigating...
Here I focus on application of Boom Mat damping material which is offered 2mm and 4mm thicknesses in 12.5" X 12" and !2.5" X 24" in flexible viscoelastic polymer material with pressure sensitive adhesive and aluminum wear surface.
Total material application time of product, including removal and reassembly of interior panel on the front Driver's and passenger side front door is one hour for each door…
For those that have never removed Lexus door panels before, plan on accessing Lexus shop manual instructions for door pane removal (not hard, but you don't want to break anything) purchasing set of trim removal tools and replacement door panel plastic fastening clips and grommets in advance of the project. These age-harden, loosen with age and are prone to crack.. They are inexpensive and should be replaced while inside. Your Lexus parts guy can assist you in this regard. Do Not use non Toyota/Lexus parts!
For this project I selected 2mm material in 12.5" X 12" Boom Mat materials for covering 75% of the door skins, but not the frame and a 4mm thick 6" X 6" panel for the bottom middle inside of the door frame door panel facing inside the door cavity.
I used more material than the manufacturer recommended because the aluminum scrim/ decoupling was not as thick as I felt necessary to dissipate the vibration vs. simply lowering its frequency, which this material performs admirably.(dissipating vibration and lowering its frequency are two different approaches)
The speaker and plastic sheet access cover (held in place with butyl tape) was removed to allow access...plenty of room to work.
This plastic sheet is inadequate as a sound barrier of noise from inside the door; power window track and motor noise, lock solenoid outer door skin wind noise.
There is room for improvement with a loaded vinyl barrier and will address its application in a future project posting.
Two 8" X 12" sections were cut and affixed to the inner door skin panels above the horizontal crash bar to just below the window just below where the sill meets the window rubber weather strip.
Two 4" X 12" sections were applied directly below the crash bar, and finally two 4" X 12" sections were applied to the bottom inside door skin just below here the exterior door cladding fasteners protrude through the door skin.
The goal was not to cover over fasteners or access points.
Use rubbing alcohol on paper towel to clean the application areas...you will find the inside door panels of the LS400 are pretty clean however.
Mind the edges of the aluminum facing of the Boom Mat as it can be sharp.
Suggest wearing long sleeve shirt and gloves while applying material (although using gloves while placing material can make it harder to feel where you are at and prone to sticking to rubber gloves)
The adhesive is very tacky, so before removing the adhesive backing, be sure you first determine exactly how you are going to route the material through the door cavity for placement.
Others have opted to slather damping material on the door frame side that mates with the interior door panel.
I did not feel this was necessary and nor did I wish to interfere with Lexus fitment door panels precision fitment.
If you want to treat the door frame, do so from interior side (inside) of door.
Results exceeded expectations…
The sound system produced noticeably improved sound clarity (same song and volume setting) and the bass was less muddy and discerned improved clarity through mid-range.
While listening from the outside of the car, the sound was less discernible and the doors did not vibrate quite as much.
If sound energy cannot transmit from the door inside out, then it seems logical it can't as easily transmit from the outside in...
Knocking on the door skins felt solid… like knocking on a late 50’s Cadillac. (After treating one door went around and knocked on the other door and quite a difference.
Driving down the strip of test road which runs through a mile long underpass at the designated speed of 60 MPH there was a remarkable reduction in road noise in the doors area.
The material applied adds approximately 3.0 - 3.5 pounds of weight to each door which made it feel quite solid while opening and closing.
There is adequate room to use the 4mm Boom Mat material, however probably would improve stock sound system even more and reduce road noise further.
In this instance I can apply a second layer of 2mm Boom Mat if desired.
Treating the cars doors with a combination of sound damping, sound blocking, and sound absorbing materials provides a significant improvement to any car...even an Lexus.
Rear door skin panels covered with 4mm Boom Mat.
Covered 70% of door panel...avoiding cladding fasteners and clips While rear speaker removed, added 4mm Boom Mat to back of speaker enclosure Coupled with Boom Mat material added to door, noticeable improvement in mid range and base response. ...and front of speaker enclosure
Added DEI 2 mm thickness BOOMMAT to front inner doors skins and 4 mm to rear inner door skins.
Front and rear speaker enclosures received 4 mm BOOM MAT and speaker performance improved appreciably.
The 4 mm BOOM MAT is the way to go for maximum results so am adding to the inner side of door frame that holds interior panel....
Hard to present images from inside door, but one of the outer side....and links to how Lexus is reducing NVH on newer LS460 LS600H
1998-2000 LS400 employ sound barriers behind rear seatback and dampening beneath the rear seat bottom.
OEM damping material applied to chassis sheet metal beneath the rear seat bottom does not offer full coverage. Both it and crossmember produce a very hollow tinny noise.
Later model LS employ much improved sound dampening under rear seat, so am applying the same solution to my 1999 LS400
Sheet metal below rear seat bottom amd crossmember are tinny, so treatment will yield NVH reduction.
4mm thick BOOM MAT cut to size using a paper template.
4mm Boom Matt with high tack pressure sensitive adhesive applied to foward facing areas of cross member The material is scored in two places (top of photo) allowing it to conform to surface.
Template and cut boom matt material for fit to chassis panel beneath seat bottom.Butyl damping material does not stink ((like asphalt-based materials)
Boom matt material applied. I took the liberty to remove and reapply the plastic nuts holding the original damping panels in place.
Adequatef room at crossmember berneath the carpet, and below seat bottom so seat fits perfectly.
Noticable reduction in exhaust and road noise along with less vibration.
Ls400 front fenders experience flutter underway due to lack of panel dampening .
Contemporary LS' use damping pads on interior side of fenders to alleviate this issue. (albeit not enough on thin sheet metal)
Knocking on the sides of the front fender one realizes very hollow metallic rapping noise...and not a solid thud consistent with a luxury automobike.
To remedy this, I determined to apply 4mm thick butyl based Boom Mat.to 70% interior of fender.
After acquiring shop manual instructions,, necessary removal of the plastic fender well is easy after removing tire....and recommend anyone doing so to acquire all new OEM hardware; plastic clips, screws and plastic grommets before proceeding..
A few images of the before and after.
Aquiring images in confines of fender proved daunting, but did my best.
Inside fender well with plastic wheel well liner removed... Absolutely no OEM damping material...
Another angle inside hollow area of fender
Top area of onner fender
BOOM MATT PAINTED.12.5\" X 24" X 4mm butyl damping material is cut into 6.25" strips for ease of fit and application
Image depicts thr inner fener area with Boom Mat applied. As in previous posts, use papet template. Installed this on a 95F day...cut product and leave in a cool area, otherwise it is too floppy.and installation becomes difficult without extra hands.Extra layer at rear of fender.
Another angle showing area above tire with applied material. Used one and a half sheets per fender..about 5 pounds.
Sounds like 1/4" steel now. .
Discernible noise reduction at 35 MPH.
Significantly less noise at 70 MPH
Am considering solutions for reducing tire noise reflecting off of plastic fender wells liners
Materials used in new Lexus wheel wells significantly improved.and actually absorbs sound.
Thanks yoda! I’ve been looking into doing this recently! I’ve been abusing the bass and it has caused HORRIBLE vibration in the doors, I’m definitely going to do this! Thanks!
Added DEI 2 mm thickness BOOMMAT to front inner doors skins and 4 mm to rear inner door skins.
Front and rear speaker enclosures received 4 mm BOOM MAT and speaker performance improved appreciably.
The 4 mm BOOM MAT is the way to go for maximum results so am adding to the inner side of door frame that holds interior panel....
Hard to present images from inside door, but one of the outer side....and links to how Lexus is reducing NVH on newer LS460 LS600H
The access hole cover is thin plastic and does little to block noise ..newer models employ solid plates.
Areas where Lexus has addressed NVH
Toyota employed a thin sheet of plastic as service hole cover, held in place with butyl rubber seal.
It is an excellent moisture barrier,, but poor sound barrier.
To remediate the situation, I employed DEI .080" thick barrier material with pressure sensitive adhesive.
The original plastic cover was removed and used as a template.
I elected to adhere the barrier to the OEM plastic in the half portion covering the major opening.
This was done to insure interior door panel fitment with close tolerance plastic clips onto door frame.
Double-sided butyl tape was aquiredf from McMaster-Carr to bridge the gaps and fortify the old tape ..worked well
Plastic access panel sheet removed and used as a template.
Material trimmed and cutout for yellow plastic screw grommet.
New barrier material applied to original.plastic barrier. The plastic/butyl permits easy removal..not sure the DEI barrier adhesive would allow multiple removal/reapplication cycles, so this combination offers best of both worlds.
Butyl tape being applied to bridge the gap at 4th side of access hole.
Installed.... Interior door panel refits like a glove. Will investigate using a full cover on the passenger side
Acquired new plastic access hole cover sheets for front doors from Lexus..
High quality plastic but does little to block door noise so employed DEI material (above) and applied over plastic OEM sheet to acomplsh task.
This go around used butyl tape and, foam from Lexus kit to reseal door lock linkage rods. Image of original plastic sheet at door linkage rods. OEM foam is held in place with pressure sensitive adhesive, but is expired.. Original sealing foam requires replacement New foam from Lexus kit Contents of Lexus kit includes foam with pressure sensitive adhesive and various thicknesses of felt sheets with pressure sensitive adhesive. Lexus kit P.N. Removed old foam with solvent and employed plastic spoon as scraper
Wax and grease remover fromn.Eastwood works well to soften old foam adhesive strip for removal After removal of foam seal, two holes appear...and foam, while a sound absorber, is not an appropriate sound barrier.. Lexus offers upgraded self adhesive hole covers. The DEI material would be ideal, but too thick to allow clearance for foam and linkage. OEM plugs applied. P.N. for new plastic access hole cover. Removing adhesive release paper from DEI barrier material after trimming Roll of butyl.tape acquired from McMaster-Carr Application of new foam seal DEI barrier material applied to new OEM plastic access hole cover sheet. (old sheet used as template) Fits well and significant reduction in window motor noise. (and wind/road noise underway) Fits behind interior door panel.
Good progress with the sound deadening efforts Yodaone. I once drove a 2010 Nissan pickup that was terribly noisy. I did similar boom mat installation to floors , doors and roof. The road noise in that car compelled me to get it done. I would like to do the same with my 1998 LS400, but its just quiet enough to make me put it off . Do you have any plans for additional layers of closed cell foam and mass loaded vinyl for the floors?
06-08-16, 04:46 PM
Sound dampening ls400 door panels and body
