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doobooloo, I am in the middle of a project precisely along the lines you have contemplated. I am using the canonical blocking and absorbing materials placed inside a form-fitted cover that matches the shape and color of the back space of the GT3. The finished parts will resemble cushions that can be easily inserted and removed from the back space of a GT3. My buddy's wife is stitching the removable covers for the acoustical innards. I should have the complete set of "cushions" in a month or so. I will report back with photos of the project and comment on how successful it was.
I would also be interested in the group buy. Since I did not to far with coco mats. But to honest the noise stopped bothering me 😉.
I would also be interested in the group buy. Since I did not to far with coco mats. But to honest the noise stopped bothering me 😉.
If you are at this point Motts…I am certain that if you put PS4 rubber on your car..you will be pleasantly surprised at the outcome for such a simple fix. I started out like you looking for mats or even putting Dynamat or equal in the car but was apprehensive …so swapped out the rubber and WOW, the impact on my whine sensitive ears was remarkable. If somebody produced a set of mats as described in this thread I would consider for sure - but my tire swap last year had me moving on to other irritants such as the ride height of my wife’s Targa…
If you are at this point Motts…I am certain that if you put PS4 rubber on your car..you will be pleasantly surprised at the outcome for such a simple fix. I started out like you looking for mats or even putting Dynamat or equal in the car but was apprehensive …so swapped out the rubber and WOW, the impact on my whine sensitive ears was remarkable. If somebody produced a set of mats as described in this thread I would consider for sure - but my tire swap last year had me moving on to other irritants such as the ride height of my wife’s Targa…
Couldn’t agree more! But if someone would make a throw over for the back shelf I would definitely buy it.
So for me, it’s not about the road noise, but more about the weird resonance in the cabin that seems to create a peak at around 4k rpm that, coupled with the nonlinear behavior of exhaust valves opening around that context, causes a bit of ear fatigue after drives and ringing in the ears after drives longer than 1/2hr. So my goal is to soften that by absorbing some of the sound energy reflecting around in that cavernous rear which also happens to be the source of all that noise too.
So recently I ordered a 4’x8’ sound absorbing sheet meant to be hung on walls from Audimute, figuring this folded in half would fit nicely in the rear. I also had some 2” thick 2’x4’ sound absorbing panels from Soundproofcow lying around, so I cut a ~3ft section to fit the rear shelf and sandwiched it inside the folded Audimute blanket and all of this fits rather nicely, see photo below. The remaining blanket forms a double layer curtain over the rear seat cutouts, I could technically cut out and put another 2” thick panel under there too but think this is a cleaner solution for now.
I haven’t gotten a chance to road test this yet but seems pretty promising from some brief revs in the garage. Will post some feedback tomorrow once I’ve had some time with it on the road.
Anyway I think this came out looking much cleaner than I had expected!
Some of these workarounds are a lot of effort for a car that is known to be raw and that's one of the selling points. I guess if the GT3 is your daily and only car but it seems to defeat the purpose of the car. I could see putting PS4S tires on since most of us will never track our GT3 Touring but more than that seems a bit much. There are better cars if you want a quieter sports car. Porsche even has some to choose from.
Some of these workarounds are a lot of effort for a car that is known to be raw and that's one of the selling points. I guess if the GT3 is your daily and only car but it seems to defeat the purpose of the car. I could see putting PS4S tires on since most of us will never track our GT3 Touring but more than that seems a bit much. There are better cars if you want a quieter sports car. Porsche even has some to choose from.
Oh I love the rawness of the car and even after going through numerous other cars I keep coming back to it… I’m on my 3rd Touring! But I also love my hearing and when they ring after every spirited drive it’s a problem. My goal with this is not to turn it into a Camry - just tone down some of the peaks and cabin resonance. My Speedster with its blocked off rear, soft fabric roof, and revised geometry (lower A pillar and roof) produce a far more pleasant and less peaky tones throughout the rev range, and it is definitely not a quieter car vs the Touring!
Do you guys ever use the function on the iWatch that shows you how much noise you are exposed to in relation to what is safe and not safe...??? I haven't been around anything where I can quantify before/after but that would be interesting if anyone measured before/after and what levels are read for stock tourings.
Do you guys ever use the function on the iWatch that shows you how much noise you are exposed to in relation to what is safe and not safe...??? I haven't been around anything where I can quantify before/after but that would be interesting if anyone measured before/after and what levels are read for stock tourings.
Did not know this was a feature. I’d love to try it out. Sadly I recently sold my Apple Watch from lack of use. All I’ve been going off is - “if my ears ring then it’s bad” which unfortunately also may signal damage has already been done.
To be fair the GT3 isn’t the only car that caused ringing in stock form - the Lotus Elise also had this problem for me. Speedster too but the threshold is a bit higher for the Speedy vs Touring.
Do you guys ever use the function on the iWatch that shows you how much noise you are exposed to in relation to what is safe and not safe...??? I haven't been around anything where I can quantify before/after but that would be interesting if anyone measured before/after and what levels are read for stock tourings.
There’s gotta be small decibel meters that can be clipped on the vents or something. I’m going to look into this!
I have an update, and I have included two photos to whet your appetite.
The first photo is of the completed but unfinished sound-blocking and sound-absorbing panels—they are sitting upside down. Using templates that I made, I cut the materials to size and test fit them. Then I used double-sided tape to adhere the layers together. The bottom layer is Luxury Liner Pro, purchased from Second Skin Audio. It is a 1.25 lb./sq. ft. mass loaded vinyl product with a bottom layer of closed-cell foam. It is the sound blocking layer. On top of it is a 2 inch thick layer of Mega Zorbe Pro, which is a hydrophobic melamine foam panel. It is the sound absorbing layer. There are five complete panels—one for the back deck, one for the first short "waterfall" (this is what is pictured in the second photo), an inverted U-shaped panel that fits vertically over the hump, and two panels for the "seat bottoms."
The second photo shows the more-or-less finished rectangular waterfall panel in place. The panels were wrapped in batting before the covering fabric, a suede-like material, was applied. I purposely rubbed the cover fabric in several directions to show how the color changes. The back area of the GT3 around the hump is in the shade, and so looks darker than the back deck carpet and panel.
My GT3 has a wing on it, but I do not think that matters much given the nature of the project. I will pick up the finished panels on Sunday and report back with my observations and additional photos.
I have an update, and I have included two photos to whet your appetite.
The first photo is of the completed but unfinished sound-blocking and sound-absorbing panels—they are sitting upside down. Using templates that I made, I cut the materials to size and test fit them. Then I used double-sided tape to adhere the layers together. The bottom layer is Luxury Liner Pro, purchased from Second Skin Audio. It is a 1.25 lb./sq. ft. mass loaded vinyl product with a bottom layer of closed-cell foam. It is the sound blocking layer. On top of it is a 2 inch thick layer of Mega Zorbe Pro, which is a hydrophobic melamine foam panel. It is the sound absorbing layer. There are five complete panels—one for the back deck, one for the first short "waterfall" (this is what is pictured in the second photo), an inverted U-shaped panel that fits vertically over the hump, and two panels for the "seat bottoms."
The second photo shows the more-or-less finished rectangular waterfall panel in place. The panels were wrapped in batting before the covering fabric, a suede-like material, was applied. I purposely rubbed the cover fabric in several directions to show how the color changes. The back area of the GT3 around the hump is in the shade, and so looks darker than the back deck carpet and panel.
My GT3 has a wing on it, but I do not think that matters much given the nature of the project. I will pick up the finished panels on Sunday and report back with my observations and additional photos.
This is awesome. Looking fantastic and can’t wait to get more updates & impressions from you soon! Please keep us posted! Thanks!
Meantime, I’ve experimented with adding a layer of mass loaded vinyl to my very crude setup. 2lb noisegrabber mlv from soundproofingmlv.com cut to rough shape to cover the whole rear seat and shelf area. And then the layers of acoustic absorber panels mentioned previously laid on top.
Interestingly, the car is still quite loud. The peaks and resonances during hard drives and >4k rpm have been softened but still materially very loud and does not feel “domesticated” at all. Which is a good thing as long as my ears don’t ring after every drive and putting myself at risk of hearing loss. The biggest impact is in the lower rpm ranges while cruising. I wonder if a substantial portion of the mid range noise that we’re most sensitive in is transmitted via the whole chassis and through the doors, windows, etc - and the sound deadening in the rear chamber can only go so far to lessen those.
I’ve gotta go get a clip on sound meter to take some measurements soon…
This post will report on the effectiveness of the panels, both objectively and subjectively. I will include photographs of the installed panels in a separate post.
The finished panels are installed. I installed them before the end of January, but my friend was not happy with the fit and finish of one, so I returned it to her for a touch-up. Her touch-up did indeed improve the appearance. That explains why I am posting later than I had anticipated. I also took some sound measurements on my iPhone using the app SPLnFFT, both before and after the panels were installed. When I purchased the app some 6 years ago, it was considered among the best.
Regarding objective sound measurements, both before and after the panels were installed, I drove on the same roads with cruise control activated. My iPhone was lock in a mount in the same position each time—basically in front of the touchscreen. I used the fast Fourier transform setting to get readings in the frequency domain. At speeds 45 mph, 50 mph, and 55 mph, the was a reduction of 1 dB or so using the dB(A) weighting. The sound energy is largely below 300 Hz. My understanding is that blocking such low frequencies is difficult, hence I am not surprised by the seemingly modest reduction in dBs. At higher speeds, there was perhaps a bit large reduction in dBs.
As for my subjective assessment, I think the panels were a success. Despite what I wrote above, there is clearly less of that annoying mid- and higher-frequency white noise. An informal way I used to judge the difference was to look straight ahead while driving, and then rotate my head 90º to the right so that my right ear was between the bucket seats. Without the panels installed, that motion resulted in much more sound from the rear of the car (not surprisingly), whereas after the panels were in place, that action did not result in an increase in noise from the rear. The other benefit from the panels was that my Bose stereo sounds much more "clean." I think the sound absorbing property of the melamine foam made the interior less alive, which combined with the reduction in mid- and higher frequencies to yield cleaner sound. I also perceive that the bass is a bit more pronounced and cleaner too.
I now notice the noise from the tires and exhaust more. As suggested by others, swapping from MPSC2 to MPS4S tires will be beneficial to those seeking further reduction in noise. It seems most of the noise comes through the doors now, so working on them might be of value beyond what my project has achieved.
Now for the bad news. My friend is not interested in pursuing this project further—her arthritis prevents that. I also communicated with Kim at P1Designs, and she is not interested either. I have the templates that I made for the five pieces, so I could ship them to an interested party or someone could take them and pursue a small business opportunity for Rennlist.
In sum, this was a fun and effective little project. I will post photographs later today or tomorrow.
01-12-2022, 01:42 AM
