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noise reduction

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by sthom, Mar 18, 2015.

  1. sthom

    sthom Junior Member

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    I just purchased a 2012 Prius Two, not II, with 13,000 miles. I had test-driven Priuses before and even rented some for trips several hours long. I knew the ride was stiff, and noticed increased road noise on concrete freeways. However, I didn't realize how noisy and clunky the car would be on very bumpy city streets, esp. concrete. Yes, I did seek out the bumpiest streets around the dealers, but maybe it just didn't sink in--or maybe they weren't concrete. I'm interested in damping the sound, but need to determine what exactly is so noisy. The noises include 1) loud clunking or sharp thwacking on bumps like recessed sewer covers, seams; 2) then there is some low frequency rattling or reverberation related to going over noisy bumps, and then 3) the more superficial-souding rattles that sound like plastic in the interior. The thwacking and the lower pitched, or deeper noises are most bothersome to me since the thwacking is startling, and the deeper rattles seem to reverberate in the cabin and cause fluctuations in air pressure in a subtle way that bothers my ears. I might be totally off, but that is my impression. The superficial plastic rattles are only mildly irritating by comparison.
    I'm not a do-it-yourselfer but am interested in ideas for solving the more bothersome sounds; I want to know which sound can be lessened, which can't be, if the design or shape of the interior somehow increases the reverberation of certain frequencies (if anyone knows) --- and how to determine the source of the sounds, if possible.
    The road noise from tires doesn't seem to be a problem in comparison to those I described above. I have new tires from dealer. I might try decreasing the air pressure while keeping it within the recommended range, for a slightly softer ride, even though I know this will somewhat affect my gas mileage. Not sure if this would help the thwacking.
    I'm happy to try to provide more information or be more specific if that helps anyone. I appreciate input from people who have tackled similar problems. Thanks!
     
  2. Former Member 68813

    Former Member 68813 Senior Member

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    sounds (no pun intended) like you need a lexus. the next best solution (in the order of effectiveness) would be earplugs.
     
  3. bisco

    bisco cookie crumbler

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    tyres can be an issue. research quieter models like michelin energy saver a/s. and mke sure they are low rolling resistance if mpg's are important to you. all the best!(y)
     
  4. sthom

    sthom Junior Member

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    Thanks for the tip. I might look into different tires if those become an issue and take note of the ones you recommended. The larger concerns are the hard bumps and related reverberations, not constant road noise, as I associate with tires. Would different tires have any major effect on the noises I described and how the car responds to bumps at low speeds in the city? I just never thought of it.
     
  5. bisco

    bisco cookie crumbler

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    i think they can, but have no personal experience. whats your tyre pressure? some over inflate for mpgs, which makes for a hard ride. maybe you can look at shocks/springs?
     
  6. sthom

    sthom Junior Member

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    Ha--don't have a Lexus! I can't wear earplugs since I need to be able to hear what is happening around me on the streets, like sirens, etc. and I want to listen to music or the radio, or listen to the person riding with me. Thanks :)
     
  7. sthom

    sthom Junior Member

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    I will check tire pressure and try to reduce it without setting off the tire pressure alert to see what happens. That is an excellent idea. Do you know if shocks or springs are a common solution to Prius complaints? I know that my complaint isn't just isolated to my car. I've read reviews describing the same "thwacking" in Priuses that I've experienced. There is at least one independent hybrid mechanic that I know if in town, now that I think about it ( I just recently brought the car home from the dealer) and he might have some ideas of what's doable and what isn't. Thanks.
     
  8. My590L

    My590L Junior Member

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    You should be a QC Engineer for Toyota! You would get paid to solve all these squeak and rattle problems!;)

    I am not sure if the other trims have it, but on my 2014 Five, I noticed that there is this felt-like material that lines the wheel wells. I am thinking this is to reduce road noise from the tires.
     
  9. bisco

    bisco cookie crumbler

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    i have heard that changing the springs can make things worse, but the modders probably go stiffer. i don't know if there are softer springs available.
     
  10. sthom

    sthom Junior Member

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    Yeah--if only I could get paid to investigate why cars are so noisy! :)
    My tires are Bridgestone Ecopia EP20; it says they are "quiet ride" on Bridgestone website. Their "rolling noise" as I will call it, is minimal at freeway speeds on blacktop, but not on concrete, where there is noticeable difference. However, the most bothersome noise is in the city, at low speeds, on bumps. The more I listen as I get used to my car, I believe there is more noise from things rattling than I previously thought, and it's impossible to pinpoint where it's coming from as the driver. I suspect it comes from a variety of places. I've seen posts on damping the doors. I do notice that certain doors sound more hollow that others when I close them.
    And by modifying the tire pressure, I can decrease the impact causing reverberation and rattling.
    I'll check out the wheel wells out of curiousity. Would be a little sneaky to provide a quieter ride on a 5 (though a different year) since I didn't want a Five for any of the other options. Thanks.
     
  11. sthom

    sthom Junior Member

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    I'll ask a hybrid mechanic to see if changing springs is feasible on a Prius. You would think the designers would try to compensate for a rough ride if they could, since it's not an infrequent complaint, so maybe it doesn't work for the design of the car, but what do I know.
    Thanks.
     
  12. bisco

    bisco cookie crumbler

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    agreed. so much has to do with weight reduction and streamlining.
     
  13. My590L

    My590L Junior Member

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    You'd be surprised how much of the the interior trim of the car is held together just by plastic clips! I am the same way when it comes to noises that my car makes. I always seem to find new sounds/ noises. As far as the doors, I have found the same issue. My drivers side front door sounds a lot more solid when I close the door compared to the passenger side front that sounds like a tin can when I close it.

    I'm curious what you find out on your wheel wells.
     
  14. kenniekenken

    kenniekenken Member

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    I recently did some sound deadening on all my doors (including the hatch). Didn't do the entire outer panel(s) but applied the product in patches being selective due to cost constraints. Aside from improvements in music quality in the interior, another concern for me was the "tinny" doors so on the first image I applied two layers of sound deadener around the inner door handle wells and boy, I got what I wanted! My doors now sound like a luxury car in which I'm really proud and satisfied! ;)
     

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  15. sthom

    sthom Junior Member

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    Thanks for your input, from both of you, My590L and kenniekenken. The doors are tinny, apart from the driver's side, though sometimes they seem noisier and quieter when I close them, randomly. Weird. I'll have my father, who is interested in these things, investigate the wheel wells with me soon and report back. I tend not to know what I'm looking at. :)

    kenniekenken, what product did you use for damping, how did you decide where to "selectively" apply the damping material and most importantly, how easy or hard was it to do, if you did it yourself? I don't want to damage anything by trying to do it myself or not be able to put something back together. I imagined that damping material filled the spaces, such as in doors, to absorb acoustic energy or reduce vibration, perhaps from seeing pictures on websites. However, in your photos, the material appears thinner than I imagined and looks like it maybe just reduces vibration of the material it's attached to. I'm looking at the portions in your photos that looks like tin foil covering a thin square--is that correct? BTW, not all of your pics posted were visible for me, but I saw a couple of doors, and I think the hatch.

    Even though the plastic rattling is noisy, and may be contributing to loud thwacks on bumps, it is short-lived. I have to believe that the metallic parts of the car, such as the doors, are what are contributing the other noise source--the bothersome acoustics or reverb and funny air pressure I feel at times. I would like to listen to music at as low a volume as possible to preserve hearing and of course improve the quality of the sound. *Please offer more input into your materials and placement selection, kenniekenken. It sounds like something worth trying. (Tracking down sources of rattling plastic on the other hand, seems impossible and endless right now).
    Sorry I don't check in super-frequently, it's not a habit, so please bear with me.
     
  16. kenniekenken

    kenniekenken Member

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    Thank you for your interest sthom. Just a little background... I'm no pro myself and was a bit hesitant at first but then since I only had limited financial resources but was eager to learn due to my curiosity, I jumped ahead and became a DIYer. YT was my main resource backed up by reseach through sites and forums I got self taught. Enough for the segway...
    Doing the doors wasn't dificult at all. I would say about 95+ of car doors are just a couple of screws and a few clips to take out. Now for the product(s) I used yes they are fairly thin in person but seem thicker in ads and videos. I combined mainly B-quiet Ultimate and Extreme and like a Peel and Seal waterproof membrane I got from Rona. The last product being the thinnest so I doubled that on some areas particularly away from the speaker and the former down and close to the speaker. By selectively(patches) I mean mainly due to finances so what I did was by feel, I tested the "bare" door by turning up some bassy music to determine the most vibrating areas. You can never "kill" the sound but only supress it to a certain level so patches was the way to go for me.
    I really hated the door sound so I thickened my patching on the handle wells, now my doors and hatch opens and closes like a luxury car, no more tinny doors! I've also done other area like the spare wheel, hatch, rear seat, rear quarter panels, and hood. Next step is I will be applying undercoating to wheel wells, undercarriage, and other "exposed" metal parts as this also helps to deaden noise.
    For noise as it now it stands, it's gone down an average 5-6db so a definite noise reduction already. I've also learned that if there's a 10db reduction it's like noise is cut in half so for me I have another 5db to work on! This will be concentrated on the exterior and firewall areas
    For sound quality I did upgrade my rear speakers first since I have my music more inclined to the rear but will eventually upgrade the fronts. That way you can turn down the volume but still enjoy your music.
    Hope I answered some, if not all your questions and would love to discuss more.
    The forum is very prompt in giving insights, and advise when somebody needs help so I connect with people like phoenixgreg particularly for noise reduction cos he's done a rather extensive project a couple years ago.
    I'm really not into being too technical on the stuff I do and always ask first and, stay within my means until I'm satisfied cos at the end of the day you're the one who'd "know" how much of what you'll still need.
     
  17. sthom

    sthom Junior Member

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    Kenniekenken,

    I looked at the website for B Quiet and contacted them for some advice. Thanks. What sort of sound level meter do you use? Where did you measure sound--in the front seat where you would be? Or where you thought the noise was coming from just to diagnose the worst noise sources, or both? A 5-6 dB reduction is quite a lot. Sounds promising!
     
  18. kenniekenken

    kenniekenken Member

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    Hi. I'm looking at getting more Ultimates from them soon. For the sound meter I just downloaded an App called Decibel Meter Pro and measured smack middle of the car by the armrest and on my lap, the former averaged 56-58 and 50-53 for the latter. I had a peak of 86. Note that this was just a couple of runs of 5K and I'm planning on doing a few more, I guess more extensive ones soon and the roads where I drive are fairly okay so results may vary.
    Most of the noise is really coming from the engine bay and floor/firewall area so I'm going to attack those in a couple of days. Will keep you posted...
     
  19. kenniekenken

    kenniekenken Member

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    Here're a couple areas I'm going to apply product(s) to. The first pic will get BQuiets and the wheel well will get a thick 1/4" coat of undercoating all around. I'm focussing more on the front cos when driving you can get a good sense of where the noise is coming from.
     

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  20. phoenixgreg

    phoenixgreg Senior member

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    I did a similar project a few years ago:
    Dynamat wheel wells 003.JPG Dynamat wheel wells 002.JPG Dynamat wheel wells 001.JPG