These are far from the frequencies typically classified as "road noise". With C-weighting, this showed as 102-103dB on the rough highway, at 61Hz. Initial readings showed 90-91dB at 60mph on rough highway at 400Hz, 78dB at 60mph on smooth, fresh pavement. I wouldn't remove the IMA box, but I would add material under and to the sides of it, without covering any ventillation holes. Pieces would be cut to cover every surface in the car, up to the top of the wheel wells, up halfway the firewall, etc. My plan was to adhere the mlv to the ccf with DAP Landau Top and Trim adhesive. I expected to use 50 square feet of material in the Insight, with a huge drop in road noise. To start, I picked up a cheap calibrated mic (Dayton iMM-6) to use for comparison of the before and after. This would be my first time using MLV in a custom install. I've had good luck with those other products in layers, with thin closed cell foam as the final "barrier", some 10 years ago. I skipped products like Dynamat, Damplifier, RAAMmat, etc since the goal is mainly to block road noise. I'd do the doors, wheel wells/arches and boot first to see how you get on.In an effort to quiet down the noisy Insight, I picked up 100 square feet of 1/4" closed cell foam (ccf) and 100 square feet of 1lb mass loaded vinyl (mlv). Then on the back of the door cards I've added this I bought this stuff but there's cheaper around You need 100% coverage here to be effective or it's just wasting money. Once that's done I'd add MLV (mass loaded vinyl) which is heavy sheets of vinyl and really cuts down on noise. This stuffs just as good as what cad sell imo, and easier to work with. To go a bit further (may aswel while your at it) add some CCF (closed cell foam) over the inner skin. Once the door skins deadened you can either leave it like this (but I'd seal up any large panel gaps, just make sure the card will go back on) this will make a noticeable difference but won't stop any outside road noise or passing cars/trucks. Some just say to deaden 25% of the door! other 100%.I'm in the 100% club! I've gone for silent coat for the last 2 cars and can't fault it.īasically what you need to do is, whip the door cards off, clean any dust or old bits of deadening off the metal then deaden both outer & inner door skins. Takes hours to do properl (days!!)ĭynamat's great but very expensive. Tbh it sounds like the shop didn't want the job on as its a load of work to instal and very labour intensive. Breakers have no use for it and so sell it for a pittance, so I bought some for nothing and used it all over. I don't know the proper name, but my car has a wool / fluff stuffing that is used in a few places.I've also used some "fluff"* to fill crevices around the rear seat / boot aperture. You can get proper car stuff for £££, but I've used Cloud 9's Nimbus carpet underlay with good effects (on the floor, stuck to the back of various panels, along the boot floor / wheel well, even inside my PC!). I've used Dynamat on some panels, but what I think works better (from an NHV point of view) is to use layers of foam. Dynamat is designed to stop the panels vibrating - but not to actually block out any real noise. Dynamat is good at what it's designed for - but if you want to reduce road noise it's not the best product.ĭynamat is designed to "stiffen" panels - if you have a beefy sound system, large panels (door skins, roof, bootlid) can vibrate and act like an out-of-phase speaker and kill the harmonics.
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