Soundproofed the car today
Joined: Sep 2002
Posts: 4,594
Likes: 71
From: Judo Town, USA
Hey, everyone- please listen up.
I feel that a lot of people may not understand just how important this whole issue is.
Let me start off by saying that my specialty is not ENT, I'm enrolled in Anesthesia School, but I have had a lot of education related to ENT, and especially Audiometry, and hearing loss. I am a Licenced Occupational Audiometrist, and also have Certification as a Occupational Hearing Conservationist. I needed to get it when I worked in Occupational Health.
The pipes that I'm running on my S are 2.5 inches, with (2) 12 inch Ti Mufflers, and I have left the OEM resonator and dildo attached, to reduce resonance. I have no problem from 4700 RPMs to redline, but below that, the pipes are way too loud.
I know that a lot of you are running aftermarket pipes without the OEM pieces. I can't imagine that anyone's pipes are louder than mine, but the guys at Spugen assure me that many pipes are louder.
I haven't had the opportunity to measure the sound levels on my car with a dB meter, but I don't need one to know that my car is definitely loud enough to cause permanent hearing loss. I can not tell you how much loss, or how long it would take to do some serious damage, but I can tell you that I won't be driving around like this for long!
My mufflers come with silencers, so I can put them in, but they will reduce my HP, and look crappy. I also had them in for a minute, when we installed the pipes, and one of them was buzzing, so I prefer not to use them. However, if I can't tone it down enough, by using these other techniques, I will probably have some silencers custom made, that won't cut down the pipe diameter so much.
I am very concerned about other owners who may not realize the damage that they are doing to their hearing, and may not realize it, until it is too late. I know that no one wants to end up deaf, or with severe hearing loss, or permanent tinnitis (ringing in the ears). All of these scenarios are possible.
Please be careful, and consider what is being offered here.
-Pete
I feel that a lot of people may not understand just how important this whole issue is.
Let me start off by saying that my specialty is not ENT, I'm enrolled in Anesthesia School, but I have had a lot of education related to ENT, and especially Audiometry, and hearing loss. I am a Licenced Occupational Audiometrist, and also have Certification as a Occupational Hearing Conservationist. I needed to get it when I worked in Occupational Health.
The pipes that I'm running on my S are 2.5 inches, with (2) 12 inch Ti Mufflers, and I have left the OEM resonator and dildo attached, to reduce resonance. I have no problem from 4700 RPMs to redline, but below that, the pipes are way too loud.
I know that a lot of you are running aftermarket pipes without the OEM pieces. I can't imagine that anyone's pipes are louder than mine, but the guys at Spugen assure me that many pipes are louder.
I haven't had the opportunity to measure the sound levels on my car with a dB meter, but I don't need one to know that my car is definitely loud enough to cause permanent hearing loss. I can not tell you how much loss, or how long it would take to do some serious damage, but I can tell you that I won't be driving around like this for long!
My mufflers come with silencers, so I can put them in, but they will reduce my HP, and look crappy. I also had them in for a minute, when we installed the pipes, and one of them was buzzing, so I prefer not to use them. However, if I can't tone it down enough, by using these other techniques, I will probably have some silencers custom made, that won't cut down the pipe diameter so much.
I am very concerned about other owners who may not realize the damage that they are doing to their hearing, and may not realize it, until it is too late. I know that no one wants to end up deaf, or with severe hearing loss, or permanent tinnitis (ringing in the ears). All of these scenarios are possible.
Please be careful, and consider what is being offered here.
-Pete
Thread Starter
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Joined: Jul 2002
Posts: 488
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From: Estes Park
Brian, I'll answer your question about dynamat. It is an asphaltic based damper that works on the theory of mass. Two problems are that it takes a lot of mass to damp with asphalt, and it is soft, which allows it to flex, and that allows tranmission of sound. If you read stories about dynamat, lots of people have plastered their car with it and complained that the noise level hasn't changed. That is not surprising, because dampeners are not designed to stop noise, they are designed to stop flex of metal, which causes noise to be transmitted elsewhere. As the temperature varies, all dampeners change the frequencies at which they are effective, and asphalt is the worst of these. Then, of course, there is the issue of weight. Our dampener, developed for use in aircraft, has to be sized for the thickness of the metal substrate, the temperature range to be encountered, and for the lightest possible weight. This is a specifically engineered product for the application. I can get higher quality plastic/asphalt/aluminum dampers than dynamat for 1/3 the price, but they simply do not compare. A simple knuckle rap on a damped fender will vividly demonstrate this to you. also, cars are operated at huge temperature extremes, and the engineered material works in this range with minimal degradation.
Many people wrongly assume that the whole area needs to be covered. Covering about 60% of the area of a large panel will stop 90 % of the vibration. I will give specific instructions for the car with the kit. After the flex and vibration are dealt with, we have to stop the airborne noise. To do this best requires that we isolate the next radiating surface in line, be it carpet, panels, or trunk liners. Ever noticed that if you fold down the rear seats in a sedan that lets you, the noise is a lot louder? This is the same problem we have, only the fold down seats are replaced by the flow through vents.To have effective subwoofer projection and protection from the ear splitting din of the pipes the trunk area must be quieted. Also the other major areas of concern are the firewall, transmision tunnel, floor pan, and door panels. The factory has made some attempts in these areas, and some we will change totally, some we will leave alone, and others we will augment. If it works from the factory, we'll use it. But, by removing some of the heavy, but ineffective, factory material, a net weight gain of 11 to 12 pounds is possible, not bad at all considering the considerable improvement. When you close the doors, you'll get a solid thunk, the exhaust will sound louder because the road and gear noise is reduced, you can turn down the stereo and save your hearing (if you have any), a lot of small rattles and buzzes go away, and the noise of gravel hitting your fenders won't sound like shot peening. The only flaw we can't address is the lack of a headliner for the top. The hood actually has a very good blanket, so Honda must have been very aware of the noise areas there. Stay tuned, as I work on real world sound levels very soon. Oh, and besides price, Dynamat doesn't work very well.
Many people wrongly assume that the whole area needs to be covered. Covering about 60% of the area of a large panel will stop 90 % of the vibration. I will give specific instructions for the car with the kit. After the flex and vibration are dealt with, we have to stop the airborne noise. To do this best requires that we isolate the next radiating surface in line, be it carpet, panels, or trunk liners. Ever noticed that if you fold down the rear seats in a sedan that lets you, the noise is a lot louder? This is the same problem we have, only the fold down seats are replaced by the flow through vents.To have effective subwoofer projection and protection from the ear splitting din of the pipes the trunk area must be quieted. Also the other major areas of concern are the firewall, transmision tunnel, floor pan, and door panels. The factory has made some attempts in these areas, and some we will change totally, some we will leave alone, and others we will augment. If it works from the factory, we'll use it. But, by removing some of the heavy, but ineffective, factory material, a net weight gain of 11 to 12 pounds is possible, not bad at all considering the considerable improvement. When you close the doors, you'll get a solid thunk, the exhaust will sound louder because the road and gear noise is reduced, you can turn down the stereo and save your hearing (if you have any), a lot of small rattles and buzzes go away, and the noise of gravel hitting your fenders won't sound like shot peening. The only flaw we can't address is the lack of a headliner for the top. The hood actually has a very good blanket, so Honda must have been very aware of the noise areas there. Stay tuned, as I work on real world sound levels very soon. Oh, and besides price, Dynamat doesn't work very well.
Joined: Sep 2002
Posts: 4,594
Likes: 71
From: Judo Town, USA
Hi, everyone!
As I have posted in this thread, IMO, this is a very important product.
chipperman has contacted me, and asked if I would realistically evaluate his kit, whenever it is ready. I won't be getting the kit for free, but I may get a discount. I want you guys to know that my opinions on this kit will be completely unbiased. This issue of protecting our hearing is just too important to me.
I think he chose me to evaluate the kit based on my background, and also based on my attention to detail with the other mods that I have done to my car. Since he will be doing actual sound level testing, my input will be mostly subjective about the levels of sound dampening, and objective about the fit and look of the kit. I'll take lots of pics of the installation, and I will post all of the details, as usual.
Keep in mind, that this kit is not just intended to reduce the sound levels transmitted to our ears from outside the cockpit, but also to enhance the sound quality of our stereo and in-car entertainment systems.
chipperman overnighted me some samples of the materials that he is using, and some of them are really impressive. There is one that he labeled "Aircraft Dampener," and I can tell by looking at it, that it has to be expensive. It's some kind of greenish-brown flexible plastic material, and the back of it is like aluminum. Not like aluminum foil, like thin flexible sheet aluminum!
The other stuff is like closed cell foam (two types) one with a micro cell construction and a paper covered adhesive on one side. There is something else labeled "Mastic Dampener," which is like a black rubbery consistency, with an aluminum foil kind of backing, and a paper-copvered adhesive on the other side.
I'm not sure if he is using all of these materials, or if he is just experimenting with them.
This is all I have to offer you guys, at the moment, but this project is looking like a very high-end product, which is certainly appropriate for our beautiful cars.
-Pete
As I have posted in this thread, IMO, this is a very important product.
chipperman has contacted me, and asked if I would realistically evaluate his kit, whenever it is ready. I won't be getting the kit for free, but I may get a discount. I want you guys to know that my opinions on this kit will be completely unbiased. This issue of protecting our hearing is just too important to me.
I think he chose me to evaluate the kit based on my background, and also based on my attention to detail with the other mods that I have done to my car. Since he will be doing actual sound level testing, my input will be mostly subjective about the levels of sound dampening, and objective about the fit and look of the kit. I'll take lots of pics of the installation, and I will post all of the details, as usual.
Keep in mind, that this kit is not just intended to reduce the sound levels transmitted to our ears from outside the cockpit, but also to enhance the sound quality of our stereo and in-car entertainment systems.
chipperman overnighted me some samples of the materials that he is using, and some of them are really impressive. There is one that he labeled "Aircraft Dampener," and I can tell by looking at it, that it has to be expensive. It's some kind of greenish-brown flexible plastic material, and the back of it is like aluminum. Not like aluminum foil, like thin flexible sheet aluminum!
The other stuff is like closed cell foam (two types) one with a micro cell construction and a paper covered adhesive on one side. There is something else labeled "Mastic Dampener," which is like a black rubbery consistency, with an aluminum foil kind of backing, and a paper-copvered adhesive on the other side.
I'm not sure if he is using all of these materials, or if he is just experimenting with them.
This is all I have to offer you guys, at the moment, but this project is looking like a very high-end product, which is certainly appropriate for our beautiful cars.
-Pete
Registered User
Joined: Sep 2002
Posts: 2,431
Likes: 2
From: Dragon country
This is great! Thanks again chipperman - the info alone is priceless! 
Thanks to you to Kodokan for volunteering to be a test monkey.
Your experience in this area will make you a good second source "sounding board" for testing and applications.
I'm really glad to see that this project is going to get past the development stage. A kit would be fantastic!
Take your time to consider all the angles - we can wait!
I'm probably fixing to show my ignorance on this subject but I've wondered if the (incredibly thin/cheap) floor of the convertible top well isn't a culprit for noise transfer. Would it be of any benefit to line the bottom of this piece?
Thanks to you to Kodokan for volunteering to be a test monkey.
Your experience in this area will make you a good second source "sounding board" for testing and applications.
I'm really glad to see that this project is going to get past the development stage. A kit would be fantastic!
Take your time to consider all the angles - we can wait!
I'm probably fixing to show my ignorance on this subject but I've wondered if the (incredibly thin/cheap) floor of the convertible top well isn't a culprit for noise transfer. Would it be of any benefit to line the bottom of this piece?
Registered User
Joined: Sep 2002
Posts: 2,431
Likes: 2
From: Dragon country
Kodokan,
You might have misunderstood my inquiry. I was speaking of the thin plastic/cardboard (?) barrier between the trunk and the area (the "well") that the top folds into. As far as the top itself - I'm aware that there is a liner that can be purchased. It's rather expensive considering that it drops decibel levels only by a reported 3%. Maybe some of the dampening material chipperman speaks of could enhance the sound deadening qualities if placed between the liner and top. Don't know how much space would be available for that though. Maybe someone who has already purchased the top liner would be willing to experiment with this idea(?)
You might have misunderstood my inquiry. I was speaking of the thin plastic/cardboard (?) barrier between the trunk and the area (the "well") that the top folds into. As far as the top itself - I'm aware that there is a liner that can be purchased. It's rather expensive considering that it drops decibel levels only by a reported 3%. Maybe some of the dampening material chipperman speaks of could enhance the sound deadening qualities if placed between the liner and top. Don't know how much space would be available for that though. Maybe someone who has already purchased the top liner would be willing to experiment with this idea(?)
Joined: Sep 2002
Posts: 4,594
Likes: 71
From: Judo Town, USA
Ravenwerk-
I did misunderstand your post, but after re-reading it, it is perfectly clear which piece that you mean.
You can be sure that chipperman is looking at everything. He's mentioned stuff to me about the trunk, fenderwells, cockpit, engine compartment, and everything in-between. From the info that he is giving me, I can tell that he is extremely knowledgeable and detail oriented. He's also been taking sound measurements all over the car, in every configuration (top up/down, windows up/down, various RPMs, radio on/off and high/low volume), and is doing the testing while actually driving the car (on various types of surfaces).
-Pete
I did misunderstand your post, but after re-reading it, it is perfectly clear which piece that you mean.
You can be sure that chipperman is looking at everything. He's mentioned stuff to me about the trunk, fenderwells, cockpit, engine compartment, and everything in-between. From the info that he is giving me, I can tell that he is extremely knowledgeable and detail oriented. He's also been taking sound measurements all over the car, in every configuration (top up/down, windows up/down, various RPMs, radio on/off and high/low volume), and is doing the testing while actually driving the car (on various types of surfaces).
-Pete
Thread Starter
Registered User
Joined: Jul 2002
Posts: 488
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From: Estes Park
Ravenwerk, you are very right about the top well being a problem, but it is reradiating sound induced in the tool well and floor panels from the exhaust, tires, and differential. I am evaluating materials, measuring decibels, and using a frquency analyzer to obtain the lightest, most cost effective cure. At present, idle noise is down 10 db, other sounds 5 db. A level reduction of 10-12 db is the goal. The project will be finished in a couple of weeks and I'll have real data then. I was measuring exhaust levels at autocross on Sunday, and out of 200 cars under full throttle, ours in stock form were the fourth quietest. So the trick is to keep the noise out of the cab; it's not bad on the street.