Convertible sound deadening
Thread Starter
Melting Slicks
Joined: Jul 2002
Posts: 2,223
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From: Tallahassee fl
Convertible sound deadening
Does anyone have any experience on sound deadening for a C5 Convertible that actually does something and isn't stupid expensive? I have the loudest exhaust on the planet and it resonates so bad at cruise speed with the top up I can't hear the radio. I'd like to deaden the sound but don't want to throw money away. I have seen the thing that attaches to the top cover and blocks off the back, and another item that cuts the trunk into 2 parts. I tried rolling out some basic insulation as a test and it did nothing.
I'm about to pull the seats to install new seat covers so I will have access to more of the interior than usual.
I'm about to pull the seats to install new seat covers so I will have access to more of the interior than usual.
Team Owner
Joined: Mar 2001
Posts: 21,325
Likes: 3,841
From: small town in S.E Pa. PA
St. Jude Donor '03-'04
Does anyone have any experience on sound deadening for a C5 Convertible that actually does something and isn't stupid expensive? I have the loudest exhaust on the planet and it resonates so bad at cruise speed with the top up I can't hear the radio. I'd like to deaden the sound but don't want to throw money away. I have seen the thing that attaches to the top cover and blocks off the back, and another item that cuts the trunk into 2 parts. I tried rolling out some basic insulation as a test and it did nothing.
I'm about to pull the seats to install new seat covers so I will have access to more of the interior than usual.
I'm about to pull the seats to install new seat covers so I will have access to more of the interior than usual.
Bill aka ET.
Melting Slicks
Joined: Nov 2014
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From: Havre de Grace Maryland
I had factory side pipes on my '72 T-Top. I sold the car and vowed never to have another Corvette again with loud exhaust. On my C5 Vert, I have quiet Magnaflow exhaust (on car at purchase), replaced the run flat tires, put the divider in the trunk, and installed the behind seats panels you referenced to. Now I cruise with the top down radio playing and all is good and pleasurable.
Zen Vet Master Level VII
Joined: Mar 2016
Posts: 5,218
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From: Southlake, TX
There is a point to this. One of the biggest drone effect that our cars have is due to the positioning of the tail pipe tip in realation to the rear valance. The closer the tip, the sound gets "sucked" back under the car. Check for lenght as after markets vary.
It is tough to "have the loudest exhaust on the planet" that is also drone free. Lound exhausts typical compromise the "wave cancelation" portion of exhaust management trading loud for drone and vibration. I'm afraid that all the sound deadening material on your floor wont make a difference with a fabric top.
My suggestion is to get rid of the "loundest exhaust on the planet" and search for a set of Z06 titaium exhaust and skip the deading material. You have a convertible so you are fighting an uphill battle with sound. Get the TI as they sound great and are drone free.
It is tough to "have the loudest exhaust on the planet" that is also drone free. Lound exhausts typical compromise the "wave cancelation" portion of exhaust management trading loud for drone and vibration. I'm afraid that all the sound deadening material on your floor wont make a difference with a fabric top.
My suggestion is to get rid of the "loundest exhaust on the planet" and search for a set of Z06 titaium exhaust and skip the deading material. You have a convertible so you are fighting an uphill battle with sound. Get the TI as they sound great and are drone free.
Advanced
Joined: Oct 2018
Posts: 75
Likes: 4
From: SE of Indianapolis
I have the same issue. I have Billy Boat Bullets on my 2000 C5 vert and they are LOUD. I have sound deadening material on order and will install it in the spring. If this doesn't help I'll buy a eBay axle back system and call it a day. From the videos I have seen they sound fine and are less than $400. I'll sell my Billy Boats and should come out ahead.
Thread Starter
Melting Slicks
Joined: Jul 2002
Posts: 2,223
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From: Tallahassee fl
The car is actually fine with the top down, it's up that it is horrible. It's like the sound multiplies somehow. So when I say it's the loudest exhaust on the planet it's loud on the inside, on the highway, at cruise speed with the top up.
Advanced
Joined: Oct 2018
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From: SE of Indianapolis
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Burning Brakes
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Rookie here, I have hard time understanding what you guys call “drone”. Where could I find an explanation?
thanks in advance.
TCFS
thanks in advance.
TCFS
Last edited by TCFS; Dec 4, 2018 at 01:59 AM.
Drifting
Joined: Mar 2013
Posts: 1,496
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From: Little Rock Arkansas
It's similar to that basically, except not as loud. The constant frequency - or "drone" - is what drives people crazy because you're basically hearing the same frequency sound as you go down the road. Most aftermarket exhausts amplify this occurrence because they're ultimately in place to make a lot of noise for the "MOAR 'MURICA!!" factor.
Alternatives to dealing with drone or similar exhaust frequency issues is cut-outs; something GM in recent years has put on some model Corvettes from the factory. The idea is you can activate the "VROOOM" when you need it and not deal with drone on the highway when you don't need it.
Burning Brakes
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Ya, flew more than I would like to admit, actually bought sound cancelling headphones 
isn’t there a drone noise for any exhaust, whichever car and engine, then?
and in a convertible it is even more audible?
isn’t there a drone noise for any exhaust, whichever car and engine, then?
and in a convertible it is even more audible?
Drifting
Joined: Mar 2013
Posts: 1,496
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From: Little Rock Arkansas
What the OP of this post is likely experiencing is issues with sound dispersion. Sound travels in a frequency, or path, from where it is sourced; it doesn't equally expand in all 360 direction. Out of the exhaust, sound is escaping from the tail pipe out of the rear of the car. With the top or window(s) down you're hearing this sound dispersion on top of the other noises you're hearing (road, chassis movement, etc) which is not perceiving the "drone" as anticipated. With the OP's convertible top up and windows up, the sound dispersion from the exhaust is not being heard directly but rather it is coming in through it's frequency - through the chassis itself - and so their senses are picking up other sounds more strongly; aforementioned road and chassis noise and, yes, drone they likely would not normally pick up when sensing exhaust dispersion directly.
There is no "end all" solution because individuals experience sound in various ways. There are some solutions that can lower drone by their design - the Corsa Extreme setup ET mentioned is one that many C5 owners agree has a lesser drone factor - but acute individuals who sense things differently may still perceive drone in situations others would not. The "best" solution is to not modify what is currently working. Or run cut-outs.
There is no "end all" solution because individuals experience sound in various ways. There are some solutions that can lower drone by their design - the Corsa Extreme setup ET mentioned is one that many C5 owners agree has a lesser drone factor - but acute individuals who sense things differently may still perceive drone in situations others would not. The "best" solution is to not modify what is currently working. Or run cut-outs.
Burning Brakes
Joined: Jun 2017
Posts: 1,045
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From: Wichita Falls Texas
Back when I was young and a lot smarter I always wanted a loud exhaust. Now that I am old and dumb I don't.
My 03 vert has the stock exhaust system and it was really quite. Too quite, so I looked at a system for it but when i saw how much they went for I backed off.
I read this forum and learned about the exhaust bypass and had it done. Cost me $60 and it's perfect for me and my wife.
We love it and no drone either. It's got a nice sound. Some of the forum members say they don't care for it but that's their opinion and I respect that but I get a lot of people telling me it sounds good!
My vert sounds the same with the top up or down!
My 03 vert has the stock exhaust system and it was really quite. Too quite, so I looked at a system for it but when i saw how much they went for I backed off.
I read this forum and learned about the exhaust bypass and had it done. Cost me $60 and it's perfect for me and my wife.
We love it and no drone either. It's got a nice sound. Some of the forum members say they don't care for it but that's their opinion and I respect that but I get a lot of people telling me it sounds good!
My vert sounds the same with the top up or down!
Burning Brakes
Joined: Jul 2007
Posts: 1,168
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From: Springfield MA
St. Jude Donor '10-'11-'12, '19, '21
Noise
Top down ( which is all summer) no problem with road noise. Top up, different story. I use one of those oversized body pillows. It's as wide of the car and about 2 feet tall. I stuff it between the trunk and the back of the seats and you would not believe how it deadens the sound. Just sayin!!
Dave
Dave
Drifting
Joined: Oct 2004
Posts: 1,756
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Back when I was young and a lot smarter I always wanted a loud exhaust. Now that I am old and dumb I don't.
My 03 vert has the stock exhaust system and it was really quite. Too quite, so I looked at a system for it but when i saw how much they went for I backed off.
I read this forum and learned about the exhaust bypass and had it done. Cost me $60 and it's perfect for me and my wife.
We love it and no drone either. It's got a nice sound. Some of the forum members say they don't care for it but that's their opinion and I respect that but I get a lot of people telling me it sounds good!
My vert sounds the same with the top up or down!
My 03 vert has the stock exhaust system and it was really quite. Too quite, so I looked at a system for it but when i saw how much they went for I backed off.
I read this forum and learned about the exhaust bypass and had it done. Cost me $60 and it's perfect for me and my wife.
We love it and no drone either. It's got a nice sound. Some of the forum members say they don't care for it but that's their opinion and I respect that but I get a lot of people telling me it sounds good!
My vert sounds the same with the top up or down!
Burning Brakes
Joined: Oct 2018
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From: Göteborg, Sweden, Europe
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Did anyone of you put some sound absorbant on the inside of the trunk lid? If so does it help in any way?
thx,
TCFS
thx,
TCFS
Drifting
Joined: Jul 2011
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From: Boise, ID
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I agree with ET, trying to mitigate exhaust with sound deadening material is not going to yield good results. If the exhaust is too loud, recommend putting on a different exhaust and possibly installing electric cutouts so you have the option to open it up if you want but can quiet it down with the flip of a switch. Best of both worlds.
Drifting
Joined: Jul 2015
Posts: 1,844
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From: San Jose, CA
Change what? The LS likes to drone at around 1500rpm. If you have a loud, drone-prone exhaust (read: an exhaust where the manufacturer didn't bother to engineer it to minimize 1500rpm drone), you're gonna have drone. The stock exhaust, being both fairly quiet and fairly well engineered to avoid that drone, doesn't really drone; a large handful of aftermarket exhausts (the majority, I would say) do, to a larger or smaller extent.
You can sound deaden all you want, but that resonance bloody well penetrates. It's not just simple sound, it goes through the damn car and into the passenger area and bounces around ... around the passenger compartment, around your skull. It'd take a hell of a lot of sound deadening to stop that.
My solution to the drone problem was to roll my window(s) down or, better yet, to take the top off, if I plan to be cruising down the highway at ~69mph in 6th gear, which is the drone hotspot.
I can always avoid the issue by driving faster in sixth, or driving in fifth. Just avoiding the 1500rpm cruise really works well. Free, too, except for a bit more gas consumption.
You can sound deaden all you want, but that resonance bloody well penetrates. It's not just simple sound, it goes through the damn car and into the passenger area and bounces around ... around the passenger compartment, around your skull. It'd take a hell of a lot of sound deadening to stop that.
My solution to the drone problem was to roll my window(s) down or, better yet, to take the top off, if I plan to be cruising down the highway at ~69mph in 6th gear, which is the drone hotspot.
I can always avoid the issue by driving faster in sixth, or driving in fifth. Just avoiding the 1500rpm cruise really works well. Free, too, except for a bit more gas consumption.