The Sound of Silence: Our Battle against Engine Noise | SV Ramble On

[@nigelha3699]

been doing this on our power boat.... The db doesn't change much, but the type of sound we hear certainly does. Most of these products can't block out the lower frequencies. The wood and fibreglass panel its self is a speaker. I add mass, like Megasorber D14 directly to the panel, so with the added mass, it vibrates at a lower frequency, one we cant hear [hopefully] and then you add the absorber to try and convert the sound wave to heat. You can also try a blocker like mass loaded vinyl. Thick alu plate sandwiched with a butyl works well too. You need to seal every edge. I would also expect that a lot of sound travels up the wooden frame in to the cabin, again the wood will vibrate as quite a good speaker. D14 [like Dynamat] will add mass to those reducing their vibration. In several areas I added about 4 layers of D14 and I felt this really helped reduce the vibration and lower frequency noise. Those diesels are really loud. As you fix one area, then you will hear another...

[@bajatrawler7325]

Rich, it doesn't matter if the decibel meters are not that accurate. What matters are the before and after levels using the same app. The readings are relative. It sounded quieter to me. Good video. Keep em' coming.

[@pierrevanhalteren5733]

Good sound proofing material needs to be heavy to perform well unfortunately. They come quite expensive.

[@allynonderdonk7577]

I do home theaters. You need to add latches and some durable, double line of rubber seals around the covers and any penetration. A little hole can let all the sound through. Though the engine has to breathe!!!

[@KayZee1957]

Foam is for controlling sound IN the space. It's only mass that reduces sound transmission. In the REAL stuff the foam isolates the lead layer so it "floats." The foil protects the foam from heat.

[@leps69]

You need top glue acoustic aluminium plates and in between them glue some insulations pens.When pens are cured use 30/36 insulation. After first layer of insu put 1mm rubber and than fishins with 30/66A insulation. Its best what u can do. Or you can choose 40/36 insulation in first layer if u have space but second insulation layers 30 in good. Accoustic aluminium plates will stop alot of vibrations.

[@stephenburnage7687]

I was wondering if you ever found anyway to improve on your sound insulation? I undertook a similar project to you but with only a minimal improvement. It would theoretically be possible to increase the thickness of the insulation (or use a better product) but space is limited. Also concerned about heat dissipation and flow of air for combustion. Was wondering whether insulating the bilge area (under the sump) and/or insulating the silencer (muffler) and/or closing numerous minor air gaps might improve things. Did you go back and have a second look at sound levels, after this first attemp to reduce noise & vibration?

[@svrambleon]

We did improve it, but not with insulation. We bought a new engine and it's a bit quieter. That's not why we bought it though.

[@lsmalley]

Unfortunately that light weight foam does nothing to deaden sound. If you want a huge improvement you need to have something with weight to it. Think of slamming a hollow aluminum door completely filled with cotton balls. Now think of slamming a hollow aluminum door completely filled with wet cotton balls. A couple of layers of aluminum flashing tape (with the butyl backing, NOT asphalt) should work.

[@jelleklinge9743]

Te hole plates on your old engine sound isolation are much more efficiënt at sound dampening. This works via the Helmholtz principle, so the difference (what you measured) is not that big. underneath yout helmholtz you put some deadening mat like kilamat. Then you will have a big difference. You could fill the room in your helmholtz plates, that also would be more efficient. Please go search the internet about Helmholtz, you will find out.

[@therarebreeds77therarebree7]

You really need to cover the entire inside of that thing and not just sections. When you soundproof a home, it is the same thing - you can have no leaks.

[@catalinadude6218]

That stuff looks pretty cheap, it's basically just light weight foam. I have never had any sound proofing in the Dude and just bought some from Defender. It's half inch but has a very heavy core in it. I just started to put it in. I'm hoping for a big change!

[@hanssolo4ever]

You can double it up, I have done that before and that makes a difference.

[@svrambleon]

We don't really have the space to add another layer.

[@johnchristensen4002]

Rich whare did you get your soundproofing panels? Thanks.

[@svrambleon]

I’m pretty sure I got it at McMaster Carr

[@thebostonaudiophile]

What’s your great intro music? I have that on LP but I cannot remember which record (I have thousands)? Thanks!

[@svrambleon]

It's a clip that's included in the Final Cut Pro X audio library. It's called Collins Avenue. I have no idea who the artist is though. Sorry.

[@thebostonaudiophile]

SV Ramble On Thanks for replying!

[@theislandpackrat]

Is that the kind with lead in it? I have a piece I've had for years but it's so heavy that would add a lot of weight tho!

[@svrambleon]

Nope, ours doesn't have lead in it. Being in California (the nanny state) I doubt we could even find anything like that. Seems it would be really heavy!

[@rhino_sailor7506]

It’s not that heavy guys ...

[@6226superhurricane]

definitely took some of the harsh clatter away by the sound of it.

[@svrambleon]

We thought so too! Just a little surprised the decibel meter app didn't show it.

[@karencook4588]

I like this idea. Just wondering if there is any concern about the actual engine compartment getting too hot with less air flow?

[@svrambleon]

Yep, we're wondering the same thing. Next time we motor out we're definitely going to keep an eye on the temperature. We do have a bilge blower near the engine, but it's not connected at the moment.

[@stephenburnage7687]

You also have to think about a good flow of air for combustion. Diesels typically require a minimum air::fuel ratio of 14.5.

[@sailingaphrodite4189]

Very odd that the decibel readings are the same before and after fitting the sound insulation. Pity you did not open that small lid under the steps before you did the insulating. Given that this was posted in 2019 I wonder what your thoughts are after two years, assuming you were able to use the boat during the COVID pandemic?

[@hanssolo4ever]

How long have you been rebuilding it?

[@waynemazan7485]

there must be a better system out there.... thanks

[@gking5522]

I agree with Baja. I put in the same material 5 years ago and did notice a difference. You'll probably notice more of a difference when you're underway. Hope so anyway. G SV Intuition

[@markjennings2315]

So there was no difference??

[@svrambleon]

Hey Mark, it's hard to say with a free iPhone App clocking decibels, but audibly to the human ear it definitely made a pretty significant difference. The next obvious thing to do would be to install some positive latching fasteners to secure the engine cover and alleviate additional rattling from wood-on-wood vibrations. It's a Perkins, and they're pretty noisy to begin with.

[@petemarsh8782]

Every 2 db cut is equal to 1/2 the perceived noise.

[@svrambleon]

Thanks Pete, Jeni said she noticed a difference in the volume level I need to install some hold-down latches on the engine covers and that'd probably help reduce some of the clatter as well.

[@CaptureAVtube]

So, no difference then!

[@svrambleon]

I wouldn't say no difference. The decibel apps did not register a noticeable difference, but we could hear a difference. The noise was definitely muted. Doesn't make much difference now since we're getting a new Beta Marine any day now. We'll see if it's quieter.

[@clevans24]

purchase an acoustic sound tile or barrier foam.