Sound barrier

We are looking to add a sound barrier in order to reduce noise in the main cabin while running. We have investigated a product called Soundown, has anyone had experience with this product? Our current decibel level is 82 while running at 1700 rpm and would like to drop it by 20 db’s. Thanks in advance for all your opinions.

I have used Soundown with good results. One of our TF members works there and was super helpful. Keysdisease is his handle, or TF name, or wherever it’s called. Lol.

Soundown is the "go to" company for all things in the noise reduction department.

Call Sundown’s Fort Lauderdale office and ask for Steve. When we did our engine room outfit, he stopped by to offer some sugestions. We were in Jacksonville.

Ph 954-761-9188

Also check your engine mounts to make sure you're not turning your boat hull into a sounding board with the engine vibrations. If you're picking up a lot of low frequency noises, those usually come through the engine mounts or exhaust systems.

Also see if running different combinations of engines / gensets changes the amount of cabin noise. If you hear more noise with the genset, that should be your first target.

Many years ago I used their decoupled foam on the underside of my salon sole.

Especially on the engine hatches. The foam made a big difference.
Don't know about about 20dB but a big difference.

It is now time to redo it as the foam has reached its end of life and is breaking down.

One thing to check though is the fit of any hatches and any openings to the E.R.
Even small openings and gaps will allow an amazing amount of sound/noise through. Either close them completely or figure out a way to absorb the sound they transmit without closing the venting.

I have used it in several previous boat with good success.

stubones99 said:

Also check your engine mounts to make sure you're not turning your boat hull into a sounding board with the engine vibrations. If you're picking up a lot of low frequency noises, those usually come through the engine mounts or exhaust systems.

Also see if running different combinations of engines / gensets changes the amount of cabin noise. If you hear more noise with the genset, that should be your first target.

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This is very true. My generator sound box was mounted directly to a flat wooden area on my boat, and that big wooden area acted like a speaker transmitting the vibration all over the boat. I used some of Soundown’s isolating mounts underneath the gen box and it made a huge difference. The generator itself inside he sound box has typical rubber engine mounts but they transmit much of the vibration unlike these well engineered Soundown mounts.

My diesel is directly under the main cabin. The top of the engine is about 5" below the top of the cabin sole. I installed 2" of soundown all around the engine (sides, back, front and top. The result is that you can carry on a normal conversation at wide open throttle even when standing directly above the engine.

I installed isolation mounts and additional decoupling foam from Soundown when I installed my new engine. Very happy with the reduced noise levels.

Ted

I sold Soundown in my store for many years. Good product and nice people.
If you mount it overhead, don’t just rely on the glue to hold it up. Buy the spikes they sell to mount it.

I used 5200 and really short screws to mount the spikes. A few spikes on vertical surfaces isn’t a bad idea either. See step 3 in the installation instructions.
http://www.soundown.com/Section 3 PDFs/Installation Instructions.pdf

Yes, I should have added about the mounting.
I bought many of the spikes but eventually went to SS screws and LARGE FENDER washers.

No glue.

Gbinterim said:

Our current decibel level is 82 while running at 1700 rpm and would like to drop it by 20 db’s. Thanks in advance for all your opinions.

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82db at 1700rpm is very high. You probably have an open air path from engine room to the cabin somewhere. Find and fix that first.

Soundown is good (though expensive product). As I mentioned on another thread few months ago you can save $$ by buying mass loaded vinyl + neoprene foam + fire blankets in bulk and gluing them together.

82-20=62db is NOT achievable no matter what product you will use. At 8kt the sound of the rushing water from outside will be at least 66-68db. Good sound insulation (which you see on some expensive 50-60ft trawlers) gives you ~68-70db at hull speeds. With DIY project your realistic target is probably around 70db (depending on engine room space/layout), which is still 4 times quieter than 82db

Alex

C lectric said:

Yes, I should have added about the mounting.
I bought many of the spikes but eventually went to SS screws and LARGE FENDER washers.

No glue.

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I also used the as screws and large fender washers on the overhead. Engine hatch. I couldn’t figure out how to use contact cement on both surfaces and then try to orient the material above the spikes so I put it down with the cement and the screwed through with the fender washers until it was just snug but didn’t compress the thickness. Worked great.

I cut the material and “dry fit “ it. Then taped one side with three pieces of tape so I could lay it back. Then applied the contact cement to both surfaces (hatch and soundproofing). When dry then the tape allowed me to fold the material back over like closing a book and stick it in the original layout. Then I screwed in the fender washers.

Installed Sounddown (about 1/8 inch thickness) under new carpet and conditions were noticeably improved. Db's dropped by 15 at most and result is about 75 Db average. Actual results depend on location measured. Big mistake was leaving a 1 inch+ gap around the perimeter at suggestion of carpet people; simply for "looks". Going to the edge would have been even more successful. Installed it all with a cutout - fold back section over the the main hatch in the sole. Leaks a little noise, but is easier to negotiate the opening of same.

Here's a link to my recent upgrade with Soundown Carpet Underlayment. The amount of attenuation varies with frequency but my improvements ranged from 15-20 dB at frequencies above 500 hz.

http://www.trawlerforum.com/forums/s32/soundown-carpet-underlayment-installation-38420.html

I will add that Steve/Keysdisease at Soundown was a pleasure to deal with.

How do you guys mount it with screws and washers?

When I tried that I used an ice pick to punch through he foam and barrier. Then when I ran the screw in it tore a big chunk of foam out. That’s why I switched to the spikes.

I think I was using #10 screws and fender washers.

Check this out. Used their product to replace the insulation on a generator enclosure. Worked great. Acoustiblok.com.

HopCar said:

How do you guys mount it with screws and washers?

When I tried that I used an ice pick to punch through he foam and barrier. Then when I ran the screw in it tore a big chunk of foam out. That’s why I switched to the spikes.

I think I was using #10 screws and fender washers.

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Hi Hop,

Run the driver in reverse to punch through the foam. That will avoid the tear out. Then forward to drive the screws. Worked for me.

Rob

Thanks Rob! Good trick to know.

Datenight said:

Hi Hop,

Run the driver in reverse to punch through the foam. That will avoid the tear out. Then forward to drive the screws. Worked for me.

Rob

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Yup, just like using a hole saw in vinyl upholstery, run it in reverse.

What works well and helps keep the washer on the screw (especially when working an overhead) is to use an icepick or awl to make your hole in the insulation. Wrap masking tape around the drill bit to make your pilot hole if necessary. Wrap the screw with tape and drive the screw until the face of the insulation just dimples.

The tape will reduce the chances of the tool or screw grabbing the foam and balling up

HopCar said:

How do you guys mount it with screws and washers?

When I tried that I used an ice pick to punch through he foam and barrier. Then when I ran the screw in it tore a big chunk of foam out. That’s why I switched to the spikes.

I think I was using #10 screws and fender washers.

Click to expand...

Datenight said:

Hi Hop,

Run the driver in reverse to punch through the foam. That will avoid the tear out. Then forward to drive the screws. Worked for me.

Rob

Click to expand...

Acoustiblok is mass loaded vinyl (MLV) and is available without the trade name (basically generic) at plenty of outlets. I've even seen it at Lowes.

1lb (1/8") MLV has an STC of 28 all by itself, its the barrier in all the insulation products discussed this thread, and its the all purpose noise barrier / lead replacement used in the noise control industry.

hmason said:

Check this out. Used their product to replace the insulation on a generator enclosure. Worked great. Acoustiblok.com.

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Hi Keys, did I meet you when I went up to Lauderdale to pick up Soundown?

FWIW, 6mm acoustical cork is super easy to apply and designed to significantly reduce the noise between floors in high rise buildings. I lined Delfin's hull with it as a base layer before 2" Coast Guard fiberglass batts and even with the dry stack that exits through the "stack house" about 12" behind the pilot house, the db level in the PH with a CAT 3306 rumbling below is around 68 db. Certainly use Sounddown's acoustical foam vinyl sandwich, but line the area with cork first. You'll be very glad you did.

http://www.jelinek.com/product-information-cork-underlayment/

I'm going to revive this older thread on Soundown, rather than keep posting in the asbestos thread.

Has anyone used any of the hardboard Soundown products? I want to replace a "wall" on GRP "studs" in my KK. I need to be able to affix things to it. I'd prefer something that wasn't wood.

When we redid our engine room we used Soundown perferated aluminum. On the outboard walls we didn’t need sound insulation. We used marine ply and then went over that with their perforated aluminum. We’ve hung the water maker membrane, a back up charger and plumbing. That was three plus years ago and it’s worked well.

https://soundown.com/wp-content/uploads/2018/02/MAR-QuieTech-2010.1.A.pdf

Beautiful. That's exactly what I was looking for...

I worked with Steve from Sundown’s Fort Lauderdale office. He had good sugestions and saved me a lot of money. They shipped stuff the day I ordered. Ph 954-761-9188

We used the same material for the ceilings to replace the peg board. If you need more pictures let me know.