Reducing cabin noise in C28?

[Headlee]

Has anyone been successful at reducing the cabin noise in the C28 by adding noise reduction material in the engine compartment? I've seen a photo or two of what looks like factory material added forward of the engine directly below the bulkhead and cabin door. This is the area that can be accessed through the hatch just forward of the door inside the cabin. I added a temporary wall I made out of stiff cardboard with folded bath towels sandwiched between and liberal amounts of duct tape. This filled about 95% of the gap, but it did not reduce the noise at all. Using a decibel meter app on my phone and located at the helm I recorded an average of 72 decibels at 700 RPM at idle and 80 decibels when revved to 1200 RPM. This was both before and after I installed temporary wall. So, there was no noise reduction at all! Any suggestions for reducing the noise would be appreciated. Thanks.

Paul

 

[Gypsy]

I have a C28 and agree that the noise level is objectionable. The only solution I have found is to close the door and turn up the radio.

 

[Severum88]

I purchased some dense foam for soundproofing and redid all of the hatches. Made a mild difference, noticeable, but not sure if I would bother unless the foam needs replacing. It was a chore to clean the old stuff and do it right. Not difficult. Just tedious and time consuming, like everything else.

 

[cliffm]

There's aftermarket automotive sound deadening material with trade names like "dynomat".

aftermarket car stereo places also have sound deadening type materials, typically is foam with foil backing that has adhesive edges, so its more or less "peel & stick". I think this is available at places like LOWES or Home Depot as "insulation" for outside of duct work. they also sell Aluminum tape for sealing up ductwork.

Close cell foam would be your preference so it won't hold water.

 

[Headlee]

Thanks for the input. I'll take another run at this somehow and let you know the results.