Sound Proofing

Robert, Super sound proofing also come with adding lbs to the Coupe. I used 1/2 " on walls and 3/4 on the fire wall. It is still in project stage. So i really cannot say how well it works. They also sell a heat blocking for the fire wall.

Most of the problem comes from the windows be thin. The exhaust rolling back under foot. .

Warren,

I took my contaminated firewall sound panels out very early so I may not have reliable recollection of the difference.

You said you purchased these before... Did you find that they help with noise when applied to the firewall?

I have a standard Airtex vinyl interior. I could apply 1 or maybe 1.5 inch material under the side panels since the frames create a gap between the Airtex panels and the aircraft skin.

I'd love to hear from someone who has tried this!

Robert Down in San Marcos Ca. is a sound proofing Company Aircraft Spruce sells it I buy from that company. they are on the net. Self sticking or without adhesive.1/4 inch to 2 inch sizes

My coupe had 1-inch foam on the cabin side of the firewall, but it was contaminated due to a brake fluid leak. After fixing the brakes I removed the foam and I can't say that I noticed a huge difference.

This is mostly speculation, but one thing I do is sound control in live music performance space. To me it seems that most of the noise I experience in the coupe is propeller pressure pulses beating against the side windows. They're thin and flexible, and their shape is a sound-focusing dome around your head.

I get less low-frequency noise with the windows down, and those lower frequencies are the ones that ANR has the most trouble dealing with. I get better results with a Quiet Technologies earplug-style headset. Additionally, it weighs <2 ounces and has no headband so it's a great thing for taller pilots in short cockpits.

I haven't flown with my new baggage compartment but it may increase my noise level since it involved removing a bunch of leather and canvas and replacing it with sheet metal and flat wood. if this turns out to be the case, I will try making a "pillow" out of fabric covered rockwool insulation panels to fit the rear of the baggage compartment. Rockwool fibers are great at absorbing sound waves (even better than fiberglass) they're cheap, and fireproof. Finding the right position and getting as much thickness for the pillow will involve some futzing around, but should be easy. The thicker the depth of rockwool (or any sound absorber) the lower the frequencies at which it becomes effective. to trap the frequencies I get in the coupe, 3-5 inches should do it.

My coupe has had the 1/4" bubble windshield since I purchased it. That's known to reduce sound which makes sense acoustically due to the material and the shapes but I haven't experienced the before and after. 

Most of the ideas I'd deploy if this were happening in a sound room would either restrict visibility, or take up too much space. So it's all a game of stacking up non-optimal solutions until you get an acceptable result. 

Has anyone tried to quiet the cabin in a coupe? I love the plane but it is insanely loud, even with BOSE A20 ANR. My straight pipes definitely do not help.  I am mainly thinking of adding 2" foam on the firewall, below the floor where the exhaust is, and adding foam any where else it will fit. Also thinking of a 1/4" windshield. Has anyone tackled this already? If so, what were the results?