SonexBuilders.net

Would like to try and quiet down inside noise. Anyone have ideas what is the best thing to put on the inside firewall.
John

I spent a lot of time trying things out and nothing was very effective. Here's a link to my report on the Sonex Australia site https://www.sonexaus.org.au/galleries/building-tips/cockpit-noise/ so that's a list of what didn't work, or at least not very well.

Since doing those flights and that report I have also tried muffling the engine a bit better. The mufflers were only little "hot dog" absorption mufflers on the tail pipes but didn't really make any measurable difference in the cabin.

Peter

Bose A20's - but on your ears - not on the firewall. :-) Said with a smile.

YMMV

I'm also using the Bose A20's, and I agree with Graeme. At my age I need all the help hearing I can get.

I have Bose A20s and agree that they work well but when I talk on the intercom to a passenger the microphone does a great job of picking up the cabin noise so that I am talking over a roar, which was the reason I was originally trying to reduce cabin noise. I have a Flightcom 403MC intercom connected to a Microair radio. If anyone has any advice on reducing that roar I would love to hear it. I have tried different mics on other headsets but no improvement.

Peter

Has anyone done a FFT of the cabin noise to see if there is anything in particular dominating the noise footprint?

peter anson wrote:I have a Flightcom 403MC intercom connected to a Microair radio.

My old MGL and my current Garmin radios - both with combined Intercoms had a setting to adjust for sensitivity of dealing with background noise. Don't know about yours - but that's the first place I'd look.

Thanks Peter, great link. At least I know what doesn't work. I have a Lightspeed ANR set of headphones which work great but was thinking the quieter the better. Without the anr it is almost unbearable. Thanks everyone! John

My old MGL and my current Garmin radios - both with combined Intercoms had a setting to adjust for sensitivity of dealing with background noise. Don't know about yours - but that's the first place I'd look.

Damn, you're right. It does too. There's a trim pot hiding under a punch out foil cover. Thanks!

Peter

I used a heat shield material on the inside of the firewall. Meant for cars, got it off Ebay. This was fitted during the build so I cant give a before and after report on the noise reduction. I also tried sticking thin foam insulation onto the panels behind the seat, no noticeable improvement there. ANR headset works the best with a mic muff. Sometimes the battery runs out while flying, get me every time, sudden jump with the noise increase until I realise what's just happened.