I bought a Wensn
30-130 Decibel sound meter off
fleabay. I use it to record
sound levels in front of my face
in flight.
I first tested my
RV-8 after installing a turn
down tip, but was also
experiencing severe exhaust
leaks from my turbo: 19.7 DBa
After fixing the leak, I
recorded 16.8 DBa
Then I squeezed the turn down
tip to a flattened rectangle
opening, and replaced the lost
area with 1/4" holes, which I bent
to face backwards with a Philips
screwdriver. a Piccolo Pipe, as
it's known. Kind of a cheese
grater for sound waves. Next
reading: 14.6 DBa
This is still to loud for my
worn out ears, so I bought an
Aeroturbine 2525 muffler, as
described on this forum. I've been
collecting 304 stainless pipe
bend, ball joints clamps and
hangers. I hope to get something
cobbled together this weekend.
I, too, am looking forward to your report on how
well it works.
Suggest checking what's going on with your dB
readings, though. 16 dB is quieter than a bedroom
at night, & likely inaudible to those of us
who have been flying for a decade or two.
Realistic levels expected in the cockpit of a
homebuilt will be between 85 dB (pretty good, but
still loud) & 120 dB (loud rock concert levels
and painful to most of us).
I'd also suggest using the C scale instead of the
A scale. The A scale is very commonly used, but it
presents a very distorted view of the actual sound
level. It radically filters the low end of the
spectrum, and to a lesser extent, the high
frequencies, as well. It will mask the level of
your actual noise exposure, especially at the low
end of the noise spectrum.
Charlie