Thanks Bill. I'd like to identify the sources of the major noises, so all you guys keep it coming. You musicians out there certainly know the difference between a hard room and a soft room. I'm wondering how much hard interior surfaces have to do with perceived noise. Can't do anything with all the windows, but everything else can be softened up somehow. If there's a clear choice between quiet and wood chipper loud I'd spend 20 pounds in a heartbeat. There's so much ooomph in the 10 and other places to save weight that I think it's worth it.
Dave,
I was an audio engineer and an early adopter of TEF and LE/DE recording studio design in Nashville early in my career.
While it would be nice to carry those principals to our RV interiors, the physics just aren't there. An acoustic low frequency trap would be much too large for aircraft.
The insulating foam is great for insluation, but for sound, it's only going to attenuate higher frequencies. As a side consequence, most of the insulating products that look like black foam will generate some pretty nasty gases if heated up. (See Dan H's threads for more details).
Over the last five years, I've had the opportunity to ride in many RV-10s. I don't want to put any of the owners on the spot, so I'm not going to mention any names. Some of the RV-10s were built to plans with no insulation to the other extreme with every nook and cranny stuff with insulation.
The bottom line is that, at least for the RV-10, insulation does make a difference for both acoustics and thermal protection. I haven't taken my test gear up to make any measurements, but the differences are quite apparent. None are perfectly quiet, since there really is no effect method to attentuate those lower frequencies produce by the fan up front.
The RV-10s that seem to be quieter all have had some common denominators. All have had interior panels, like those from Aerosport Products, with insulation between the side walls and the interior panel, as well as underneath the floor and in the tunnel.
Yes, these aircraft probably did gain 20lbs or so with their interiors. While they aren't perfectly quiet, you can carry a normal convesation in them. Naturally, with a decent headset, noise is almost completely eliminated.
As with anything with RVs, YMMV depending on the materials used. Please ensure that you understand what are the traits of the materials that you used, should they be exposed to flames or excessive heat.
bob