Thank you, Paddy and Bob.
I don't have any panel yet. Most likely it will be a panel from Stein.
On DA40 it does not matter where the vents are pointing or what the height of a pilot is - they are just noisy. Of course, if they point directly to my mike, then it is worse.
Just by looking at the schematics of how they are done on the -10 (I maybe very mistaken), it is a direct pipe from opening on the side of a fuselage to the vent. So, they should be noisy. What Paddy says, is what I think it is going to be.
On DA40 one solution is to cover part of the intake opening on the fuse. This reduces the amount of air, and the noise. I don't like that.
I'm wondering if there is anything that can be done for RV-10.
I'm planning to install overhead console and route rear vents through it. I think that because air will pass through more distance and elbow and corners, the overhead ones will not be an issue.
RV-10 - build in progress