Decrease engine volume when canopy is closed

I'm trying to figure out how to decrease the engine sound when the canopy is closed. I've find that when in have a good level for when the canopy is open (loud, but not deafening) closing the canopy doesn't cut the sound enough for me.

Searching the sound definition files I can't find how the engine sound is reduced by the canopy position.

Have you tried checking the box for "hear like in helmet" in the sound options tab?

Have you tried checking the box for "hear like in helmet" in the sound options tab?

Yes, it muffled sound as well, but still the variance between how loud the engine is between open and closed canopy isn't great enough for my liking.

It's a small thing, but I'm like just a little whine in the background with the canopy closed, but much louder with the canopy open. If I have the closed sound levels I like, an active airbase is eerily quiet taxing around with the canopy up.

Not the end of the world, but I'm hoping it's a simple gain variable that I haven't found yet