Can't help you with the sound effects, but 3M makes an elastomeric respirator with a special sound diaphram so it more readily transmits sound wave through the mask.
I've tried placing a mic inside the mask, but it doesn't sound any better than placing it outside of the mask.
I always wear an elastomeric respirator, because: it's more comfortable than a FFP N9 mask; it is more efficient at filtering (N100 or P100); and it is easier to do a seal check on it.
I don't care what it looks like -- any mask looks kind of silly, really. (I'm old enough to remember when they used to laugh at people for wearing a seatbelt in the car, but I wore it anyway.)
>"Hoping good hopes for the new round of boosters..."
We won't know the effectiveness of the bivalent boosters for some time -- they aren't doing any human trials on them before they're released to the general public.
@Pat *does quick image search* Tempting, but the benefits might be outweighed by the trauma of seeing me show up dressed for The Hot Zone.
Hoping good hopes for the new round of boosters...