Bert Coules wrote:
It's an interesting notion but surely impractical, I'm afraid: quite
apart from the need to boost only higher frequencies, the angling
required would make any shoulder pads a very odd shape indeed.

No. Fresnel mirrors can be of arbitrary external shape, and so could
fit the shoulders in exactly the same way as ordinary shoulder pads.

Modern hearing aids are small, self-contained, hard to spot, very
efficient and even programmable with different frequency responses
for differing conditions. And available free on the NHS. That's
tough competition.

If only all that were true !