How are you hearing no difference?

I remember there being some leather versions of those "ear extenders"

Was I not the first? Ortho Ears was going to be my first product. They were based on Spock Halloween ears. Which I think is a smart look. That was 25 years ago.

Funny that this was mentioned. The hearing in my left ear is worse than my right. As I was learning about speaker position and listening position etc I cupped my hand behind my left ear and it made a big difference in the size and shape of the sound stage. But it did have a hollow 'sea-shell' quality to it so I tried different hand shapes and was able to eliminate that.

I'm glad no one saw me doing this...my wife already has plenty of reasons to have me committed. 

Anyway, this worked but is very impractical. Also, with a little more time and effort I was able to balance things out with minor adjustments to speaker and listening chair placement. So now I appear semi-sane while listening.

The cupped-hands technique definitely yields a "sea-shell" effect.
Closing the eyes always improves aural acuity.
Removing eye-glasses does too.
Still trying to prove to my wife I'm semi-sane also...

Act chew ally the cupped hands improves dynamic range, especially for systems that lack dynamic range, and loudness, i.e., a better antenna, but the down side is it impacts soundstage. Once your system can perform dynamically, e.g., room acoustics treatments, you’ll discover the cupped hands doesn’t do much at all. Recordings are made with human ears in mind, not Mr. Spock’s. You’re not hearing the rear reflections since the hands block them.