[kosciusko51]

https://www.hearingaidmuseum.com/gallery/Non-Electric/EarTrumpets/Short%20Trumpets/info/germanovalpocket.htm

[kosciusko51]

https://www.hearingaidmuseum.com/gallery/Non-Electric/EarTrumpets/Short%20Trumpets/info/megaphone.htm

[DiogenesLamp]

Last time I saw this topic discussed, someone posted a picture of a much more rectangular ear horn that looked more like a cell phone.

I'm sure with a little effort, that same picture could be found.