He pops on a pair of in-ear earphones and snaps a directional mike on his iPhone, which has an app to amplify and process sound.
“I put the iPhone on the table,” he said. “I point it at whoever’s talking, and I can have conversations with them. Soon we forget the iPhone is sitting there.”
A new version of the directional microphone Mr. Einhorn uses, Blue Mikey, is available for $99.99. One app he uses is soundAMP R, which is $4.99. For earphones, he likes the in-ear Etymotic hf5, at $149.