Problem is, IRDA requires line-of-sight. That is, your send has to be able to see the receiver. Even a bit of paper between them will kill the connection.
Now, you can scatter the IR waves over a wide direction - but it's not as useful as chucking a phone in your backpack and streaming it to earphones.
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Now, you can scatter the IR waves over a wide direction - but it's not as useful as chucking a phone in your backpack and streaming it to earphones.