to chacham and sam2 and others : all what you are proving in your quotes is that this is a modern addition to the minhag. simple question: why don’t we pasken (as we do) that, in aveilus (real aveilus….) “holchim achar hameikil”.
Just because you are bringing me a slew of late acharonim that emphasize this new issur doesn’t answer the question.
“Kli shir” (or kli neginah) means exactly that- an actual instrument. Is radio or CD’s an actual instrument? No.
“Hatokea betoch habor” (echo) is not “jotzei’. why should we say that a recording- through electronic waves- is kli shir?