The 'cone' you refer to is a horn, and is in essence the reverse principle of those early wind up, horn gramaphone players.The horn was there to capture the sound and transmit it to a cutting needle, rather than vice versa. There was no magnetic media in those days (be it recording tape or hard drives) and the sound had to be recorded 'directly' to the final medium. Attempts of mass production made the musicians play (and play again and again) into a line of horns, each in turn driving the cutting needle. What is interesting is that since these horns were physically spaced, if you took a recording from the right side of the line and one from the left side of the line you would end up with 2-channel stereo- sort of like a crude Blumlein pair. But there was no way of synchronizing the playback as speeds and speed variations varied widely.
Magnetic tape made the recording process much more manageable as it could be used over and over to generate new 'records' instead of the band having to play the same piece to a very limited number of horn recorders time and time again. But it still represented an additional link in the signal path.
I think you would be very suprised to hear how 'vital' some ancient 78-rpm shellac records sound through a wind up horn-player even allowing for the tonal inaccuracies due to the horn.
Ron
Dum spiro audio
Dum audio vivo
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