[kalee20]

It's ironic that old radios have crummy treble yet transmissions at the time were not curtailed in the AF upper frequency response. Argos's point of detector filtering is dead right - and with 125kHz IF superhets you do need bigger-valued capacitors to reduce IF breakthrough anyway. Whereas post-war, we have better speakers, 470kHz IF as standard, everything we need for a response to 10kHz-plus... and the transmitters chop off at not much more than 4.5kHz!