Insights into the kind of crap 78-rpm records were made of, and other scarce technical infos.
If you’re not sure what ‘a record’ is, or haven’t ever seen one, you’re excused.
Oh, and by-the-way, 78 is the approximate number you get when you rotate a 46-tooth gear with a 3600 rpm motor. (60 cycles per second.)
Further wisdom such as this is found by the ton here: http://www.78rpmrecord.com/links.htm
You call it a warm sound.
I call it a low-pass filter.