Yes. The audio quality of land line phones was dictated primarily by transducers. This was by design. The TIA published specs for USA, Canada had their own as w

Yes. The audio quality of land line phones was dictated primarily by transducers. This was by design. The TIA published specs for USA, Canada had their own as well as most other countries. The response of a twisted pair was pretty good over 2 to 4 miles as I recall but for a audio grade (50Hz to 5000Hz) various techniques were used that at the simplest involved coils but there were also active equalizers available for long haul circuits and/or "hi-fi" requirements. Remember DSL lines were/are shipping 1..2Mhz carriers over those same old telco lines. :-) Of course some old trunk lines used paper insulation. Really. Which meant noise went up ... when it rained.