Low-frequency phase shift accumulates massively across every stage of the signal chain

Evidence

In the recording and reproduction of bass frequencies there is an accumulation of phase shift at low frequencies that arises whenever a high-pass filter characteristic is inserted into the signal path. It happens at the very first step, in the microphone, then in various electronic devices that are used to attenuate unwanted rumbles in the recording environments. More is added in the mixing process, storage systems and in playback devices that simply don’t respond to DC. All are in some way high-pass filtered. One of the most potent phase shifters is the analog tape recorder. Finally, at the end of all this is the loudspeaker which cannot respond to DC and must be limited in its downward frequency extension. I don’t know if anyone has added up all of the possible contributions, but it must be enormous. Obviously, what we hear at low frequencies is unrecognizably corrupted by phase shift. — Toole, Floyd E, Sound reproduction- the acoustics and…, 975

Categorization

• QUESTION: The author openly wonders if anyone has summed the total bass phase shift; a back-of-envelope accounting would be a nice quantitative follow-up.
• XREF: Pays off the earlier 7.0-7.4 rating discussion: even perfect transducer phase is swamped by upstream accumulated phase the speaker cannot correct.