Is listening daily at an average of 85db safe?

Nemesis,

What matters is the peaks that make up the average level. I suspect the levels you use are OK. I assume you know dB(C) is spectrally pretty flat, whereas dB(A) reflects auditory sensitivity.

I don't understand what 6550c may have read. Acoustic energy impinges on the eardrum, is passed through the middle ear mechanism to the inner ear where displacement along the basilar membrane cause neurons to fire, such firing runs up the auditory nerve, and is represented in the auditory cortex. This, of course, is a simplistic characterization of the process. IIRC, at lower levels than the auditory cortex nerve activity between the two ears is compared for timing information. The hair cells along the basilar membrane can be damaged by excessive noise exposure, and various substances.

db

6550C,

As a grad student in the early 60s I worked at a research center set up to study the effects of noise on man. The work was funded by NIH grants. As a post doc I worked on binaural processing. I have not worked in psychoacoustics for more than 50 years, nor have I read the literature (JASA, etc.). Perhaps the auditory system has evolved since then or acoustic tricks have been invented that are beyond my time.

Although I have not claimed expertise in this field for at least 40 years, IIRC the auditory system pretty much responds to the acoustic events incident upon it. There are limits to temporal resolution, but we perceive acoustic events more or less as they occur.

By "ten dollar words" do you mean basilar membrane and hair cell, the mechanical precursors to the neural firings that are transmitted to the auditory cortex and perceived as sound