I understand the basic process of ANC in headphones and earphones. But when an pair of earphones says “42 dbs” of noise cancelling, does it mean sounds louder than that, say 50 dbs, will sound as loud as 50 dbs or 50 minus 42 dbs?
In: 10
42 Db attenuation means about 95% of the energy of the sound should be cancelled out (making assumptions here).
Decibels are an attenuation factor – think of it like SPF sun screen.
WhatYouHeard = “ActualSound minus 42 Db”
– which is really “ActualSound times 0.008”
Tricky bit a Db is it’s a **relative** measure, at least most of the time.
DbA vs DbB vs DbSPL (Sound Pressure Level) vs plain-old Db.
– https://en.wikipedia.org/wiki/A-weighting
– DbSPL assigns a value of 20 micropascals to equal 0 DbSPL
– Micro Pascal is 1 millionth of a Pascal https://en.wikipedia.org/wiki/Pascal_(unit)
– Pascal is a derive SI unit based on kg / (meter x second)
Clear as mud?
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