μbar
microbar
Pressureexact by definition
The microbar is 10⁻⁶ bar, exactly 0.1 pascals, and identical to the barye of the CGS system. It is the traditional reference unit of acoustics: older microphone sensitivities are given in volts per microbar, and the pre-SI sound pressure level reference was 1 μbar rather than today's 20 μPa.
Watch out: A microphone sensitivity in dB re 1 V/μbar and one in dB re 1 V/Pa differ by 20 dB. Converting old datasheets without accounting for that is a factor-of-ten error in every level that follows.
| 1 μbar | 0.0001 kPa |
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