Convert Centibels to Millinepers

Convert Centibels (cB) to Millinepers (mNp) instantly and accurately.

Conversion Formula

mNp = cB × 11.51292546

About Centibels

The centibel (cB) is one-hundredth of a bel (1 cB = 0.01 B = 0.1 dB), equal to exactly one-tenth of a decibel. This resolution is the standard for clinical audiometry and professional audio equipment. The pure-tone audiogram (ISO 8253-1, ANSI S3.21) records hearing thresholds at 5 dB (50 cB) steps for screening, but research audiometers adjust in 0.25 dB (2.5 cB) steps for precise threshold measurement. The human just-noticeable difference (JND) for loudness of a 1 kHz tone at 70 dB SPL is ≈ 1–3 cB (Moore, 2012), rising to 5–10 cB near the absolute hearing threshold. IEC 60268-5 specifications for loudspeakers require frequency response plots with centibel (0.1 dB) resolution. In studio monitor calibration (SMPTE RP 200, ITU-R BS.1116), loudspeaker level matching is verified to within 0.1 dB (1 cB). 1 cB = 0.01 B = 0.1 dB ≈ 0.011513 Np.

About Millinepers

The millineper (mNp) equals one-thousandth of a neper (1 mNp = 10⁻³ Np), representing a level change of (20/ln(10)) × 10⁻³ ≈ 0.008686 dB. In transmission-line theory, the attenuation constant α (Np/m) is expressed in millinepers per metre (mNp/m) for modern low-loss coaxial and twisted-pair cables. Standard single-mode optical fibre (ITU-T G.652.D) has an attenuation coefficient of ≈ 0.2 dB/km ≈ 23.04 mNp/km at 1550 nm. A standard ITU-T hypothetical reference circuit (HRC) of 27,500 km was allocated 13.0 Np total attenuation, averaging about 0.47 mNp/km. The gap between normal hearing (0 dB HL) and mild impairment (25 dB HL) spans ≈ 2,876 mNp, while the JND of ≈ 0.25 dB ≈ 28.8 mNp is resolvable by trained listeners. 1 mNp = 10⁻³ Np ≈ 0.008686 dB = 8.686 × 10⁻⁴ B.

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