Convert Millibels to Millinepers

Convert Millibels (mB) to Millinepers (mNp) instantly and accurately.

Conversion Formula

mNp = mB × 1.151292546

About Millibels

The millibel (mB) is one-thousandth of a bel (1 mB = 10⁻³ B = 0.01 dB), the finest routine subdivision of the bel family in widespread practical use. The AES17-2015 standard for digital audio converter measurement requires frequency response flatness within ±0.01 dB (±1 mB) across 10 Hz–20 kHz for a reference-quality interface. Audiometer calibration (IEC 60645-1, ANSI S3.6) specifies attenuator step accuracy to ±0.1 dB (10 mB) for research-grade psychoacoustic instruments. Modern audio codec chips (ESS Sabre ES9038PRO) specify passband ripple to 0.01 dB = 1 mB. In broadcast loudness metering (EBU R128, ITU-R BS.1770), integrated loudness is calculated at 0.1 LU = 10 mB resolution. IEC 61672-1 Class 1 sound level meters achieve frequency response flatness within ±0.7 dB (70 mB) from 31.5 Hz to 8 kHz. 1 mB = 0.001 B = 0.01 dB ≈ 1.151 × 10⁻³ 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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