decibelio

Decibelio is the term used in several Romance languages, notably Spanish and Italian, to denote what English speakers call the decibel. It is a unit of measurement for ratios, most commonly used to express sound levels, electrical power, or other quantities that vary over many orders of magnitude. The decibelio is defined as one tenth of a bel, and because it is logarithmic, it converts multiplicative factors into additive increments. The bel is named after Alexander Graham Bell.

Because a decibelio is a relative unit, it requires a reference level. In acoustics the most common form is sound pressure level (SPL) with reference p0 = 20 µPa in air; Lp = 20 log10(p/p0). For power quantities, Lw = 10 log10(W/W0) with W0 = 1e-12 W/m^2. For electrical signals, L = 20 log10(V/V0) when impedances are equal.

Decibelio values are context-dependent and may be weighted. A-weighting (dBA) approximates human hearing sensitivity. Typical levels: 0 dB SPL is near the threshold of hearing; 30-40 dB is a quiet room; 60 dB is normal conversation; 85 dB is the common exposure limit for eight hours; 100-110 dB are very loud such as live concerts; 120-130 dB is pain threshold.

In technical writing, the term decibelio is used primarily in Spanish- and Italian-language sources; internationally the unit is still the decibel (dB). Standards from IEC and ISO specify methods for measuring SPL, weighting, and reference values.