Guides
Short, sourced explainers on decibels, limits, ear protection and measuring sound.
dB, dBA and dBC: what the letters mean
A decibel is a ratio, not a unit of loudness. The letter after it tells you how the measurement treated low and high pitches, and that can change the number by tens of decibels.
Why two 80 dB sounds make 83 dB, not 160
Decibels are logarithms, so they do not add like ordinary numbers. Doubling the sound energy adds 3 dB; ten times the energy adds 10 dB.
How loud is too loud? Safe decibel levels and times
Hearing damage depends on level and time together. The widely used guide: 85 dBA for 8 hours, with the safe time halving for every 3 dB more.
How loud is too loud for headphones, and for kids?
Personal music players can produce over 100 dBA at the ear. A safe week of listening depends on level: at 80 dBA, 40 hours; at 95 dBA, barely more than one.
Concerts and festivals: how to protect your hearing
Concerts often average around 100 dBA, where NIOSH’s daily limit is 15 minutes. Earplugs made for music keep the sound clear and cut the risk sharply.
NRR vs SNR: what earplug ratings really mean
The number on an earplug pack is a laboratory best case. NIOSH, OSHA and the UK HSE each say to knock it down before relying on it.
How phone decibel meters work, and how accurate they are
A phone can be a useful sound level meter, within a few decibels, if the app is good and the microphone is calibrated. Browser meters are rougher. Here is why.
The loudest sounds ever recorded
From the white bellbird to Krakatoa, the loudest sounds on record, with what was measured, where, and how sure anyone can be.
Fireworks, pets and children: how loud is too loud?
Fireworks are impulses: their peaks at close range can exceed the 140 dB limit for adults. Dogs and cats hear far higher pitches than we do, and fear of fireworks is common.