Application guide
How Loud Is a Concert in Decibels
The answer depends almost entirely on where you are standing, and this is the one situation where a phone microphone is most likely to give you a number that is too low rather than too high.
Free to download. The clipping flag is in the free version.Typical levels
Position changes the answer by 20 dB or more
Reported figures for amplified live music run from roughly 90 to 100 dB toward the back of a large room, and 110 to 120 dB directly in front of the speaker stacks. Because the decibel scale is logarithmic, a move from the barrier to the mixing desk is not a small improvement, it is the difference between a level you can stand for minutes and one you can stand for an hour.
Ranges as reported by Miracle Ear and the Hearing Health Foundation. Your room and your position will differ, which is the reason to measure rather than to look up.
The bands the app uses to label a reading, in dB(A): Calm from 0, Quiet from 30, Conversation from 50, Busy street from 70, Loud from 90, Concert from 100.
Time, not just level
How long the recommended limit lasts
The NIOSH criterion is 85 dBA for eight hours with a 3 dB exchange rate, so every 3 dB louder halves the allowed time. Applied to a concert that gives you: about 15 minutes at 100 dBA, about 7 minutes at 103 dBA, and under two minutes at 109 dBA. Below 80 dBA there is no practical limit, and dB Decibel says so rather than printing a countdown.
This arithmetic is why earplugs change the evening rather than ruin it. Concert earplugs are commonly sold with a rated attenuation somewhere between 15 and 30 dB, and even the low end of that range moves a 105 dBA room into territory measured in hours rather than minutes.
The full arithmetic is set out in the workplace noise guide.
The honest part
At the barrier, a phone lies low
Why the number falls short
A microphone has a ceiling. Once the sound pressure exceeds what it can represent, the waveform is cut flat at full scale and every level computed from it is lower than reality. Reported saturation points for phone microphones sit in the region of 100 to 105 dB, which is exactly where a concert lives.
So the failure mode at a concert is not exaggeration. It is a reassuringly moderate number for a room that is not moderate.
What dB Decibel does about it
The app inspects the peak sample of every audio buffer. Once three buffers in a row sit at or above 0.99 of full scale it latches a clipping flag, and clears it the moment a buffer drops back below.
A clipping flag is not a measurement. It is the app telling you that this room is past what your phone can measure, and that the figure on screen is a floor rather than an answer.
Measuring at a show, practically
- Measure where you are actually standing, and measure again if you move. One reading for a whole night describes nothing.
- Take the phone out of its case, and hold it away from your body rather than in a pocket. Clothing is an attenuator.
- Keep a finger off the bottom edge, where the primary microphone is.
- Watch for the clipping flag. If it latches, note it. The honest entry is "above what the phone could measure", not a number.
- Use Leq for the set rather than the peak. A single firework of a snare hit is not what your ears spent the evening in.
What this app is not. Readings are approximate (±dB) and come from an uncalibrated phone microphone. dB Decibel is an environmental sound measurement tool. It is not a certified sound level meter, not a dosimeter, not hearing protection and not a medical device, and it is not suitable for occupational, regulatory or legal compliance. That wording is taken from the disclaimers inside the app itself. The app cannot tell you whether your hearing was harmed. If you have ringing or dullness that lasts beyond the next day, see an audiologist.
Get the app
Take a real reading at the next show
Live dB(A) with peak hold, Leq for the whole set, and the clipping flag that tells you when the room has outrun the microphone. All of that is in the free version. Octave bands and the spectrum analyzer, if you want to see where the energy sits, are part of the one time Pro unlock.
Free to download. iPhone, iOS 18 or newer. Optional one time Pro unlock, no subscription.Keep reading