# How loud a sound would need to be to wake someone up?

I have been researching about this and it looks like the term would be auditory arousal threshold. Imagine you fall asleep while listening to music with earbuds. Out of a sudden, the device starts playing really loud music (let´s say 40 dB higher compared to what you were listening). This sound would be quite loud that it would damage your ears. My question is, is there any study showing which would be the minimum dB level of a sound that would make you wake up (and, well, remove the earbuds)? I would assume this would depend on the frequency of the signals as well. But, what about the age of the person?

• I don't think this is generally answerable with a single value for all people. The answer would vary from "not very loud" for light sleepers to "impossibly loud" for those who are completely deaf. – kmm Sep 19 '18 at 14:16
• Yes, I understand what you mean. But I was expecting something like an offset that would be a general norm for most people. Let´s say: Subject A has no hearing loss and we could say they would wake with a 90 dB sound. Subject B has a hearing loss of 20 dB and therefore they would need 110 dB to wake up in the majority of cases. Let´s assume hearing loss is flat and the sound is white noise for simplicity. I have also read that the brain can adapt as well and if they are accustomed to white noise during the day, it might not wake them up. – the_moon Sep 19 '18 at 14:30
• Can we say no more damage can be caused to the ear when the threshold is exceeded an damage has been already caused? Let´s say a person with no hearing loss, according to OSHA, would not get their ears damaged if they do not listen to 90 dBA for more than 8 hours. If this limit has already been exceeded and the subject has hearing loss, can we say instead of 90 dB, they can be exposed to 90 dB + Offset for 8 hours now? – the_moon Sep 19 '18 at 14:34
• It's not just about hearing loss. Your threshold for wake up is going to depend on how tired you are, the nature of the sound, what stage of sleep you are in, other personal differences, etc etc. From an engineering perspective, you need to consider the risks of failure: you will want a different level of sound if wake-up is very necessary (i.e., fire alarm) versus if it's okay to miss some % of the time. – Bryan Krause Sep 19 '18 at 16:30
• Humans are not standardized components, which is what makes human factors engineering so hard. 80 percent of children between the ages of 2 and 13 did not wake up from a standard issue alarm. – Charles E. Grant Sep 19 '18 at 19:39