Noise from Shaving
About 10 years ago I started using an electric shaver. An electric shaver is more convenient to use as it doesn’t require any soap, foam, or water. It is also almost impossible to cut yourself properly with an electric shaver which is a major benefit for anyone who’s not particularly alert in the morning. Generally my experience of electric shavers has been good, although the noise is quite annoying.
Recently a friend told me that an electric shaver is as noisy as a chain-saw. Given the inverse-square law and the fact that the shaver operates within 1cm of my ears that sounds plausible. So the risk of hearing loss is a great concern. Disposable ear plugs are very cheap and they can be used multiple times (they don’t get particularly dirty while shaving or get squashed in the short time needed to shave). So for a few weeks I’ve been using ear plugs while shaving which reduces the noise and presumable saves me from some hearing damage – although after 10 years of using electric shavers I may have already sustained some damage.
According to Cooper Safety their ear plugs reduce noise by 29dB,  I presume that the cheap ones I bought from Bunnings would be good for at least 15dB.
According to Better Hearing Sydney the noise from an electric shaver is typically around 90dB, less than the 100dB that is typical of a chain-saw . So if my ear-plugs are good for 15dB then they would reduce the noise from a typical electric shaver to 75dB which is well below the 85dB that will cause hearing damage. Given that the noise from a typical shaver is only slightly above the damage threshold it seems that I might not need particularly good ear-plugs when shaving.
A quick scan of shaver reviews indicates that the amount of noise differs by brand and technology. The Hubpages review suggests that rotary shavers tend to make less noise than foil shavers , but I’m sure that it varies enough between brands that some rotary shavers are louder than the quietest foil shavers. It seems that the best thing to do when buying a new shaver would be to go to a specialised shaver shop (which has many models on offer) and get the staff to demonstrate them to determine which is the quietest. If a typical shaver produces 90dB then it seems likely that one of the more quiet models would produce less than 85dB.
Another item on my todo list is to buy a noise meter to measure the amount of noise produced in the places where I spend time. There are some Android apps to measure noise, I’m currently playing with the Smart Tools Co Sound Meter  which gives some interesting information. The documentation notes that phone microphones are limited to the typical volume and frequencies of human voice, so my Galaxy S3 can’t measure anything about 81dB. My wife’s Nexus 4 doesn’t seem to register anything above 74dB. Additionally there is some uncertainty about the accuracy of the microphone, there is a calibration feature but that requires another meter. Anyway the Sound Meter app suggests that my shaver (a Philips HQ7380/B) produces only 71dB at the closest possible range – and drops down to 67dB at the range I would use if I grew sideburns.
Getting a proper noise meter to protect one’s hearing seems like a good idea. An Android app for measuring noise is a good thing to have, even though it’s not going to be accurate it’s convenient and will give an indication.
When buying a shaver one should listen to all the options and choose a quiet one (I might have got a quiet one by luck).
Sideburns seem like a good idea if you value your hearing.
-  http://www.coopersafety.com/NoiseReduction.aspx
-  http://www.betterhearingsydney.org.au/content/view/46/53/
-  http://tinyurl.com/ojxfx9t
-  https://play.google.com/store/apps/details?id=kr.sira.sound