By Don Lindich
Week 20, 2016
Q. You recently wrote about amplifying sound through headphones to drown out airplane noise. It would have been helpful for you to point out that high volume levels can damage hearing. Wouldn’t some kind of noise-cancelling headphones be a better and safer recommendation?
A. I received several emails from readers concerned about the dangers of hearing loss. Excessively loud, damaging sound is not what I had in mind when I wrote the column about headphone amplifiers. I was focusing on overcoming the shortcomings of equipment, not “cranking up the sound” and I should have pointed that out when I wrote the column.
Different models of headphones produce different amounts of volume for a given electrical input. A modest 3 dB volume increase requires doubling the amplifier power to the headphones, and portable devices do not have much power to begin with. If you pair inefficient headphones with a portable device having weak power output, you may not be able to achieve satisfying volume levels even in quiet conditions. (There are many headphones, such as planar-driver models, that can’t be driven by a portable device at all.) A headphone amplifier may provide the necessary power increase to provide satisfying, distortion-free sound. When I answered the question it was this modest bump in volume I had in mind, not playing so loud to risk hearing damage.
There was a part of my email exchange with Joan C. that never made the column. As we discussed her situation she said, “I am using cheapo earbuds… one set for me, one set for my husband, with a splitter.” Driving two earphones with a single tablet explained why the volume was not acceptable, and when I replied personally I recommended The M Audio amplifier with two ports to solve her problem. I should have included more about her situation in the column, but I was more focused on headphone amplifiers themselves rather than the splitter, since splitters are not commonly used.
Other solutions are noise-cancelling headphones, as you suggested, as well as better isolation from the outside world. If you check out my “Noise-cancelling headphones on a budget” feature at http://tinyurl.com/cheapnch you can find good quality noise-cancelling headphones for as little as $49.95. If you are using earbuds, Comply Foam tips will give you a more comfortable and secure fit, along with better isolation and better sound quality. There is a lot of material science behind Comply Foam that makes it more than just different foam for your earphones. I’ve used Comply myself and highly recommend it. http://complyfoam.com
In closing, I would like to remind readers to be careful with their hearing, as hearing loss can occur quickly when exposed to high volumes. In the column I explained that 99 decibels of volume per watt of input is typical for most headphones. Please note that decibels per watt is simply an industry standard measurement of headphone sensitivity, and 99 decibels is not a recommended or safe volume level. I will be careful about this when I discuss equipment in the future, and as always I trust that when I recommend something, you will not use it to harm yourselves!