If you’ve been on an airplane in the last few years, you’ve probably seen the Bose QuietComfort noise-cancelling headphones before: they’re a favorite of regular travelers because they’re so good at keeping outside noise out. They’re comfortable, they sound incredible, and the noise cancellation is so impressive that you feel like you’re in your own personal bubble. These headphones are not cheap, but they’re definitely worth the money.
Headphones (or head-phones in the early days of telephony and radio) traditionally refer to a pair of small loudspeaker drivers worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound. Headphones let a single user listen to an audio source privately, in contrast to a loudspeaker, which emits sound into the open air for anyone nearby to hear. Headphones are also known as earspeakers, earphones[1] or, colloquially, cans.[2] Circumaural ('around the ear') and supra-aural ('over the ear') headphones use a band over the top of the head to hold the speakers in place. Another type, known as earbuds or earpieces[1] consist of individual units that plug into the user's ear canal. A third type are bone conduction headphones, which typically wrap around the back of the head and rest in front of the ear canal, leaving the ear canal open. In the context of telecommunication, a headset is a combination of headphone and microphone.
Those who buy either of these headphones are in for a treat. Our reviewer didn’t hold back in their assessment of these cans’ ability to fully realize every detail of a recording, noting their “warm and rigid bass, a midrange that dips close to the ruddy colors of analog tape saturation (without sacrificing an ounce of detail), and a laser tight response up top that helps illuminate vivid clarity and granular instrumental texture across the board.”
The FiiO E17 “Alpin” + AIAIAI TMA-1 or Pro700 Mk2 seem like a mix you’d recommend, but I’m concerned those cans will be uncomfortable for day-long use.  Also I don’t know if that DAC/amp is the best for my style of music/headphones.  Third, some of my techno tracks have stunning vocals, and I don’t want to miss out on those high notes while enjoying the bass.
Impedance: Generally speaking, the lower the headphones' electrical impedance (aka resistance), the easier it is to get higher volume. But here again, the low impedance is no guarantee of high volume capability; other factors can still limit loudness potential. Since many MP3 players have feeble power output -- the iPod is a notable exception -- smart shoppers should check the loudness before purchasing any pair of headphones. To be sure, listen with your player.
The QuietComfort 20 headphones have been around for years and years; and they’re essentailly an in-ear alterative to Bose’s QuietComfort 25. They offer the same great active noise-cancellation that the company is known for, just in a traditional wired and in-ear form factor. The QuietComfort 20 can also be switched to an “Aware” (aka ambient) mode, so you can better hear the world around you.
The QuietComfort 20 headphones have been around for years and years; and they’re essentailly an in-ear alterative to Bose’s QuietComfort 25. They offer the same great active noise-cancellation that the company is known for, just in a traditional wired and in-ear form factor. The QuietComfort 20 can also be switched to an “Aware” (aka ambient) mode, so you can better hear the world around you.
The usual way of limiting sound volume on devices driving headphones is by limiting output power. This has the additional undesirable effect of being dependent of the efficiency of the headphones; a device producing the maximum allowed power may not produce adequate volume when paired with low-efficiency, high-impedance equipment, while the same amount of power can reach dangerous levels with very efficient earphones.

Alternatively, online calculators can be used.[13] Once the sensitivity per volt is known, the maximum volume for a pair of headphones can be easily calculated from the maximum amplifier output voltage. For example, for a headphone with a sensitivity of 100 dB (SPL)/V, an amplifier with an output of 1 root mean square (RMS) voltage produces a maximum volume of 100 dB.


Using headphones at a sufficiently high volume level may cause temporary or permanent hearing impairment or deafness. The headphone volume often has to compete with the background noise, especially in loud places such as subway stations, aircraft, and large crowds. Extended periods of exposure to high sound pressure levels created by headphones at high volume settings may be damaging to hearing;[25][26] Nearly 50% of teenagers and young adults (12 to 35 years old) in middle and high income countries listen to unsafe levels of sound on their personal audio devices and smartphones.[27] however, one hearing expert found in 2012 (before the worldwide adoption of smartphones as the main personal listening devices) that "fewer than 5% of users select volume levels and listen frequently enough to risk hearing loss."[28] The International Telecommunication Union recently published "Guidelines for safe listening devices/systems" recommended that sound exposure not exceed 80 decibels, A-weighted dB(A) for a maximum of 40 hours per week.[29] The European Union have also set a similar limit for users of personal listening devices (80 dB(A) for no more than 40 hours per week) and for each additional increase of 3-dB in sound exposure, the duration should be cut in half (83 dB(A) for no more than 20 hours, 86 dB(A) for 10 hours per week, 89 dB(A) for 5 hours per week and so on. Most major manufactures of smartphones now include some safety or volume limiting features and warning messaging in their devices.[30][31] though such practices have received mixed response from some segments of the buying who favor the personal choice of setting their own volume levels.
Expensive: Audiophile-grade headphones can cost anywhere between $130 and $2,000. Headphones in this price bracket are no joke: they create impressive soundscapes, are robust enough for use in a recording studio, and they’re just plain beautiful. If you need a pair of headphones for critical listening, or you simply want the best headphones around, it’ll cost you.
In-ear headphones are like earbuds but are an upgrade to them. These headphones fit into the wearer's ear canal and stay in place with the use of foam or rubber tips. These tips are available in custom sizes so they can fit each individual wearer. When a proper fit's achieved, in-ear headphones reduce outside noise and deliver sound quality at about the same level as over-ear and on-ear headphones.
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