I tend to regard the M50 as the minimum for hi-fi listening with no apologies for limitations. But if you have to go cheaper than the usual $125 USD for the M50, the B&O Form2 with a simple bass boost gives a real hi-fi sound, and it should be available for about $100. The Beyer DTX-501P (similar to soundmagic P30) is good for $100, but needs a slight treble boost. The LSTN Fillmore with wood cups is somewhat colored, but still a good listen and good for $100. Below $100 are the Sennheiser PX series – not hi-fi by any means. There are several good IEMs below $100, and Apple Earpods with a Dirac or Accudio Pro player are very hi-fi, and cheap.
Cable dressing and length: Most stereo headphones have just one cable, usually attached to the left earpiece (sometimes called single-sided cabling). Some models -- and all earbuds -- use a Y-cable that connects to both earpieces (double-sided). The actual cable plug, meanwhile, is usually one of two designs: a straight I-plug or an angled L-plug; the latter may be useful if your portable player has a side- or bottom-mounted headphone jack.
Headphones can prevent other people from hearing the sound, either for privacy or to prevent disturbing others, as in listening in a public library. They can also provide a level of sound fidelity greater than loudspeakers of similar cost. Part of their ability to do so comes from the lack of any need to perform room correction treatments with headphones. High-quality headphones can have an extremely flat low-frequency response down to 20 Hz within 3 dB. While a loudspeaker must use a relatively large (often 15" or 18") speaker driver to reproduce low frequencies, headphones can accurately reproduce bass and sub-bass frequencies with speaker drivers only 40-50 millimeters wide (or much smaller, as is the case with in-ear monitor headphones). Headphones' impressive low-frequency performance is possible because they are so much closer to the ear that they only need to move relatively small volumes of air.
The number one rule to understand when embarking on your headphone-search journey is to understand that there is no one headphone to rule them all. Like automobiles, headphones are made for different purposes. You have the supercars, roadsters, SUVs, 4x4s, sedans, to the compacts, and you chose what’s best for your day to day needs. There is no one car that can tackle snow and win races on the drag strip. The sooner you understand this fact, the more money you will save.
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.

Headphones are available with high or low impedance (typically measured at 1 kHz). Low-impedance headphones are in the range 16 to 32 ohms and high-impedance headphones are about 100-600 ohms. As the impedance of a pair of headphones increases, more voltage (at a given current) is required to drive it, and the loudness of the headphones for a given voltage decreases. In recent years, impedance of newer headphones has generally decreased to accommodate lower voltages available on battery powered CMOS-based portable electronics. This has resulted in headphones that can be more efficiently driven by battery-powered electronics. Consequently, newer amplifiers are based on designs with relatively low output impedance.
While the data signal containing Bluetooth audio is compressed, headphone and earphone manufacturers have found ways to enhance the signal to compensate for its deficiencies in a way that even audiophiles can appreciate. We've included some wireless options here, but if you're really keen on cutting the cord, check out The Best Wireless Headphones. And if you want to go completely wireless (with no cord at all connecting the two earpieces), check out The Best True Wireless Headphones—just keep in mind these are about as far from over-ear headphones as you can get.
The WH-1000xM3’s advanced control systems allow you to let in various levels of ambient sound, with advanced features like voice-only mode, which helps filter through vocal frequencies so you can hear your music and the voices around you while blocking out other sounds. Responsive touch controls let you navigate volume, make calls, and play and pause music with ease, all while helping to maintain a clean aesthetic. Best of all, the WH-1000xM3 offer a staggering 30 hours of battery life, providing even heavy users with days of use from a single charge, and have a quick charge feature that allows you to enjoy five hours of listening after just 15 minutes of charging.
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.
Sony’s technologically advanced WH-1000xM3 are the third generation of Sony’s flagship wireless headphones (following the excellent WH-1000xM2 and MDR-1000x models) that offer top-tier noise canceling, excellent quality wireless audio, and plush comfort. This enticing combination earned the model a rare five-star rating in our initial review, and — thanks to a few notable improvements — makes the latest version the best headphones you can buy.
Earbuds have small speakers that rest on the ear canal of the wearer. These are usually much less expensive than on-ear and over-ear headphones and reproduce the sound well. However, outside sounds, such as traffic or power tools, can get past the earbuds and interfere with your enjoyment. Earbuds also don't stay in place very well if the wearer is moving much, such as exercising. These also are lower fidelity than on-ear and over-ear headphones.