Headphones connect to a signal source such as an audio amplifier, radio, CD player, portable media player, mobile phone, video game console, or electronic musical instrument, either directly using a cord, or using wireless technology such as Bluetooth, DECT or FM radio. The first headphones were developed in the late 19th century for use by telephone operators, to keep their hands free. Initially the audio quality was mediocre and a step forward was the invention of high fidelity headphones.[3]
Passive noise isolation is essentially using the body of the earphone, either over or in the ear, as a passive earplug that simply blocks out sound. The headphone types that provide most attenuation are in-ear canal headphones and closed-back headphones, both circumaural and supra aural. Open-back and earbud headphones provide some passive noise isolation, but much less than the others. Typical closed-back headphones block 8 to 12 dB, and in-ears anywhere from 10 to 15 dB. Some models have been specifically designed for drummers to facilitate the drummer monitoring the recorded sound while reducing sound directly from the drums as much as possible. Such headphones claim to reduce ambient noise by around 25 dB.
If you’ll mostly be using headphones at your desk, install a headphone hook so you can safely stow yours when you’re not using them. Headphones can be fairly fragile, so it’s important to take care of yours and avoid tossing them around. A headphone hook gives your favorite pair a place to hang and creates a fun conversation piece for your workstation.
Once you’ve got that all order, to put a cherry on top it would be ideal for the amp to play nice with my laptops (PC at work, Mac at home) *and* my *iPhone* 4S.  I haven’t found a headunit that works with PCs and iDevices.  If one doesn’t exist it would be a big plus for the amp to include inputs so I can get digital sound out of my iPhone (with the Pure i20 or its ilk) and into my headphones.
I think it’s fair to compare the Grados and HD598, but the M50 is very different and seems not to fit in that comparison. The DT770 is a better comparison to the M50, although the 770 is a better more expensive item. A long time ago I had a Grado 325 and a Sennheiser HD565 – very similar, very enjoyable. Today for that type of sound I might choose the Soundmagic HP100.
Released in 2017, the Bose SoundWear Companion is a different kind of wireless headset. It doesn’t have any earcups or earbuds, but instead it sits around your neck adn has speakers that shoot sound up towards your ear — it’s essentially a portable speaker that sits around your neck. It’s water-resistant, so you can technically work out while wearing it, but it’s really designed for the person who works at home. It’s comfortable enough to wear for lengthy periods of time, but it also has excellent built-in microphones and works great as a speakerphone.
Marketed claims such as 'frequency response 4 Hz to 20 kHz' are usually overstatements; the product's response at frequencies lower than 20 Hz is typically very small.[23] Headphones are also useful for video games that use 3D positional audio processing algorithms, as they allow players to better judge the position of an off-screen sound source (such as the footsteps of an opponent or their gunfire).
Dale: The examples listed above are good general rules, but there also are so many exceptions and in-betweens that it also could be better to understand what is needed for your music, so you can narrow the search to the most appropriate headphones. For example, you may have heard that Classical music is a particular genre, but within that ‘genre’ are many very different types of music. Chamber music or pipe organ music may benefit from a headphone that’s highly detailed in the treble (a headphone that some users might say is bright), while harpsichord music and music that has a lot of strong trumpet sounds might be better served with a more rounded or softer treble.
Dale: The examples listed here are good general rules, but one thing to keep in mind is in the mid-to-lower price tiers, open-back headphones aren’t nearly as common as the closed types. The smaller list of choices, and the more limited reviews of those items, could make getting a perfect fit more difficult. Sound stage and openness are often given as the advantage of the open-back types, but it’s just a general rule and some closed-back headphones excel at those properties. An important thing to consider is the music itself, since sound stage and perspective varies widely in different recordings.

Frequency response: Frequency-response specifications in full-size loudspeakers are generally pretty useless in predicting sound quality, but headphone frequency-response numbers are even worse. Manufacturers have routinely exaggerated frequency-response figures to the point that they're irrelevant. Even the flimsiest, cheap headphones routinely boast extremely low bass-response performance --15Hz or 20Hz -- but almost always sound lightweight and bright. Generally, bass buffs will be happier sticking with larger 'phones.

This is better than I thought it would be. Worst case is the T51p won’t have the excitement of the more “V”-shaped headphone sounds, but you’ll hear more of what’s actually in the recording. The more neutral headphones are most often a little bright (that’s what most users say), and can irritate on electronic and improvised music, but the T51p didn’t show any of that with these 3 tracks.
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.
Sports headphones are among the most popular types of headphones and the best ones are now wireless. Sweat-resistant or even totally waterproof, they can be used at the gym or for running or biking. Some are have an open or semi-open design to let some sound in for safety reasons (so you can hear traffic noise). However, other models have a sealed, noise-isolating design.
Unlike with other codecs, AAC test signals from Android phones like the Huawei P20 Pro, LG V30, and Samsung Galaxy Note 8 all vary wildly. Though we can’t definitively say why each Android device seems to handle AAC encoding differently, the fact of the matter is that only Apple can do it well. We suspect some of the power saving features baked into the Google ecosystem’s varying hardware has consequences for audio playback. Nowhere is this more apparent than Huawei’s power-sipping P20 Pro, which seems to cut out at around 14.25kHz.

Smaller earbud type earpieces, which plugged into the user's ear canal, were first developed for hearing aids. They became widely used with transistor radios, which commercially appeared in 1954 with the introduction of the Regency TR-1. The most popular audio device in history, the transistor radio changed listening habits, allowing people to listen to radio anywhere. The earbud uses either a moving iron driver or a piezoelectric crystal to produce sound. The 3.5 mm radio and phone connector, which is the most commonly used in portable application today, has been used at least since the Sony EFM-117J transistor radio, which was released in 1964.[9][10] Its popularity was reinforced with its use on the Walkman portable tape player in 1979.