The outer shells of in-ear headphones are made up of a variety of materials, such as plastic, aluminum, ceramic and other metal alloys. Because in-ear headphones engage the ear canal, they can be prone to sliding out, and they block out much environmental noise. Lack of sound from the environment can be a problem when sound is a necessary cue for safety or other reasons, as when walking, driving, or riding near or in vehicular traffic.[19]

That amp, if in good working condition, has 100 times the potential sound quality that those 2 headphones can play. You could improve the sound somewhat with a careful EQ, since the Marantz will have power reserve to spare. But I’d try to find a better headphone, and there are some bargains out there. If I were suggesting an ortho, I’d say get the lower price Mad Dog, which will give you great audiophile sound with the Marantz.

Noise cancellation: Noise-cancelling headphones play specific tones, much like white noise, to cancel out all of the sound around you and allow you to enjoy your music uninterrupted. Noise-cancellation is an active process, so headphones with this feature require batteries. If you’re a frequent flyer, or if you’ve got a noisy commute to work each day, you’ll love noise-cancelling headphones: they’re fantastic at keeping the cacophony of the outside world at bay.

That depends on what you’re using them for and how much you’re willing to spend. At the high-end, over-ear and in-ear headphones can both perform fantastically. For those of us not willing to spend thousands on headphones, over-ear headphones typically offer better bass response and a bigger soundstage, but in-ear headphones are significantly more portable and convenient — especially wireless earbuds.
Pairing high sensitivity headphones with power amplifiers can produce dangerously high volumes and damage headphones. The maximum sound pressure level is a matter of preference, with some sources recommending no higher than 110 to 120 dB. In contrast, the American Occupational Safety and Health Administration recommends an average SPL of no more than 85 dB(A) to avoid long-term hearing loss, while the European Union standard EN 50332-1:2013 recommends that volumes above 85 dB(A) include a warning, with an absolute maximum volume (defined using 40–4000 Hz noise) of no more than 100 dB to avoid accidental hearing damage.[14] Using this standard, headphones with sensitivities of 90, 100 and 110 dB (SPL)/V should be driven by an amplifier capable of no more than 3.162, 1.0 and 0.3162 RMS volts at maximum volume setting, respectively to reduce the risk of hearing damage.
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.
The WH-1000xM3’s excellent noise-canceling technology ranks second only to the Bose QC35 II, from the brand that has long dominated the market in terms of sheer noise-blocking abilities. That said, the Sony cans sound much better than the new bass-forward Bose option, and offer numerous features that help to create a much better overall experience.
However, we also move up to high-resolution audio files, as well as a wide variety of sources, including plugging in directly to a PC or Mac, using USB DACs (digital-to-analog converters), and employing high-quality, dedicated portable players and amplifiers. Finally, we compare the headphones to some of our go-to models, both in their class and price point, as well as a level or two above to find out if they can punch above their weight.
The E25BT didn’t score quite as high for audio quality as other models on this list, and it lacks some features you’ll find on certain other models, such as water resistance and extended battery life. But if you want a pair of wireless headphones that provide decent sound at a fraction of the cost of its competitors, the E25BT is an appealing option.
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.
Hearing risk from headphones' use also applies to workers who must wear electronic or communication headsets as part of their daily job (i.e., pilots, call center and dispatch operators, sound engineers, firefighters, etc.) and hearing damage depends on the exposure time. The National Institute for Occupational Safety and Health (NIOSH) recommends sound exposure not exceed 85 dB(A) over 8 hour work day as a time-weighted average.[35] NIOSH uses the 3-dB exchange rate often referred to as "time-intensity tradeoff" which means if sound exposure level is increased by 3 decibels, the duration of exposure should be cut in half. NIOSH published several documents targeted at protecting the hearing of workers who must wear communication headsets such as call center operators,[36] firefighters,[37] and musicians and sound engineers.[38]

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.
Portability can mean many things, such as appearance in public, having a secure fit so the headphone doesn’t shift off of your ears, amount of isolation from ambient noise (including active noise canceling), whether the headphone can be worn around the neck when not listening or it requires a carry case, and when extra amplification is required, whether a suitable amp can be found that’s OK to carry along with the portable music player.
That amp, if in good working condition, has 100 times the potential sound quality that those 2 headphones can play. You could improve the sound somewhat with a careful EQ, since the Marantz will have power reserve to spare. But I’d try to find a better headphone, and there are some bargains out there. If I were suggesting an ortho, I’d say get the lower price Mad Dog, which will give you great audiophile sound with the Marantz.

hum..I see your point…The big concern to me is that, since I don´t live in USA, everytime I order a pair of cans if I don´t like it I sell it….That´s the reason I will order starting with the most popular brands… it will be easier for me to pass a senn than a superlux, for instance. You know what I mean? Since you have mentioned 598 and HP100, can you please tell me who wins in terms of soundstage, spaciousness, and good separation?
Today they are typically used only in in-ear headphones and hearing aids, where their high efficiency and diminutive size is a major advantage.[20] They generally are limited at the extremes of the hearing spectrum (e.g. below 20 Hz and above 16 kHz) and require a better seal than other types of drivers to deliver their full potential. Higher-end models may employ multiple armature drivers, dividing the frequency ranges between them using a passive crossover network. A few combine an armature driver with a small moving-coil driver for increased bass output.
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]