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.

Although some headphones available are wired, many more are available that are wireless, and use Bluetooth to enable your music to be heard, even if the stereo or other device is several feet or even a few rooms away. Wired headphones deliver superior sound quality to wireless and Bluetooth because there's no chance of picking up interference from other devices, which sometimes happens with wireless headphones. In addition, wired headphones have no batteries to power them, so there's no chance of interruption should the batteries wear out.

Historically, many headphones had relatively high impedance, often over 500 ohms so they could operate well with high-impedance tube amplifiers. In contrast, modern transistor amplifiers can have very low output impedance, enabling lower-impedance headphones. Unfortunately, this means that older audio amplifiers or stereos often produce poor-quality output on some modern, low-impedance headphones. In this case, an external headphone amplifier may be beneficial.
The iPhone will drive the headphone fine and make a very nice sound, but the amp will make a big improvement in harmonic extension and soundstage. Use the amp whenever possible. Both Headfonia and I concur that the E07k is a great amp, and probably the best thing you can get for up to twice the price. I’m familiar only with the E07k, the E17, and the E12. I think the E07k beats the E17 (and both are also USB DACs), while the E12 is just an amp, and has a darker sound but with more power for inefficient headphones. The Philips is not inefficient.
hi? i want to ask a question. Im a complete newbie on the audiphilic side so i red on a site that the more the impedance is higher a headphone amp is requierd and less the impedance a headphone amp is not that much requierd cause the headphones with less impedance are made for portable players. Now let me get to the point im using cheap headphones the philips sbc hp250 they are old about 5 years and sound ok but i want to replace them so i use them mostly for listening to hours of music and i am also a musician so would it make a diference if i would buy a behringer headphone amp http://www.amazon.com/Behringer-HA400-4-Channel-Stereo-Headphone/dp/B000KIPT30/ref=sr_1_6?ie=UTF8&qid=1379715994&sr=8-6&keywords=behringer+amplifier and amplify those headphones would they play better cause now im having them plugged on a intergrated via vinyl soundcard http://www.via.com.tw/en/products/audio/codecs/vt1708s/. and they sound shitty on full volume. I am considering to buy new full size headphones and im willing to give max 80 euros for them so for the start i just want them to be loud but i want a clear sound at high volume levels. To be more specific i want a clear sound that is balanced in the lows mids and highs but not distorted and the lows should not be too much overpowered. I was sniffing around your site and found some sennheiser hd 202 ii they are not even close to 80 euros but i heard they sound great would they be better than these philips headphones and what other alternatives would you suggest me for max 80 euros
If you just want to block out sound without active noise cancellation, good over-ear headphones will naturally do that to some extent. This is called noise isolation, and it simply works from the earcups forming a good seal over your ears to prevent outside noise from getting in. It's not as effective, but it's less expensive than active noise cancellation and doesn't require power.
There’s a lot of debate in the headphone world about wireless audio. Wireless standards like Bluetooth are capable of making music sound great, but because Bluetooth relies on data compression, it will never sound quite as good as a wired connection. The big question is, with the improvements in Bluetooth, can anyone tell the difference anymore between Bluetooth audio and wired audio? We’re skeptical that the difference is meaningful, so here’s our best advice: if you’re an audiophile who cares about hearing music in high fidelity, you’ll probably be better off with a set of wired headphones; if you need everything to sound great but prefer the convenience of wireless connections, go for a pair of Bluetooth headphones.

Dale: There are so many types of amplifiers (and DAC’s with amplifiers) that there is no shortcut for studying all of the options, unless you settle for the most generic approach. Important things to consider are power – if you don’t have enough power for your headphone and the dynamics in the music, clipping will result. Sometimes the clipping is “soft” and not readily noticed, but eventually you would discover that much of the detail goes missing or gets veiled with limited dynamics. Another consideration is whether to use a DAC, which may be a separate DAC or built into the same enclosure as the amp. Most DACs will improve the sound over the DACs that are built into computers, but when a DAC is available to replace the DAC built into most cellphones and low to mid-priced music players, you can usually expect a much greater improvement.
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.
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]