For older models of telephones, the headset microphone impedance is different from that of the original handset, requiring a telephone amplifier for the telephone headset. A telephone amplifier provides basic pin-alignment similar to a telephone headset adaptor, but it also offers sound amplification for the microphone as well as the loudspeakers. Most models of telephone amplifiers offer volume control for loudspeaker as well as microphone, mute function and switching between headset and handset. Telephone amplifiers are powered by batteries or AC adaptors.

Released in 2017, the Bose QuietComfort 35 (Series I) are essentially the exact same headphones as the Series II. They have the same design, feel, sound quality and noise-canceling skills. The difference is that the Series I don’t have Google Assistant built-in and a dedicated button on the left ear cup to activate it. If you don’t care about talking to a virtual assistant while wearing your headphones, which allows you to play/pause music or skip tracks via a verbal command, then Series I or Series II shouldn’t matter to you. The catch is that the Series I is more difficult to find online and they aren’t usually that much cheaper than the Series II.
While noise-canceling headphones are what it’s best known for, Bose makes plenty of other high-quality headphones and earbuds for people who don’t want or need noise cancellation, which degrades audio quality and costs a premium. From true wireless AirPod competitors to old-school wired earbuds, to just cheaper wireless over-ear cans, Bose makes a headphone for every style and, more importantly, for every budget.
The fit isn’t always an easy thing to be sure of when you can’t try before buying, since some ear pads will not have a satisfactory fit to some ears. Power requirements aren’t a simple matter of looking at the impedance, since efficiency or sensitivity doesn’t always track directly with impedance. Another issue indirectly related to power requirements are whether the headphone has the option for ‘balanced’ use or some other connection that isn’t a 3.5 mm or 6.35 mm jack and plug.
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.
We’re totally convinced the Sony WH-1000xM3 will be the best pick for most people, but if you’re looking for some alternatives, we have you covered there, too. We identified seven other models that are more than worthy of your consideration, each with their own specific strengths, whether it’s for use during a workout — or merely to keep you from giving your credit card too much of a workout.
Wireless and truly wireless: These connect to your devices using Bluetooth, so you’re never physically tethered to your smartphone, tablet, or computer. Wireless headphones don’t use a wire to connect to an audio source, but they do use a wire to connect the two earpieces together. In contrast, “truly” wireless headphones come as two separate earpieces that don’t need wires to connect to anything. Wireless headphones are incredibly affordable; truly wireless headphones can cost anywhere from $100 to $400.
Again, back on the automobile analogy. If you’re driving in downtown Chicago after winter time, the road is full of potholes. It would be nice to be riding in a nice SUV, rather than typical sports car with a fully stiff suspension. It doesn’t matter if your sports car happen to cost three times the cost of the SUV, it’s just the wrong car for the road. Likewise headphones. A $1,000 headphone can sound very awful on the wrong music. Don’t believe me? Try listening to Linkin Park with the $1,800 Sennheiser HD800. You will wonder where that $1,800 went.
These headphones pack about 16 hours of battery life, which ought to be enough for a whole day or more, but if not, there’s always the option of using an analog cable instead. An external switch lets you turn the noise cancellation on and off. Make no mistake, these might be aimed at kids, but the quality of construction, selection of materials, and color choices give them an appearance that will still appeal to your young charges long after they’ve outgrown their Disney phase (some of us still haven’t).

I will get to these today. Just imagine the sound you hear is a line stretching left to right, with bass at the left and treble to the right. Now the line is tilted toward the right so the bass is higher (stronger) and the treble lower (weaker). That’s an example of getting darker. It’s not a perfect analogy, since any complex combination of sounds or balance is possible, but in general when something sounds darker you’ll have less influence of the treble.
The SoundSport Wireless are wireless sport earbuds that are very similar to the SoundSport Free. Instead of being true wireless earbuds, however, the two SoundSport Wireless earbuds are tethered together by cable. Aside from that, the two wireless earbuds have similar audio performance and use the same Bose Connect app. The SoundSport Wireless will last longer on a single charge (as opposed to the SoundSport Free which recharge every time they go back in their case).

I have heard only the 8.35D, which are slightly dark (tilted toward the low end a little bit). But the 8.35D is very smooth and linear overall, excellent for many genres if not all. With the SRH840 you should expect a big hump in the upper bass – not ideal for monitoring. The KRK 8400 seems like the most accurate of all which is ideal for monitoring, but that’s based on a bunch of reviews, and not all of them agree 100 percent.
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.
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 Bose QuietComfort 35 II is arguably still the most comfortable pair of noise-canceling headphones you can buy. Released in the summer of 2018, you can think of the QuietComfort 35 II as simplified, less sophisticated and more affordable version of the new Headphones 700. The lack the transparency mode, superior call quality, USB-C charging port and on-ear gesture controls, but they still boast really impressive noise-canceling skills. The also have the tradional foldable design — it folds more compactly — that many travelers really like.
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.
We still wish you could control volume using the same touch gestures that control playback, but then again, you can always ask Alexa to adjust the volume instead. Battery life at 5 hours per charge is about average these days, as is the 20 hours of total playtime enabled by the charging case. Both are minor drawbacks to what is by far the best value in the true wireless market today.
Released in 2015, the SoundLink Around-Ear II are Bose’s wireless over-ear headphones that don’t have active noise cancellation. They’re lighter and slightly more travel-friendly than a lot of the company’s other offerings, and they could sound quality at the forefront. At the time, the big selling point for the SoundLink Around-Ear II was their sound quality — Bose claimed that they sounded as good as wired headphones, which admittedly doesn’t hold up in 2019 (streaming and Bluetooth have gotten too good).
In the professional audio sector, headphones are used in live situations by disc jockeys with a DJ mixer, and sound engineers for monitoring signal sources. In radio studios, DJs use a pair of headphones when talking to the microphone while the speakers are turned off to eliminate acoustic feedback while monitoring their own voice. In studio recordings, musicians and singers use headphones to play or sing along to a backing track or band. In military applications, audio signals of many varieties are monitored using headphones.
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