One of the hardest things about shopping around for technology is facing down the sheer number of options out there. With the advent of smartphones, the peripherals market became suddenly flooded with competition as manufacturers tried to stake a name for themselves and grab a piece of high consumer demand.

The headphone industry has its roots in the '60s, when the boom of solid-state transistors created as big a techno-cultural shift as today's--however, vintage equipment generally was intended for home listening and tended to favor a philosophy in sound reproduction we reserve for "audiophiles" today. The modern headphone landscape has created new niches and a more discerning consumer base, and a lot of confusion out there about what exactly makes a good pair of headphones. So let's start with the basics:


Design

How much headphone do I want?

Any headphone you buy will generally fall into one of three design categories: Over-Ear, In-Ear, and On-Ear. These distinctions are fairly obvious, but let's get into what makes their listening experiences different and why.

Over-Ear:

The traditional headphone, this design features two large earcups that completely cover the listener's ears (also called a Circumaural design.) Over-Ear headphones benefit from increased sound isolation from their surroundings due to creating a seal between the speakers (called Drivers) and the ear. Most audiophile-type headphones are Over-Ear designs as they allow the most control over external variables and provide a sturdy platform for bigger drivers or stronger magnets. One of the downsides of Over-Ear headphones is size and weight, as many can be inconveniently bulky or heavy or uncomfortable to wear one long periods of time. For listeners who are physically active while listening, the size can be an issue to restrict movement-- and the passive sound isolation might not be appropriate for office use.

In-Ear:

In-Ear headphones, including Earbuds and In-Ear Monitors (IEM) are units that are inserted either in the outer ear or into the ear canal itself. These headphones are often bundled with portable devices due to their compact and portable design, and are often the most inexpensive headphone option--though quality In-Ear Monitors can rival high-end Circumaural sound. Earbuds are the most common, and sit in the outer ear. Unfortunately due to poor sound isolation, these earphones are often used at dangerously high volume levels to compensate. In-Ear Monitors protrude into the ear canal, and create a seal much like Over-Ear headphones, allowing for higher quality sound reproduction and comfort during use. In-Ear headphones are great for active users as well as casual listeners, and mostly due to cost are the most common design out there today.

On-Ear:

Though they acquired the somewhat derogatory sobriquet "Walkman Headphones," On-Ear or "Supra-Aural" headphones are usually smaller and lighter than their Over-Ear equivalents and can provide excellent performance. Instead of covering the ear, they sit flush against it with a soft foam pad. Many favor On-Ear headphones due to their light weight and comfort compared to earbuds, but certain designs can be uncomfortable over long periods of time. Many On-Ear headphones utilize an Open Design, which brings us to...


Drivers, Transducers, Impedance, Amplifiers and Open & Closed Headphones:

How is my sound going to be reproduced?

Another factor to be aware of in Over-Ear and On-Ear headphones is whether they employ an Open or Closed design. The majority of headphones are Closed-back, meaning that an isolating chamber is created inside the ear cup, making for better sound isolation and minimal noise-leak as well as improved bass performance. Open-back headphones allow air and sound to leak in and out of the headphones, making sound reproduction more natural and acoustic and emulating space--but might not be suitable for loud listening environments (or very quiet ones, where noise-leak may be inappropriate.) Closed headphones typically have a narrower Soundstage (the perception of acoustic space) than Open designs.

Another common distinction between headphones is their method of reproducing sound. Drivers or alternately Transducers are a number of devices that convert electrical input into sound output. The most common transducer is the Moving Coil or Dynamic driver. This approach is most similar to loudspeakers and PA systems, and relies on alternating a magnetic field created by a powerful ferrite or Neodymium magnet with a flexible diaphragm and a Voice Coil, which reacts to the field by moving air, producing sound. Dynamic drivers are a reliable and well-understood technology, but can (especially in higher-end models) become heavy and bulky due to their moving parts and larger magnets.

Electrostatic transducers are much less common, but were for a time found in only the highest end headphones and speakers. This transducers uses an incredibly thin electrically charged diaphragm suspended between two perforated electrodes that create a magnetic field, pushing air through the perforations and creating sound. Electrostatic designs can produce incredibly accurate sound and frequencies much higher than Dynamic drivers, and are very mechanically stable due to the lack of moving parts. However, Electrostatic headphones often necessitate an external power source and amplifier in order to function, limiting them to (primarily) indoor usage. Similarly, Orthodynamic (or Planar magnetic) transducers also allow for a lightweight and incredibly accurate sound--but typically do not have the same power demands as Electrostatic drivers.

Speaking of amps, all headphones possess a quantity known as Impedence, meaning the amount of power necessary to drive their transducers. Impedance is measured in Ohms (symbolized Ω) and headphones typically exist in a range between 16-600Ω. Low-Impedance (under 32Ω) headphones do not require an external power source or amplifier, and headphones up to 62Ω can typically be driven by a computer or smartphone. High-Impedance models (typically around 250Ω or more) usually require the usage of an external headphone amplifier to produce the power needed to really enable their superior performance. You might notice that using a High-Impedance model without an amp results in a flatter, muddier, or quieter sound. Similarly, even Low-Impedance models can be improved with the addition of an amp.

Amplifiers increase the power of a signal, and allow listeners to control more precisely the volume and power going into their headphones. Headphone amps range from tiny portable units that can be paired with a smartphone to large tube amps meant for desktop use. Typically, audiophile headphones are high-end models are intended to be used in conjunction with an amplifier.


Sound

Dynamic Range, Sound Color, and Audio Branding: How do I want to listen?

Take a moment to browse through the forums over at audiophile capital Head-Fi and you might think "what are these guys talking about all day?" In truth, while everyone's hearing and audio preferences are different, there are a few mostly-objective ways we can describe sound that can help us make great consumer choices and actively compare qualities that we typically think of as ephemeral and unquantifiable.

Headphone manufacturers can throw a lot of technical specifications at you, and while these quantities can tell you some things about sound, the best way to judge headphone quality is to listen to and compare headphones in person. However, this info can point you in the right direction--particularly the Sound Pressure Level, which will give you an idea of how loudly your headphones can output sound. A higher pressure level is equivalent to a higher potential volume. One other important specification is the Total Harmonic Distortion which measures the likelihood that sound will become distorted at high volumes, so you will want to aim for as low a THD value as possible. Typically THD is below 1%, but audiophile models can near .1% or lower.

In a more general sense, you might hear people talking about sound "color" or tuning. Every major manufacturer, even those producing very accurate monitor headphones (headphones that attempt to reproduce sound without adding adjustments,) imbues a unique quality in their sound reproduction known as color. Colored sound is the amalgamation of adjustments and tweaks to audio as it leaves the source and is reproduced through your headphones, and can range from minute (Studio monitors) to substantial (DJ headphones and Beats.) Pay attention to marketing, a pair of headphones with prominent DJ branding likely signifies a Bass-heavy sound profile, whereas an appeal to strictly numeric and technical data is more likely to lean toward monitor or Flat sound. These are just guidelines and above all else, trust your ears. There is nothing intrinsically better or worse about colored sound or "perfect" reproduction.


In Conclusion

At the end of the day, any pair of headphones can do the job--but whether you take sound seriously and are ready to make an investment, or are looking for something cheap and easy to throw in your bookbag, it's always good to know how to compare options to get the best bang for your buck. I highly recommend trying out a few different models at your local store, and be sure to ask questions of the staff! They will be able to help you find a great fit, both physically and sonically. And you, with your new knowledge, will be able to ask the right questions. In addition, there are many great resources and reviews out there to get real impressions of models you are interested in, so be sure to do your research. Happy listening and good luck!



This post was written by John Morabito from Audio46.com as part of Audiophile Week, a partnership and celebration of audiophile culture from Audio46 and The 405. John Morabito is a Tech lover and audiophile headphones enthusiast who is known for his reviews of headphones on the Audio46 Youtube channel and blog. Audio 46 is one of the USA's leading headphone specialty stores serving headphone lovers with outstanding content, customer service and expertise.

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