What will you be listening to?

After you've chosen a design that meets your needs and that's comfortable for you, you should take a look at some of the specs listed for each model you're considering to find a pair that fits your listening habits. Different drivers and materials reproduce sound differently, so you should acquaint yourself with a few terms so that you know what to look for.

Drivers and armatures: What's inside?
If sound quality is important to you, then be sure to choose a well-built pair of headphones, no matter what design you choose. Pay attention to the type of driver that's producing the sound, since it'll help determine the sound quality. Most headphones use "dynamic" drivers, which work much like any full-sized speaker. You can count on them to deliver a full range of sound with plenty of detail and clarity.

Balanced armatures are much more efficient than dynamic drivers and can be built smaller, so they're mostly used in in-ear headphones. However, they're generally limited when it comes to reproducing extremely low or high frequencies, and require a good seal in your ear to deliver their full audio range.

Frequency response: How low — and high — can they go?
The frequency response is the range of sound that the headphones can produce, measured in Hertz (Hz). When you're looking at the numbers, keep in mind that the human hear can generally only perceive sounds from 20 to 20,000 Hz. Most headphones can easily cover this range. Some may claim to go beyond it, but the tiny drivers and armatures in headphones traditionally have difficulties reproducing sounds lower than 20 Hz. Still, the wider the range the better, since the bass will be lower and the treble higher, giving you better overall sonic performance.

If getting accurate, dynamic sound is your main concern, then go for some high-quality home headphones that can handle a broad frequency range. Fans of jazz and classical music should pay extra attention to headphones that deliver more detail in the midrange and highs. For rap and hiphop, go with 'phones that deliver more lows. (Generally, if you want more bass, then you'll want to go with larger home headphones, since their size allows for better low frequency response.)

Impedance: How much power do they draw?
One issue that's especially important for portable headphones is impedance. The higher the impedance, the more electrical energy is required to drive the headphones' tiny speakers. Because of the limited power available from a portable player, headphones for portable use should have a maximum impedance of 64 ohms — the lower the impedance, the more efficient the 'phones, and the more battery life you'll get out of your player.

Some helpful accessories for the Sennheiser CX 400s pictured above (clockwise from top left): clothing clip, extension cord with stereo mini plug, carrying pouch, interchangeable ear gels, cord wrap.

Other important details to consider

When you're shopping for a pair of headphones, make sure the cord terminates in a plug size that's compatible with the component or portable you'll be listening to. Most headphone cords end in a stereo mini plug; if your source has only a full-sized output, you'll need an adapter. Some headphones come with one or more adapters, but if the 'phones you want to buy don't include one, an adapter is relatively inexpensive.

Some headphones include detachable parts, like ear cushions or cords, that you can replace if you need to. Pretty handy — if you mangle the cord in your vacuum cleaner, you won't need to buy a whole new set of headphones. But of course, an ounce of prevention is worth a pound of replacement gear: if your 'phones are going to be in rough surroundings, look for a model that comes with a carrying case.

Be careful of your hearing — please

High-volume listening is causing severe hearing loss in more and more individuals these days, with aural damage starting at a younger age. So what can you do to protect your ears? Start by listening at lower volume levels, and not relying on volume to mask loud external noise.

Also, consider that when you insert an earbud into your auditory canal, it has the effect of increasing the decibels considerably. This happens because less of the sound is dispersed and more of it reaches your eardrum. You may want to switch to on-the-ear or over-the-ear headphones for sustained listening, and only use your earbuds for limited portable listening. Headphones with noise-canceling technology can also help you keep the volume low without any loss in enjoyment, by reducing the outside sounds that might otherwise cause you to turn the volume way up.

For more tips on safe listening, learn about how your hearing works and what you can do to protect it.