never the sort of pants-flapping, sock-it-to-your-gut experience you literally feel from massive speakers or subwoofers. Those systems' bass is as much felt by your body as heard by your ears. Earbuds are tiny and portable, but, except for a couple of high-end models, they can't compete with full-size, over-the-ear headphones for deep bass response or visceral dynamic range. As with speakers, headphones need at least 10 hours of vigorous use before they sound their best.
Sealed or open?
Sealed headphones (the noise-isolating, in-ear models or the full-size ear-cup designs) acoustically isolate your ears from your environment. Of course, the degree of isolation varies from one pair of headphones to another, and the seal limits the leakage of the headphone's sound out to the room. Sealed models are ideal for private listening, where you don't want the sound to be heard by other people. Open headphones, such as foam ear-pad models and many sports designs, are acoustically transparent and allow outside sound to be heard by the headphone wearer, and a good deal of the headphone's sound will be audible to anyone near the listener.
Sealed headphones block outside noise.
Open-backed headphones allow external noise to reach your ears.
Generally speaking, such headphones produce better, more "open" and speakerlike sound than sealed designs. Precisely because they don't block out everything from the outside world, open-backed headphones are recommended for outdoor activities, such as jogging, that require awareness of your environment.
Comfort and weight
Assessing sound quality is always a subjective exercise, but the only way to judge comfort is to put on a set of 'phones and listen for at least 10 minutes. Do the ear pads exert too much pressure on your ears? Headphones that enclose or cover your ears can get uncomfortably hot, but you'll have to wear them for a while to find out. Some of the bigger sealed models with cushy leatherette pads are the worst offenders. Pro-style headphones are comparatively bulky and can feel uncomfortably heavy after hours of use. Lighter headband-style headphones are almost always more comfortable than heavier ones. And even if they're not, they're less of a hassle to carry around.
Durability
There's no reason a headphone should be treated as disposable technology. Unlike almost everything else in the realm of consumer electronics, this year's headphones won't be obsolete six months or a year from now. In fact, there's no reason a good pair of headphones can't last for the better part of a decade. Be sure to assess the build quality of your prospective headphones. Some earbuds and portable headphones are relatively fragile, for instance. If the headphones fold up for easy storage, are the hinges robust, or will they fall apart in a month or two? And consider that the ear pads and earbuds will get extensive wear and tear over the life of the headphones; while some models incorporate replaceable ear pads or ear tips, most do not.
Portability
Earbuds and lithe portables travel well, but those styles and ergonomics aren't for everyone. Despite their relative bulk, many airline travelers prefer large, full-size headphones that fully cover the ears. But some larger headphones travel more easily than others. Frequent flyers will want to look for collapsible headbands and folding ear cups when seeking out larger headphone models. Similarly, many headphones include customized carrying cases, which travel better than, say, wrapping your headphone cables around your iPod.
Cable dressing and length
Most stereo headphones have just one cable, usually attached to the left earpiece. Some models, and all earbuds, use a Y-cable that connects to both earpieces (double-sided). The actual cable plug, meanwhile, is usually one of two designs: a straight I-plug or an angled L-plug; the latter may be useful if your portable player has a side- or bottom-mounted headphone jack.
Single-sided headphone cables cut wire clutter in half.
Double-sided headphone cables can be tangle-prone.
Preferences for the length of headphone cables vary for portable users, especially depending on where you prefer to wear your device: a backpack or a pants pocket necessitates a longer cable, while you'll opt for a short one when wearing a player on a neck lavalier or an armband. But a cable length at either extreme need not be a fatal flaw: extension cables can lengthen those that are too short, and cable wraps can tighten up ones that are too long.
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 headphones.
Total harmonic distortion
True, headphones with lower actual total harmonic distortion (THD) will sound better than 'phones with higher THD. But the quoted THD numbers, "less than 1 percent", aren't helpful in predicting sound quality. Listen to recordings of simply recorded acoustic guitar to assess the distortion of one set of headphones vs. another. Some will sound appreciably cleaner than others.
Impedance
Generally speaking, the lower the headphones' electrical impedance (aka resistance), the easier it is to get higher volume. But here again, the low impedance is no guarantee of high volume capability; other factors can still limit loudness potential. Since many MP3 players have feeble power output, the iPod is a notable exception, smart shoppers should check the loudness before purchasing any pair of headphones. To be sure, listen with your player.
