Given how frequently iPods and other portable media players are used in noisy environments, headphones that reduce some degree of outside noise have become popular accessories. Although there are several approaches to such noise reduction, today I take a look at nine full-size,\n\tnoise-canceling\n\theadphones.\n\nNoise-canceling technology\n\nHeadphones designed to reduce the amount of external noise that makes its way to your ears use one (or both) of two approaches: passive and active noise reduction.\n\tPassive\n\tnoise reduction involves physically blocking noise from reaching your ears. Traditionally, this has been accomplished via larger headphones that completely surround your ears (a.k.a., circumaural designs), although over the past ten years or so, it has also found a popular solution in\n\tin-ear-canal headphones\n\t(a.k.a., \u201ccanalphones\u201d), which fit deep in your ear canals like earplugs.\n\n\nActive\n\tnoise reduction, on the other hand, aims to reduce the level of external noise via technology. Also known as\n\tnoise-canceling\n\t(NC) headphones, these designs often include elements of passive noise reduction\u2014for example, large, circumaural earpieces\u2014but also include special noise-canceling circuitry: One or more microphones built into the headphones sample external noise; an inverse audio signal is immediately fed back into the headphones, \u201ccanceling out\u201d\u2014in theory\u2014that noise.\n\n\nNoise-canceling technology is not without its limitations. For one thing, because active noise cancelation is reactive, there\u2019s the slightest delay between when a sound is detected and when that sound\u2019s inverse signal is sent through your headphones; the effect of this delay is that NC headphones tend to be much more effective at blocking constant audio\u2014a jet\u2019s engines, the rumble of train tracks, the buzz of traffic or a crowd, the hum of a room full of computers\u2014than they are at counteracting discrete sounds such as a person talking, a baby crying, a dog barking, or the random noises in a busy office or factory. In addition, most NC headphones block only a limited range of frequencies; high frequencies, for example, aren\u2019t \u201ccanceled\u201d nearly as well as others. Finally, NC circuitry can introduce an audible hiss or hum, along with a sense of physical pressure on your eardrums, during listening.\n\n\nThere are also drawbacks associated with sound quality. Because a good chunk of the cost of NC headphones is spent on the noise-canceling technology, the audio components are generally not as good as they would be on similarly-priced standard headphones. And because you\u2019re hearing your music along with an artificial noise-canceling signal, there is some degradation of sound quality when NC circuitry is present.\n\n\nBecause of these limitations, many people opt instead for a good set of in-ear-headphones, which have the potential for better noise isolation as well as superior audio quality. However, NC models have a few advantages of their own. The biggest is that NC headphones don\u2019t require you to be completely isolated from the outside world\u2014you can still (mostly) hear people talking around you, and you can hear non-constant noises such as a phone ringing or a knock on the door. And unlike in-ear-canal headphones, which can be a hassle to insert and remove, NC headphones are as easy to put on and take off as any standard headphones. Finally, whereas a good number people find in-ear-canal headphones to be uncomfortable, most NC headphones are relatively luxurious, with plush earpads and thick headbands.\n\nNC headphones compared\n\nWith this background in mind, I\u2019ve taken a look at a nine noise-canceling headphones, ranging in price from $150 to $450. All require battery power for their noise-cancelation circuitry to function, and all offer some degree of passive noise isolation via thick earpads that sit on or around your ears. All are designed for travel, with earpieces that rotate flat for storage; a standard, 1\/8-inch (3.5mm) headphone plug; a standard accessory package of a hardshell carrying case and and an airline (two-prong) audio adapter; and a removable headphone cable for those times when you don\u2019t want to listen to audio but still want to take advantage of the headset\u2019s noise-canceling and -isolation features. Finally, all but two allow use as standard headphones when the NC circuitry is disabled (or your battery dies).\n\n\n(Note that our ratings are for noise-canceling headphones\n\tas noise-canceling headphones\n\t; they\u2019re not directly comparable to standard or in-ear-canal headphones, which generally offer better sound quality at a given price.)\n\n\n\n\tNoise-canceling headphones compared\n\t\n\t\n\t\n\t\n\tPrice (MSRP)\n\tComfort\n\tPassive Isolation\n\tNC Effectiveness\n\tLack of Hiss\n\tLack of Pressure\n\tSound: NC On\n\tSound: NC Off\n\tPlaylist Rating\n\t\n\t\n\tAble Planet Clear Harmony\n\t$350\n\tGood\n\tFair\n\tFair\n\tGood\n\tGood\n\tFair\n\tFair\n\t\n\t\n\t\n\t\n\t\n\tAudio-Technica ATH-ANC7\n\t$220\n\tEx.\n\tEx.\n\tEx.\n\tEx.\n\tEx.\n\tEx.\n\tFair\n\t\n\t\n\t\n\t\n\t\n\tBose Quiet Comfort 2\n\t$299\n\tEx.\n\tEx.\n\tEx.\n\tEx.\n\tGood\n\tGood\n\tNA\n\t\n\t\n\t\n\t\n\t\n\tBose Quiet Comfort 3\n\t$349\n\tEx.\n\tGood\n\tEx.\n\tGood\n\tGood\n\tEx.\n\tNA\n\t\n\t\n\t\n\t\n\t\n\tJabra C820s\n\t$199\n\tGood\n\tGood\n\tGood\n\tGood\n\tGood\n\tGood\n\tFair\n\t\n\t\n\t\n\t\n\t\n\tLogitech NCH\n\t$150\n\tEx.\n\tFair\n\tGood\n\tEx.\n\tEx.\n\tFair\n\tPoor\n\t\n\t\n\t\n\t\n\t\n\tOutside The Box Solitude\n\t$250\n\tFair\n\tFair\n\tPoor\n\tPoor\n\tEx.\n\tFair\n\tFair\n\t\n\t\n\t\n\t\n\t\n\tPanasonic RP-HC500\n\t$200\n\tGood\n\tEx.\n\tEx.\n\tGood\n\tEx.\n\tEx.\n\tFair\n\t\n\t\n\t\n\t\n\t\n\tSennheiser PXC 450\n\t$450\n\tGood\n\tGood\n\tGood\n\tEx.\n\tEx.\n\tGood\n\tGood\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\tNOTES: Category ratings based on Excellent, Good, Fair, or Poor; Playlist Rating is out of 5.\n\tSound: NC On\n\tand\n\tOff\n\trefers to sound quality with noise-canceling circuitry enabled and disabled, respectively.\n\n\n\nProduct summaries\n\n\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\n\n\n\tAble Planet Clear Harmony\n\t\n\t($350): The Clear Harmony\u2019s around-the-ear cups are comfortable, although the top of the headband pressed down on my head a bit, and the headband\u2019s resizing mechanism collapsed too easily. The earpiece cups were also a bit smaller than some of the other around-the-ear versions; I have average-to-small ears, and the Clear Harmony\u2019s cups didn\u2019t completely surround my ears, which reduced the amount of passive noise reduction. (This also made it difficult to test the effectiveness of the noise-canceling circuitry.) Overall sound quality isn\u2019t great; while the Clear Harmony has good bass response, a lack of treble makes the audio sound somewhat muffled. This effect is somewhat worse with the NC circuitry disabled.\n\n\nThe Clear Harmony weighs approximately 9 ounces. Besides the standard accessories, it includes a 1\/4-inch headphone-jack adapter, and the 5-foot cable features an inline volume control. It runs off two AAA batteries, and its carrying case provides a slot for storing your iPod.\n\n\n\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\n\n\n\tAudio-Technica ATH-ANC7\n\t\n\t($220): The ATH-ANC7 is very comfortable, although, like the Able Planet model, its earcups are a bit smaller than some of the other models tested; those with large ears may not be able to get the cups to completely surround their ears. Sound quality (with the NC circuitry enabled) is excellent for NC headphones; the ATH-ANC7 is on par with the Bose QC3, although with a bit more treble detail and less midrange and bass. On the other hand, disabling the NC circuitry results in a dramatic change in sound quality, as audio is quite muffled and distant.\n\n\nThe ATH-ANC7 weighs approximately 7 ounces and includes the standard accessories as well as a 1\/4-inch headphone-jack adapter. It uses a single AAA battery.\n\n\n\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\n\n\n\tBose QuietComfort 2\n\t\n\t($299): Back in February 2005, we\n\treviewed\n\tBose\u2019s QuietComfort 2 (QC2), finding the headset to be, as its name implies, comfortable and quiet, with good sound as NC headphones go. The biggest drawback of the QC2 was its price, which at $299 was (and remains) $50 to $150 more than a number of quality alternatives. One feature not mentioned in our full review: the QC2\u2019s cable includes a integrated Hi\/Lo switch, useful when connecting to ear-splitting airline headphone jacks. Unfortunately, the QC2 can\u2019t be used as regular headphones if you turn off the NC circuitry or if your battery dies.\n\n\nThe QC2 weighs approximately 6.5 ounces and also includes a 1\/4-inch headphone-jack adapter, a 5.5-foot main cable, a 5-foot extension cable\u2014allowing you to get over ten feet from your audio source\u2014and a shoulder strap for the case. It requires a single AAA battery.\n\n\n\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\n\n\n\tBose QuietComfort 3\n\t\n\t($349): The QuietComfort 3 (QC3) is the \u201csuccessor\u201d to the QC2, but Bose has kept the QC2 as a current model. The QC3 is $50 more expensive than its predecessor but adds a rechargeable battery and an external battery charger, as well as a new, smaller design\u2014compared to the QC2, the QC3 are a good deal smaller and over an ounce lighter (5.6 versus 6.9 ounces). This smaller size means the QC3 takes an on-the-ear approach, so it doesn\u2019t physically block as much external noise as the QC2; on the other hand, surprisingly, the unique on-ear pads block more sound than some of the other around-the-ear models tested here. The new, lighter design, which uses a neoprene-and-leather pad on the headband and super-soft leather earpads, results in one of the most comfortable headphones I\u2019ve worn. The overall sound quality of the QC3 is actually better than that of the QC2, with improved midrange performance, although bass is accentuated a bit much for my tastes and there is a slight sense of pressure on your eardrums from the NC circuitry. Like the QC2, the QC3 can\u2019t be used as regular headphones if you turn off the NC circuitry or if your battery dies.\n\n\nThe QC3\u2019s rechargeable, lithium-ion battery fits snugly into a slot at the top of the right earpiece. The battery offers approximately 20 hours of use per charge, and can be charged using the included AC charger (which fits in the QC3\u2019s carrying case). Although convenient and environmentally responsible, a rechargeable battery means you can\u2019t swap in a fresh pair of AAA batteries mid-flight. (You can purchase an\n\tadditional battery\n\tfor $50 from Bose; also available is a $50 international battery charger. Bose also offers is a $40 Cell Connect kit that lets you connect the QC3 to your mobile phone. This accessory includes an inline microphone for making phone calls on your phone without removing the headphones; you can switch between music and phone calls with a button on the microphone housing.)\n\n\nBose includes a 53-inch standard cable and a 5-foot extension cable, a 1\/4-inch headphone-jack adapter, and a shoulder strap for the case. On the other hand, in the \u201cwhat-were-they-thinking\u201d department, the jack on the QC3, into which you plug the headphone cable, is oriented such that when you rotate the earpieces for flat storage, the plug is in the way; you must remove the cable first.\n\n\n\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\n\n\n\tJabra C820s\n\t\n\t($199): One of the more affordable models tested, the C820s offers good comfort, good passive noise isolation, good NC effectiveness, and little hiss and pressure. It feels a bit less \u201cluxurious\u201d than some of the other models here, but it isn\u2019t uncomfortable by any means. Sound quality is pretty good with NC circuitry enabled, including good bass response, but only fair without\u2014volume is quite a bit lower and the audio sounds muffled as soon as you turn off the NC feature.\n\n\nThe C820s weighs approximately 7 ounces and also includes a five-foot cable, a 1\/4-inch headphone-jack adapter, and a 2.5-mm microplug adapter for using the headphones with many mobile phones. It\u2019s powered by a single AAA battery, which Jabra says will offer up to 50 hours of use.\n\n\n\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\n\n\n\tLogitech Noise Canceling Headphones\n\t\n\t($150): The descriptively-named Noise Canceling Headphones (NCH) is the least expensive model I tested, at least at official prices. Although very comfortable, the NCH uses rectangular earcups, instead of the oval-shaped versions on most other models. Theses earcups easily fit larger ears, but don\u2019t physically block as much external noise as other models. Although the NC circuitry produces little or no hiss or pressure, there\u2019s also a distinct lack of treble detail to the NCH\u2019s audio output with noise-canceling enabled, and audio quality with NC circuitry turned off was among the worst of the bunch\u2014tinny and distant.\n\n\nThe NCH weighs 6.5 ounces and includes a 5-foot cable and the standard accessories. I liked the NCH\u2019s hard case, as it included a nylon carrying strap as well as neoprene pockets on the inside specifically designed to hold an extra battery, the airline adapter, and the removable cable. It uses a single AAA battery.\n\n\n\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\n\n\n\tOutside The Box Solitude\n\t\n\t($250): The Solitude looks and fits almost exactly the same as the Able Planet Clear Harmony, above; even the carrying case is identical. However, it does have two differences. First, the Solitude includes a volume-adjustment dial on the bottom of the left earpiece instead of on the connection cable. Second, the Solitude\u2019s earpads are shallower than those on the Clear Harmony; this lets the earpieces themselves press against your ears, which gets uncomfortable over long listening sessions. The Solitude\u2019s audio quality suffers from similar problems as that of the Clear Harmony: good bass response but a lack of treble that makes the audio sound muffled. However, the Solitude wasn\u2019t quite as bad in this department.\n\n\nThe Solitude weighs almost 9 ounces and includes a 5-foot cable and the standard accessories. It requires two AAA batteries, and its carrying case provides a slot for storing your iPod.\n\n\n\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\n\n\n\tPanasonic RP-HC500\n\t\n\t($200): The RP-HC500 is very comfortable, with a fit similar to that of the Audio-Technica model but with larger earpads; however, one drawback to the Panasonic headset is that the headband doesn\u2019t extend as much as the other models here, making it a tighter fit for those with larger heads. Sound quality is quite good, falling just behind the Audio-Technica ATH-ANC7, which has better midrange and slightly better treble. Like most of the headphones here, audio quality degrades considerably\u2014sounding muffled and distant\u2014when you turn the NC circuitry off.\n\n\nThe RP-HC500 weighs 6 ounces and includes a 5-foot cable, the standard accessory package, as well as a 1\/4-inch headphone-jack adapter. It gets power from a single AAA battery, which the company estimates will provide 40 hours of use.\n\n\n\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\n\n\n\n\tSennheiser PXC 450\n\t\n\t($450): The PXC 450 is the most expensive model I tested, $100 more than even the Quiet Comfort 3. It\u2019s also the largest and heaviest NC headset of the bunch\u2014again, by a considerable margin. This is good for those with large ears or heads, as the PXC 450\u2019s ear cups are cavernous compared to the other models and the headband can extend to a generous length. Overall, the PXC 450 is comfortable, with plush, replaceable earpads and a soft headband. However, it doesn\u2019t block as much external noise as the best models here\u2014both because the earpads don\u2019t seal against your head as well and because the NC circuitry isn\u2019t quite as effective. Sound quality with the NC circuitry enabled is good, especially in the treble; these are good headphones for listening to classical and jazz. However, in noisy environments, the PXC 450\u2019s audio can sound inferior to that of the Audio-Technica and Bose models, simply because those headphones are more effective at blocking external noise.\n\n\nThe PXC 450 does provide some unique features for its higher price. For starters, Sennheiser designed the PXC 450 to be both a good noise-canceling headset\n\tand\n\ta quality set of headphones. If you turn the NC circuitry off and then flip a switch on the headset to \u201cbypass,\u201d you can use the PXC 450 as normal headphones, even if the battery is dead (or missing). And, indeed, unlike the other headphones here, audio quality isn\u2019t dramatically compromised when listening without the NC circuitry enabled; in fact, it\u2019s actually better\u2014this is a set of headphones you could use for both home and travel.\n\n\nThe other interesting feature is called TalkThrough. When the NC circuitry is enabled, a large TalkThrough button on the right earpiece allows some external audio\u2014primarily foreground sounds, such as the person talking next to you\u2014through, while background noise is still filtered out. This is a useful feature while on a flight when you want to hear the flight attendant without having to take off the headphones. And Up and Down buttons on the right earpiece let you adjust volume (when the NC circuitry is enabled) without reaching for your audio source.\n\n\nThe PXC 450 weighs 11 ounces and includes a 5-foot cable, the standard accessory package, and a 1\/4-inch headphone-jack adapter. (The PXC 450\u2019s thick cable is removable, but it doesn\u2019t disconnect easily.) The headset requires a single AAA battery; the case includes elastic holders for carrying extra batteries, as well as a nylon carrying handle.\n\nThe Lowdown\n\nWhich of these models should you choose? If cost is no object, Bose\u2019s Quiet Comfort 3 is luxuriously comfortable, blocks an impressive amount of external noise, and sounds very good for a noise-canceling headset. But when you throw price into the mix with comfort, noise reduction, and sound quality, my pick is Audio-Technica\u2019s $220 ATH-ANC7, followed closely behind by Panasonic\u2019s $200 RP-HC500, both of which compete favorably with the Bose models for a good deal less money. And unlike Bose\u2019s offerings, which are rarely discounted, a quick\n\tprice check\n\tshows that the Audio-Technica and Panasonic models are available for considerably less than MSRP\u2014under $125, in fact\u2014making them clear winners in terms of value.\n\n\nOn the other hand, if you want to regularly listen without NC circuitry enabled, most of these headphones fail miserably (if they let you listen this way at all). The only pair of NC headphones I tested that sounded good when used without noise-canceling was Sennheiser\u2019s $450 PXC-450. Although at that price, you could get one of the Audio-Technica or Panasonic headsets and still have enough left over to buy one of Sennheiser\u2019s better-sounding home headphones.