Noise can be so disturbing and boring at times that it makes listening to good music unbearable. It often times have made good music sound so bad that one can’t get the cool lyrics. If you are working in a noisy environment, ever boarded a noisy flight, you will agree with me that noise coming from the surrounding can be so bad that it becomes destructive to the ears. However, if you are a lover of good music, love using headphones to listen to music, but you are faced with the problem of noise, the solution is here. Active noise canceling headphones is the solution. These headsets can effectively put off all noise or sound coming from your environment, allowing you to listen to good music. Most of these noise canceling headphones is enhanced with wireless technology, which makes them more comfortable to use.
There are various models of these wireless Bluetooth noise canceling headphones on the market and getting one can be so confusing. For this reason, we have taken off time to put together this article (we titled the best noise canceling headphones reviews) containing some of the top wireless noise canceling headphone you can get in the market. Without any publicity, we sincerely believe these are the best wireless noise canceling headphone after taken into account and tested them for most of their features and performances such as how comfortable there are to wear, the active noise canceling abilities, Bluetooth connectivity, ease of use, sound quality, durability, battery life and type of battery used (rechargeable or not and whether the battery is replaceable), price, and the ability to be used in answering calls.
Bose QuierComfort 35
(Best Noise Cancelling Earphones)
The Bose QuierComfort 35 is one of our best noise canceling earphones we found while searching the market for the best noise canceling headphones reviews.
Bose QuierComfort 35 is regarded as a gold standard with respect to its active noise-canceling, and as it does a great job muffling sound, whether it be in a noisy open office environment, on a plane or the streets of New York. This headset is a wireless Bluetooth noise canceling headphones, which are extra-comfortable, sound excellent, fold-up design, and doubles as a headset for phone calls. However, it is heavier than some other headphones, and its battery isn’t user-replaceable.
If you are in the market looking for the best noise canceling headphones, then here is the Bose QuierComfort 35 for you. It is made up of an active noise canceling properties that's also wireless. It’s relatively lightweight, weighing in at 8.3 ounces or 236 grams. This one significant exterior design change Bose and has made it to widen the headband, which allows for a little more stable fit with sturdiness perhaps some added.
It is built with microphones inside and outside the ear-cups, which senses, measures and sends unwanted sounds to two proprietary digital electronic chips, one located in each ear-cup that respond with an equal and opposite signal.
This headphone is also equipped with a new digital equalizing system that balances the sound, making it pleasurable to play music at lower or higher volumes.
Battery life is 20 hours, which is quite good. However, it has an integrated rechargeable AAA removable battery configuration.
The juicy side about this headphone or why it is regarded as one of the best noise canceling earphones is that, it does work as a wired headphone if the battery runs low. You just can't use the noise canceling or Bluetooth, but at least it can provide you with some sound from it, and the tight seal of the ear cups provide for a fair amount of noise isolation.
While some airlines will restrict you from using Bluetooth headphones during some flight intervals, a cord (wire) is required to plug into your seat in-flight entertainment system. Thus, Bose QuierComfort 35 is a preferred choice when traveling.
This earphone (headphone) has the following properties:
· Comes in black or silver color
· It has top of the art active noise canceling
· 20 hours of battery life
· Sound is excellent
· Equipped with an active noise reduction and Bluetooth wireless connection
· Works in wired mode
· NFC pairing features for devices that support it
· Carrying case included
· Can also be used as a wired headphone (cord included)
· Price: $350
· Rechargeable battery
· Works as an advanced wireless Bluetooth headphone
· The headphone can still play your music on wired headphone mode if the battery dies.
(Wireless Bluetooth Noise Canceling Headphones)
With the exception of a few downsides, the SONY MDR-100X is rated among the top wireless noise-canceling headphone that's stacked with great features and sounds excellent.
The Sony Sony MDR-1000X is a great-sounding, comfortable wireless headphone with an effective noise-canceling that is at times said to beat the Bose's for muffling ambient noise. Its battery life is good and some nifty extra features geared toward frequent travelers.
The Sony MDR-1000X headphone has microphones on both the outside of the ear cups (to measure ambient noise), and the inside (to take account whether you wear glasses, and the shape of your head and ears).
This earphone is great as it allow you to choose alternate settings that may allow more ambient noise to get in or even filter out everything noisy, but allow voices so that you are able to hear announcements in airports and train stations while listening to music.
One other great feature of this Sony MDR-1000X is the ability to muffle your music and let the outside sound and voices in by simply holding your hand over the right ear cup, which houses the touch controls. Once you finish talking, you simply remove your hand and the music resumes playing at its previous volume and noise cancellation setting.
This earphone has a battery life of 20 hours and an included cord if you want to listen in wired mode. If the battery dies, you will still be able get sound out of it, but it sounds better as a powered headphone in wired mode. However, you don't need power to use it as a corded headphone.
This is Sony’s first headphone to be equipped with its Digital Sound Enhancement Engine (DSEE HXTM) built-in to be allow upscale of compressed music from whatever source to near hi-res audio sound, even in wireless mode."
Plantronics BackBeat Pro 2
(Best Wireless Noise Canceling Headphones)
The Plantronics BackBeat Pro 2 is also among the best wireless noise canceling headphones that costs as much as half price for other models from Bose, Sennheiser or Sony.
The Plantronics BackBeat Pro 2 sounds excellent for a Bluetooth headphone, offers great noise cancellation, comfortable to wear and has a longer battery life. It also adapted and functions very well as headphone for making cell phone calls, and an overall excellent value. However, noise canceling isn't as effective as Bose's, the headphone is still a little heavy, and its aesthetics make up or finishing may not appeal to everyone.
The best wireless noise canceling headphones from the Bose, Sony and others tends to cost much (at least $350) while the Plantronics’ BackBeat Pro2 cost just $250, half cheaper. Hence; it got a moderate price in the world of the best noise canceling headphones.
This is a comfortable headphone, and has sensors that allow you to easily pause and resume your music by simply taking off or putting on the headphones. It also allows you to answer your calls by simply putting them on your ears. Although its noise canceling property isn’t as effective as the Bose, it is great at muffling the ambient noise while eliminating all audible hiss.
The control buttons, such as the ring for adjusting volume levels, are located on the left ear-cup, together with a button that allow you to switch on to activate an open microphone mode and allows ambient noise into your headphone in order to hear your surroundings better.
Other features of this earphone that makes it to be ranked among the best wireless noise canceling headphones consist of:
- 15% lighter and 35% smaller than the previous generation model.
- It has smart sensors that are capable to automatically pause or resume your music as you remove or put on your headphones.
- New ear cups for better ear coverage and ergonomics, with a flexible ear cup mount.
- Allow connecting to up to two devices at the same time and can easily switch between devices.
- Ear cups that can be folded and protective sleeve for travel
- Built-in dual microphones to answer phone calls
- 24 hours battery life for continuous listening and can last up to 21 days on standby.
- 3.5mm cable so you can use this as a wired headphone if your battery runs out.
- Can hibernates for as long as 6 months if it's left on by mistake.
- 328-foot (100-meter) range if you pair it with a Class 1 Bluetooth device.
- Price: $200, £230 or AU$299
- Utilizes Bluetooth 4.0
- Special edition BackBeat Pro 2 SE is also available in the market with a hard travel case, in graphite gray and more premium finishes for $250, £250 or AU$349.
Sennheiser PXC 550 Wireless
(Top Wireless Noise Canceling Headphone)
While it doesn't quite look like the less-expensive Bose, the Sennheiser PXC 550 Wireless headphone is comfortable and feature packed and performs very well.
The Sennheiser PXC 550 Wireless is featuring in this article a top wireless noise canceling headphones for several reasons. It’s very comfortable, features impressive noise-cancellation technology, longer battery life, sounds very good and is a relatively lightweight over-ear wireless headphone. It delivers excellent performance as a headset and has touch controls.
However, it's more expensive than the Bose, lacks that little bit of a definition (Sennheiser's own Momentum II Wireless sounds better).
Sennheiser's is taking over the market with its new PXC 550 Wireless headphone, a "premium" over-ear Bluetooth headphone that also has active noise-cancelation.
Sennheiser PXC 550 Wireless sounds excellent (sound natural) and transparent when you add a lot of digital processing (active noise canceling plus Bluetooth). However, if sound quality is what you're looking for, the Sennheiser Momentum II Wireless is a better choice.
Sennheiser also allow its PXC 550's sound quality, to be customizable through the company's CapTune app for iOS and Android, 30 hours long battery life, touch controls, and strong headset performance for making phone calls.
Sennheiser PXC 550 Wireless however, steps in as the best noise canceling headphones Reviews because it comprises of the following features:
· Price: $399, £329, AU$630
· Fold-flat, lightweight design (8.0 ounces or 227 grams)
· Bluetooth 4.2
· NoiseGard adaptive noise cancelation monitors ambient noise levels to provide the exact level of suppression it needs.
· Battery life lasts up to 30 hours with noise cancelation turned on
· Four presets for adjusting sound and one customizable Director mode that can be tailored using Sennheiser's CapTune companion app,
· Ear cup mounted touch control sensor and voice prompt system
· Sensors that automatically pauses music when headphones are removed
· NFC technology to pair devices by simply allowing them to touch each other
· Speech clarity is great for both personal and business calls, ensured by a beam forming array with three microphones
· Travelers carry case with ease
Sennheiser Momentum 2.0 Bluetooth Headphone
(Best Wireless Noise Canceling Headphone)
The Sennheiser Momentum 2.0 Wireless headphone is an excellent and a well-designed Bluetooth headphone that also features as an active noise-cancelation, excellent sound over Bluetooth as well as, over a wired connection and has dual microphones for use in calls. However, it is more expensive than most other wireless Bluetooth noise canceling headphones such as the Beats Studio Wireless, and you won’t be able to turn noise-cancelation off when on Bluetooth mode.
Sennheiser has tweaked the designs of both its Momentum on-ear and over-ear models. Both the wireless and wired versions have a new folding design that makes the headphones more comfortable and gives it a slightly smaller footprint when they're in their included carrying case.
The Sennheiser Mumentum 2.0 (the wireless model) is made with a little bigger and softer ear cups to ensure they fit over your ears better and don't pinch anything.
More to its Bluetooth 4.0 capabilities, the Momentum 2.0 Wireless also features near-field communications tap-to-pair technology for compatible devices, active noise cancellation and supports the aptX codec when streaming over Bluetooth. Also, you are able to attach a cable and use the headphone as a wired headphone which enables the headphone not only to sound better but also louder.
Its buttons including the volume and playback controls, and the power on/off button, are all on the right ear cup which makes it easy enough to operate.
This model of Sennheiser also featured some built-in voice prompts (soothing female voice) which informs you when your headphones are paired with your Bluetooth-enabled device (such as iOS, Windows, and Android phones), the headphones are powered on or off, and/or alerts you when the battery is low.
Wireless range is great (about 33 feet or 10 meters) and also the wireless connection, though you will run into a bit of Bluetooth interferences now and then.
The Sony H.ear On Wireless NC
(Wireless Bluetooth Noise Canceling Headphone)
Priced to compete with Bose's QuietComfort 35, the comfortable H- ear On Wireless NC impressive sound and the Sony H- ear On Wireless NC is a comfortable, effective noise canceling premium wireless Bluetooth headphone that offers melodious sounds for a wireless headphone, performs well as a headset for making calls and that makes it a strong contender in the category. However, it’s somewhat more expensive and don't fold flat.
Many customers have been a little dissatisfied with Sony's wireless headphone offerings in the past, however the Sony H- ear On Wireless NC headphone is said to be the best Bluetooth headphone till date.
The Sony H- ear On Wireless NC headphone also known as the MDR-1ABN. Is very comfortable, light weight at 290 grams or 10.25 ounces (but a little heavier than the Bose QuietComfort 35) and isn't quite as comfortable as the Bose.
This headphone model comes in five different colors, so eye-catching and with a great finishing.
Its buttons, including its volume and track controls are all on the right ear cup which makes it easy to operate. You are able to turn the noise canceling on or off or plug in a cord and use it as a wired headphone if you so desired. It has an Automatic AI Noise Canceling feature which constantly analyses ambient sound and automatically selects the most effective noise canceling mode.
It has two built-in microphones, one outside and one inside the housing which make it a good headphone for making cell phone calls.
It also has a 20 hour battery life with noise canceling and Bluetooth on. However, this can last longer if you turn off the noise canceling and bring the volume down.
This Sony headphone arguably sounds natural for a Bluetooth headphone and it’s better than the Bose QC35. Well balanced, with good clarity sound and tight bass that isn't overpowering.
Plantronics BackBeat Pro
(Best Noise Cancelling Earphones)
The Plantronics BackBeat Pro features in our best noise canceling headphone reviews for many reasons. This best wireless Bluetooth noise canceling headphone is comfortable to wear, have excellent battery life, sound decent and come with a nice carrying pouch. However, it’s fairly heavy at 360 grams and the bass and treble may be a little too hyped for some people.
Plantronics top wireless noise canceling headphone is better known for its mono wireless headsets, but BackBeat Pro is a game changer. It's a cheap (at $250) over-the-ear wireless Bluetooth active noise-canceling headphone that has been able to compete with the likes of Bose and Beats.
Its look may not be all that pleasant, but it’s well-built, has a sort of ungainly business professional vibe and is comfortable to wear. It’s slightly heavier, weighing in at 340 grams or 12 ounces than the Bose.
The headphone comes with a cable and an in-line remote/microphone which allows you to use them as wired earphone or when the battery dies mid-flight. It folds flat and come with a carrying pouch.
Its buttons are located on the ear cups which makes it easy to be operated blindly, with a ring on the left ear cup serving as a transport control (track skip forward and back), and a ring positioned at the right ear cup serving as a volume control.
It has a sensor which pause your music when you take the Pro off your ears and rest it around your neck and resumes play when you put the headphones back on.
The Plantronics BackBeat Pro also functions well as a headset for mobile phones. Its built-in microphone allows for taking calls.
This headphone features the NFC tap-to-pair technology for Android phones and its advanced Bluetooth technology extends the wireless Bluetooth range to up to 100 meters (330 feet) when using a tablet or a smartphone that supports the technology (this is 10 times as much as the usual 10-meter (33-foot) Bluetooth range) and its .
The BackBeat Pro is AptX-enabled, which allow for better sounding audio streaming over Bluetooth.
AKG N600 NC
(Best Noise Cancelling Headphones )
The AKG N60 NC can only feature in as best noise canceling earphones for good reasons. It’s a comfortable, compact, noise canceling on-ear headphone that has a 30-hour rechargeable battery life and sounds great. However, its single-button remote lacks volume control and the charging cable isn't the standard Micro-USB variety.
This headphone is of smaller on-ear headphone, which makes it suit better to smaller heads, weighing just 179 grams or 6.3 ounces, little less expensive, and folds up and flat to fit in an included neoprene carrying case.
The main reason why it’s considered one of the best noise canceling on-ear headphone is simply because it offers cleaner and well-balanced sound with smooth treble, tighter bass and a warm mid-range as compared to Bose although being less comfortable to Bose. However, it's very convenient for an on-ear headphone with its well built-in soft leather-covered ear cups.
PSB M4U 2
(Best Noise Cancelling Headphones )
The PSB Speakers M4U 2 Active Noise Canceling Headphones is considered one of the best wireless noise canceling headphone as it combines above-average noise cancelation with excellent sound quality that's well worth the price for dedicated audiophiles looking to eliminate ambient noise, it keeps working even after the batteries have drained. However, it’s more expensive ($399.99) than most noise canceling headphones.
The new PSB Speakers' M4U 2 active noise canceling headphones superior sound and engineers' smart design choices put the M4U 2s at the top wireless noise canceling headphone. It’s fairly compact for a full-size, over-ear design.
The PSB M4U 2 model's "active" noise canceling technology or powers is great and it's also regarded as the best-sounding pair of earphones of its type. The mid-range, treble, balance, and bass are flawless, thus; it sounds excellent with jazz, classical, rock, electronica, and in fact every form of music.
The M4U 2s noise canceling headphones are among the best-sounding headphones in the market and certainly worth the money for audio-conscious music lovers who want to completely keep-out of noise. It uses four noise-canceling microphone systems. Two on each ear cup, which allows for a more accurate processing.
M4U 2s has a silver black plastic, metal headband that feels fairly durable and comfortable to wear with its gyro-suspended ear cup mounting system which allows the ear pads to swivel laterally and vertically for an optimal fit.
The switch located on the right ear cup allows for easy turning the noise cancelation on and off and a third position that activates the internal amplifiers. However, the sound is amplified with any noise cancelation, which allows the headphones to play louder while conserving the battery.
PSB comes with two 55-inch cables included for BlackBerry and Apple devices and controls on the wire for accessing the in-line microphone and navigating music tracks. Also included are an extra set of user-replaceable ear cushions, a semi hard zippered travel case, an airline adapter and a 3.5mm-to-6.3mm plug adapter.
The M4U 2 comes with a two-year labor and parts warranty. To initiate a warranty claim, you'll need to provide a proof of purchase or invoice.
PSB M4U 2 is priced at $399, thus; making the PSB Speakers' M4U 2 Active Noise Canceling Headphones to be considered as one of the most expensive pairs of active noise canceling headphones in the market. However, they have some of the best technologies that make them stand out among headphones and therefore are worth the extra bucks. One of these technologies is the ability to still play music after the batteries are drained. That said, if by chance you are in the market searching for the best active noise canceling headphones, with excellent sound quality, the PSB M4U 2s are the pairs to buy.
Bang & Olufsen BeoPlay H8
(Best Wireless Noise Canceling Headphone)
Our next wireless Bluetooth noise canceling headphone is the Bang & Olufsen BeoPlay H8. This is a sleek design with a leather/metal headband, which features plush ear cups, touch controls in the right ear cup, active noise canceling, replaceable, rechargeable battery, 14 hours of battery life, and very good sound for Bluetooth.
The Bang & Olufsen BeoPlay H8 is an expensive ($500) wireless Bluetooth noise canceling headphone. However, it is equipped with a plush sheepskin ear cups that has memory foam, designed with a sturdy metal and leather headband, relatively compact, lightweight (weighing 255 grams), and place at the high end of the wireless Bluetooth headphone spectrum.
It has an effective and efficient touch sensor located on the outside of the right cup (though you can accidentally pause or play your music while removing the headphone), with simple operation control to answer calls, change songs and adjust volume.
It has a 14 hour rechargeable, replaceable battery life which improves dramatically (up to 35 hours) if you turn Bluetooth off but use on noise canceling wired mode.
The H8 has a great sound quality with lots of bass, good clarity and fairly warm mid-range. However, it sounds better as a wired headphone.
Bose QuietComfort 20
(Best Wireless Noise Canceling Headphone)
The Bose QuietComfort 20 and 20i are amongst the best noise canceling earphones which are compact in-ear headphones. That offers excellent sound quality, very comfortable to wear and provides a surprisingly impressive noise cancelation which is powered by an integrated rechargeable battery that delivers up to 16 hours of battery life. However, they are expensive to buy. Their rechargeable battery isn't replaceable and don't sound as lovely as many competing in-ear headphones in this price range.
Bose 20 has been a go-to choice of noise-canceling earphones that comes in two versions. The standard QC20 (non-Apple products) and the QC20i (for use with Apple products). The QC20s are very comfortable to wear, very light weight (just 1.5 ounces), and features two microphones to help monitor external noise. They come in 3 sizes and a 16-hour rechargeable battery life that is charged through the standard Micro-USB cable.
They contain a smaller second remote for controlling volume, a switch for toggling and a microphone for making phone calls at the Y-cable joint leading to the left and right ear buds.
When set on the "Aware mode", it significantly reduces noise cancelation, allowing you to hear the outside world.
It’s excellent at noise cancelation, though a more loose-fitting ear bud.
The sound is quite good, decent, nice and smooth but not as much expected from such an earphone. However, once you turn on active noise canceling and all the digital processing, it brings you to a little bit of loose sound quality.
Noise-canceling earphones usually don't sound as clear or clean as "passive" headphones, and some even introduce a faint hiss (this hiss is very minimal with the QC20s).
(Wireless Bluetooth noise Canceling Headphone)
The Sony MDR-ZX770BN is a well-designed wireless Bluetooth noise canceling headphone that worth the money and is geared towards frequent travellers. This is because it can also work as a wired headphone on flights that prohibit the use of Bluetooth and has active noise-cancelation with three ANC modes. However, it doesn’t seems to be what it is in terms of appearance when we talk of the premium headphone and its 3 sound modes can be more confusing rather than convenient.
The Sony MDR-ZX770BN is a quality Bluetooth headphone with an active noise-canceling.
It's very comfortable to wear, has memory foam in the ear pads, reasonably lightweight (around 240 grams or 8.5 ounces). It has well-located tracks and volume control on the right ear cups with a pause button which also serves as the answer/end calls button.
It also features the Near Field Communication (NFC) tap-to-pair technology for automatically pairing the headphones to Android and AptX for smartphones that supports it to enhance the quality of Bluetooth.
Its 13 hours battery life with noise-canceling and decent Bluetooth turned on which comes in different colors plus USB charging cable and a headphone cord.
Bose QuietComfort 25
(Top Wireless Noise Canceling Headphone)
The Bose QuietComfort 25 is totally redesigned from the QuietComfort 15, with better audio performance and noise reduction, featuring an advanced design that doesn't put off the music when the battery dies.
This headband is covered in an "engineered fabric found only in high end automotive applications." Its ear cushions are made of leather and has the same luxurious touch as expected from any Bose and the "pivot" or hinge in the ear cups are made out of "cast-zinc" which makes them sit closer to the head and more comfortable to put on.
This Bose headphone has a good balance between durability, weight, and comfort level.
The QC25 is powered by a single AAA battery that offers up to 35 hours of use with noise cancelation on. However, if the battery dies, the music plays on. Although the sound may be a little weird without power you can still get sound out of the QC25, that notwithstanding.
It also features an in-line microphone and remote for taking calls with recent iPad, iPhone, and iPod models, as well as smartphones. However, some of the remote features may not work with Windows and Android devices but the microphone will.
A great "feature" of these headphones worth mentioning is the Bose's satisfaction guarantee. If you're not totally satisfied with this product, you can return it (or as well as any Bose product) for a full refund. It has a trial period of 30 days in the UK and US and 21 days in Australia.
The QC 25's case has slots for storing an extra battery, and two prong adapter for airplane users. The inside case has a diagram that illustrates how the headphones should be folded to fit inside the case which is very helpful.
Bose QuietControl 30
(Best Wireless Noise Canceling Headphone)
Here comes one of our top wireless noise canceling headphones. The Bose QuietControl 30 is a very comfortable to wear, well-built, excellent sound quality for a Bluetooth headphone and offers variable noise-canceling. The QuietControl 30 works really great as an everyday headphone and thus can be used for all sorts of sporting activities. However, it’s not that great or effective at noise canceling as compared to the QC 35 or QC 20 and has no wired option to plug into airline or used in airlines that prohibit Bluetooth used in flight.
The QC 30 has an adjustable noise cancelation which allows you to either lower or raise it by pushing through the Bose Connect app for Android and iOS devices or a set of buttons on the in-line remote. This is why it is called the QuietControl. The noise canceling can really be cool when you raise it to the highest volume but if you’re running, you need to reduce the volume for high-way security purposes.
It has 10 hours battery life as rated at, decent for this type of Bluetooth headphone and a protective carrying case is included.
The Bose QC 30 is sweat resistant for which reason you can use it for running or at the gym.
The downside to this headphone is that it allows some ambient sound leakages, which negatively impact your music-listening experience in noisy environments. But this ambient sound is greatly reduced by its noise canceling technology. Also, you will not be able to use this headphone in airlines that prohibits the use of Bluetooth on-board since it has no wire connection.
While the QC30's noise-canceling isn't quite as effective when compared to the Bose QC20 or QC35, it's comparatively better than most noise canceling earphones in the market. It muffles a lot of ambient noise which makes it a preferred choice for most people.
Safety and Precautions
Don’t use noise canceling headphones on the highway or streets. This is dangerous and may put your life on the line since it puts away sounds or ambient noise. This will mean even the sound of cars coming behind you will not be heard. If you must use it during any sporting activities for more fun, don’t turn off all ambient noise and keep-off the motorway. You can safely run along the pedestrian paths.
High music volumes are not healthy to your ear drums especially for elderly people. We recommend you to always use a moderate volume while listening to music using your headphones.
You have gained much going through our collections of Active Noise Canceling Headphones, most of which works as both wireless Bluetooth noise canceling headphones and wired noise canceling headphones. The best way to taste any of these headphones (or any noise canceling headphone) is to wear them in a crowded and noisy place such as the market or if you are opportuned to work at an airport then I suggest you try using them around the plane’s engine. Having a nice pair of noise canceling headphone is usually an expensive buy (typically above $200), thus one has to be extremely cautious of what he gets. Well, you must remember that your taste for sound may be different from ours, we did all what we could to come out with the best among equals.