Sennheiser HD 4.40 BT Headphone review

Sennheiser HD 4.40 BT Headphone review

As a frequent traveler I find my headphones to be a quintessential part of my gear. It allows me to pass the time by pumping my ears with engaging sounds or distort outside noise when in an airport, plane, train, or automobile. Unfortunately the problem I commonly come across when using my excellent pair of wired headphones is that I find myself ripping them out of my ears. An annoying game of restricting my movements to not tug on the wires, being mindful of where the cord sits and finding a subtle place to lay my phone so that I or something else doesn't cause my phone to be hurled across the floor is played constantly. So two years ago I decided to make the dive into wireless headphones and what a strain has been lifted off me.

My newest purchase in the headphone universe is the Sennheiser HD 4.40 BT (all links are amazon affiliate links) headphones that were announced recently at CES 2017 along with a few other models (including wired and noise cancelling models).  Sennheiser is known for making quality audio gadgets that perform extremely well but in the past these devices were aimed at audiophiles, prosumers, and professionals and in turn usually did not sit in the affordable domain. I was in the realm of needing a new pair of Bluetooth headphones and after many days (across many weeks) of research I couldn't really find a pair of headphones that had all the features, quality and reviews to satisfy me. So I decided to go with the HD 4.40, an affordable over-the-ear closed back Bluetooth headphone retailing at $149.99. Even at the wake of buying these headphones I knew I was coming in blind since these were fresh out of the factory but I was hoping I could ride on Sennheiser's great reputation and spectacular review of their previous headphones the expensive Momentum 2.0. At the end of review I was left with with mixed feeling and questions about the Sennheiser HD 4.40 BT headphones.

Build Quality and Feel

The HD 4.40's are well fitting headphones with questionable build materials. The construction of the HD 4.40 is made almost entirely of plastic. Coming from my previous model headphone which was made of metal, cloth material and plastic (for parts that were static) these headphones leave me feeling anxious about its life expectancy. The head band is thin and the stems that support the ear cups are even thinner. I usually try to buy products that seem rigid so that I remove any restraint for "babying" them but in this case I have been careful and they have held up nicely so far. Sennheiser is not known for making products of inferior quality (a company's reputation to quality is something I take into consideration when purchasing a product) yet this is Sennheiser's first step into budget friendly consumer products so time will tell.

 The headband consists of hard plastic on the top and a rubbery material on the bottom. At first my concern was that this rubbery material would pull on my mid length hair but instead it has helped to secure the headphones on my head at the expense of dust and particles sticking to it grippy surface.

The HD 4.40 BT when in thier closed position.

The headphones are quite compact compared to other over the ear headphones and they fold into themselves for easier carrying but make no mistake these are over the ear headphones and are still large. The foam pads are very thick and add a lot to its size. Due to its all plastic design the headphones are also very light.

The ratchet system for adjusting the headbands length is on the frail side and with simple handling of the headphones will adjust randomly. Though this hasn't caused me any issues in terms of functionality as once they are on your head they stay nicely in place. The HD 4.40's ear cups have about 15 degrees of motion of swivel left and right (yaw) and about 45 degrees of tilt up and down (roll). These motions are done independently to each ear cup. The clamping force of the HD 4.40 is weak but sufficient for keeping the headphones in place on your head. I consider myself to have a head on the smaller side so of course clamping force will increase for larger heads.

I have owned a few pair of over the ear headphones yet these ear pads are the softest I have felt. The pads consist of 2.5 cm or 1 inch thick foam wrapped in soft leather. The simple act of softly pressing down on the ear pads causes them to slowly inflate back into form. A very pleasant feeling to the touch and around your ears. The cavity for the ears on the other hand is on the smallish side (an oval hole roughly 2.25 in by 1.25 in or 5.7 cm by 3.2 cm) but with room to expand due to the very soft foam inside the ear cups. One issue I have found was the leather tends to show grease and sweet easily. This may be due to the texture of the leather having a very fine grain. The ear cups are not symmetrical to themselves as they seem to bow out in the back and concave on the bottom of the ear cup. This I'm assuming was to help mold the headphones to one's head without putting unneeded stress at certain points. The foam/leather pads come off but are very tedious to put back. 

When unfolded the headphones headband has a wide silhouette. This is where the weak clamping force comes from as the headphones dont need to stretch as much to accommodate ones head. This creates a comfortable wearing experience. Since the ears cups dont have the capability to sit flat the wide gap between the ear cups allows one to look down when worn around the neck without the headphones getting in the way. This makes them comfortable to wear around the neck or on the head.

The HD 4.40's are very comfortable headphones to wear even for very long periods of time or for someone who wears glasses. They are stable on one's head. In terms of looks I think the headphones look fine. They are a little unimpresice looking but that's better than being ugly.

Features and Accessories

Branding is minimal with just the Sennheiser logo on either side and "SENNHEISER" in dark grey on one side of the headphones.

If you are a traveler then there are some features you may want to look for in headphones. In terms of what features you may get is sometimes (but not exclusively) determined with what type of headphone. For example there are 3 basic types of headphones; in-ear, on-ear, and over-ear. In-ear and over the ear may have the best passive noise cancellation and may be the more conferrable options. Battery life tends to be better for the larger over the ear headphones, then the midsized on ear and lastly the micro in ear headphones. On ear headphones may give you a lot of the over the ear features while having a more compact size. Of course the micro sized in-ear headphones will possess the smallest footprint and weight. 

One important feature I was searching for when looking for my new headphones was it had to have excellent battery life. When I am on a plane for 7 hours and then another 4 hours in an airport I hope that my partially drained wireless headphone will last me until I can get to my destination. The 25 hour battery life touted by Sennheiser for the HD 4.40 BT was an attractive feature. In my non comprehensive battery test these beauties performed around that time. In my opinion this is a great amount of operation time. Charging time takes about three hours according to Sennheiser. 

But along with the battery life of the headphones I wanted a headphone that would help preserve the life of the device providing the music so it was important that the headphone supported Low Energy Bluetooth 4. Headphones die eventually and they don't always die in convenient places so it was also important that the headphones had a Aux port so that I can directly connect them to my device or so that I can connect to the airlines entertainment system. The HD 4.40 had this but with one caveat. These headphones come with a unique cable that is a 2.5mm to 3.5mm locking Aux cable which ultimately means it will only be usable for Sennheiser headphones (due to the locking mechanism). This in my case was not a problem as I always keep that cable in my travel backpack and the battery life of the headphones are superb.

Button layout of the Sennheiser HD 4.40 BT.

Unlike the other HD models introduced by Sennheiser such as the corded HD 4.30 and the noise cancelling HD 4.50 the 4.40 is much more traditional in terms of on-ear headphones. It contains basic controls that allows you to play and pause, adjust the volume, power on and off the device, fast forward or rewind, skip or go back, as well as a few phone features. The 4.40's are also equipped with microphones for taking calls. The microphones perform well and only a minuscule amount of environmental noise is heard during calls. The call quality sounds like normal headphone call quality which if your unfamiliar sounds like one is talking somewhat far from a phone (cross between a good speaker phone and normally resting the phone on one's head). This is not a feature I frequently use as I hate not being able to completely hear what I am saying or the volume at which I am saying it at. The buttons they used for the controls could have been better.  The fast forward and rewind is a slider that I have accidentally pressed while reaching for the volume button. The volume is adjusted thru one button that you press either on the upper side or lower side to raise the volume up or down respectively. To indicate that ones finger is on the upper portion of the button there is a little raised dot that is well pronounced. The power button is small and takes four seconds of pressing to turn on the headphones. I find the style of buttons they used annoying but I am just nitpicking.

One of the more prevalent features of any Bluetooth headphone I believe is the Bluetooth part. In the case of the HD 4.40 the strength of the Bluetooth connection was strong allowing me to go a farther distance than any Bluetooth device I have owned. A distance that I'm sure you will not be going without the Bluetooth transmitting device. There was a few hiccups when playing music every once in a while but I cannot confirm if it was the headphones or the device I was using. You are made aware of when the device is powered by a lovely sounding lady telling you that the device is either on or off, low on battery and if it has paired with something. There is also a light that is displayed that will tell you it is turned on. Besides these clues the device itself does not give much information. The lights never blink again, the headphone doesn't tell you how many devices it is connected to, and the device does not tell you its battery level. Most of what you will need to know will be shown on your transmission device such as an iPhone or Android phone. One may also pair the head phones to an Android device using NFC but this is not something I am familiar with.

As for what is in the box the headphones come with a micro usb cable (Why you no usb-c!), a 2.5mm to 3.5mm locking aux cable of about 3 feet or 1 meter, a micro fiber dust bag, and a few manuals and warranty information. The dust bag will not protect the headphones from hard physical damage but only from scratches and as far as I know Sennheiser does not sell a specific hard case for these headphones. I'm sure there isa hard case that will fit these.

Sound Quality

When it comes to Headphones one quality is king. I wanted my headphones to sound great. If price is a concern for someone then there are more affordable options with stagnant sound and more expensive options that are also bluetooth.

All the headphones I tested. I would say the best contender was the ATH-50x but the others were no slouches. From left to right the Klipsch s4, ATH-M50x, Jabra Move, and the HD 4.40.

I am not an audiophile but I do have the necessary equipment to produce high quality sound thru a decent DAC connected to my computer. But to keep this in terms of travel I strictly listened to these through a wired connection to an iPad and iPhone as well as Bluetooth. With the impedance for these headphones coming in at 18 ohms these cans will serve well with any wired device. Quality is increased when wired to a device and of course you will preserve battery while doing this. I was going to post the results of a sound test I did between the Klipsch s4, ATH-M50x, Jabra Move, and the HD 4.40 but I think that would be a disservice to any of these headphones as I am not claiming to be highly articulate in audio. What I was able to gather was that the HD 4.40 has decent sound but not exceptional. I don't think these headphones will be remembered for sound quality. The bass was lacking, highs were good, the mids were average and the sound stage was not as clear as I would have liked. As for the Bluetooth audio (without aptx which should improve the audio quality) the headphones performed fine. In my opinion the quality of the very highs and very lows were better when wired but still very listenable either way.

If your more interested in the technical this is Sennheiser's official website for the headphones.

I noticed that there a small amount of static that can be heard at low volume or when music is paused. When no sound is playing after a few seconds the speakers turn off and the static dissipates. This static is louder then other headphones I use but for me not loud enough to throw off my listening experience.

While performing the sound quality test I also measured sound leakage (how much sound escapes the headphones which may be picked up by other people in your proximity). In this test the headphones performed very well. Much better than the ATH-M50x and this may be due to the thick foam and its cranial forming shape that help keep the sound in. This also works both ways as these headphones do a fine job at keeping sound out but no substitute for a food pair of noise canceling headphones. Of course noise canceling headphones are more expensive such as the HD 4.50 which retail at $200. I personally have found over the ear headphones to be sufficient for my needs.


When I was doing research for a new pair of headphones only one other headphone really caught my eye. The Plantronics Backbeat pros which were on sale for $120 because Backbeat pros 2's were freshly released. The reviews are great on these headphones as well as having the same features in addition to noise cancelling, automatic pause when you take off the headphones and a more standard 3.5 mm aux port. I'm left wondering if I made the right choice?

The HD 4.40's are the most comfortable headphones I have worn but its build integrity in my opinion is questionable. Sound quality will not blow anyone away and battery life is in the average (yet good) for over the ear headphones. The headphones have all the modern features you would want but use a proprietary audio cable and a last gen charging cable. Should you get them? Well that's a complex answer ("Booo! Cop out! Answer the question!") if you want over the ear headphones then I think Sennheiser's HD 4.40 is an option in the affordable none noise canceling Bluetooth headphone pool. The Sennheiser HD 4.40's did leave me a little underwhelmed but still a very viable option for people looking for a new pair of over the ear Bluetooth headphones. 


Update: I updated all the links to be Amazon affiliate links. If you want to support and are interested in a product then use those links to purchase.

Update: So I found out that Sennheiser has an app called CapTune. In this app you can play music from your device or from TIDAL, a music streaming service. Through the app you can change the equalizer to produce a sound more to your liking. Using the app I was able to adjust the sound but does not change the fact that I was slightly underwhelmed with the sound from the headphones. This app at the moment only supports TIDAL and local music so you wont be able to play music from apps such as Spotify or Pandora.



Questionable build materials

Underwhelming sound

Weak band adjustment mechanism 

Unique aux port

No hard case

Minimal information thru the device


Very comfortable


Good battery life


Aux port

Very low impedence 

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