Sennheiser HD 4.40 BT Pros&Cons


  • Well-priced
  • Has AptX
  • Very decent battery life
  • Can connect analogue cable


  • Pretty “average” audio quality

Sennheiser HD 4.40 BT Specs

  • Impedance: 18Ω
  • Frequency response: 18 Hz ~ 22 kHz
  • Sensitivity: 113dB / mW
  • Battery life: Up to 25 hours
  • Support Codec: AptX


The HD 4.40 BT’s packaging design is very recognisable, in the sense that it has a very typical Sennheiser look – mostly black, with a touch of Sennheiser Blue.
The front displays a large image of the product, along with some text and images to showcase the HD 4.40 BT’s foldable design, wireless capability, and maximum battery life.


The left side of the box advertises the HD 4.40 BT’s compatibility with Sennheiser’s CapTune app (available for both iOS and Android), as well as what accessories are included with the HD 4.40 BT.

The right side has another few logos and text to highlight the HD 4.40 BT’s wireless capabilities (including NFC pairing and AptX), as well as a QR code to enable you to scan and check for the product’s authenticity

The rear describes some of the HD 4.40 BT’s features and sonic qualities in 7 different languages, along with some of the audio specifications.


What’s in the box?

  • Sennheiser HD 4.40 BT
  • Storage pouch
  • 3.5mm stereo cable
  • Micro-USB charging cable




The HD 4.40 BT really doesn’t include much other than the absolute bare essentials, really. Ok, the little storage pouch is a nice touch, but it’s just a bag. There isn’t even an airline adapter for stereo analogue connections. But then again, this is a Wireless set of headphones that feature both AptX and NFC for only $150.

Read: Sony MDR1000x Noise cancelling headphones Review


The HD 4.40 BT definitely has quite an understated and stealthy look. Heck, even the Sennheiser branding is kept in a rather minimalistic fashion.

One thing that must be said, though, is that Sennheiser managed to make the HD 4.40 BT feel quite sturdy despite being predominately made of plastic. There really is very little creaking from the HD 4.40 BT.

Sennheiser have also designed the HD 4.40 BT to be able to fold into a pretty compact package for storage/travel use.


The left earcup is where Sennheiser have placed the NFC chip, making pairing very simple for Android devices. Here Sennheiser have a little trick up their sleeves too. The great thing about NFC is that the chip doesn’t require constant power. In fact, the only time it needs power is when it communicates with an NFC reader, in which case it gets the power it requires from that same reader. In the case of the HD 4.40 BT, you can scan and begin the pairing process simply by touching the compatible Android device to the HD 4.40 BT’s left earcup. However, the HD 4.40 BT doesn’t need to initially be powered on, as the action of scanning the NFC tag also power’s on the HD 4.40 BT and puts it into Bluetooth pairing mode. On other devices, they need to initially be manually turned on in order to perform the actual pairing, as scanning the NFC chip only passes the device’s info to the NFC reader. So that’s a pretty nifty little feature from Sennheiser.

The right earcup houses the power button, skip forward/back slider, volume rocker, stereo analogue port, microUSB charging port, as well as dual omni-directional microphones used during calls. Here we can see that Sennheiser skimped out a bit on the design, especially with regard to the skip forward/back slider. It’s a slider, not even a rocker button. But perhaps more annoying is the fact that it doesn’t operate in an intuitive manner. To skip forward to the next track, you slide the switch towards the back/up, and of course the inverse to skip back. It also doesn’t seem possible to use this slider button to ffd/rwd within a track.

The HD 4.40 BT is a really comfortable set of headphones, though. Initial clamping force is slightly on the higher side, but those earpads are really, reeeaaaally nice. Whilst the inner portion of the pads do look  to be on the small side, they actually form nice over, around, and behind the auricle. The pads are also thicker than normal, which tends to give the HD 4.40 BT a bit of a larger profile on the head when worn.
One downside seems to be with the padding use don the headband. Here Sennheiser have gone for what seems to be some sort of rubberized coating. The negative to this is that the makes the headband rather grippy, meaning that dust and lint tends to accumulate. But it also means a mild amount of discomfort can be experienced ever now and then, as the grippy texture can sometimes get hold of you hair and pull on it.


Test Setup
Source: Shanling M2s, Samsung Galaxy S7
DAC/Amp: IFI Micro iDSD Black Label

For the most part, Sennheiser did a reasonably good job with the sound of the HD 4.40 BT. As we can usually expect in this price range, there is a tendency to go for a a “safe” tuning, which normally involved a mild v-curve signature. The HD 4.40 BT also favours the bass frequencies (below 100Hz), as is usually the case with “consumer-grade-audio”. But the bass does also tend to spill quite a bit into the mids. Daft Punk’s Doin’ It Right, for example, is a pretty good track to check how a set of cans/IEMs handle the bass section. Here the HD 4.40 BT displayed a deep reach, but more importantly it showed just how much the HD 4.40 BT’s tuning favours bass over the rest of the frequency range, and highlighted the fact that things can sound a bit muddy when deep and strong bass lines are called upon.
There seems to be a dip in the mid-range and high mids, which leads to some undesirable effects. This becomes most apparent with vocals, as they can sound a a bit distant and muffled. But perhaps the strangest effect is that it can make vocals (especially female vocals) sound rather “nasally”. The HD 4.40 BT changed that sweet and lush quality of Melissa Menago‘s voice, for example, which lead to her almost sounding like Fran from The Nanny. Ok, that’s totally wildly exaggerated, but the point still stands that the HD 4.40 BT doesn’t portray vocals with a very natural presentation.

In wired mode the HD 4.40 BT does appear to sound a little cleaner, although this may very well be due to a slight volume change too. As such, the overall sonic character seems to be unchanged, and thus you won’t really be gaining anything as far as audio fidelity is concerned if you were to opt for wired over wireless mode.

hd-440-topRead: Sennheiser PXC 550 Wireless Headphones Review


So, at an asking price of around $150, is the HD 4.40 BT worth it? To be quite frank, there aren’t that many headphones in this price range that offer AptX connectivity. But, those that are available, are ones to consider. The fact is that the HD 4.40 BT compromises on sound quality in favour of wireless freedom. This isn’t necessarily a bad thing, as such compromise are entirely a subjective matter. To one person a compromise on sound quality would be an absolute deal-breaker, whereas another person may very well appreciate the wireless functionality more. If you tend to fall more inline with the latter, then the HD 4.40 BT does seem to offer up some decent value.


The TECH MERIT rating system is designed to take as many aspects of the device into account as possible. As such, we have a basic rating, as well as a final rating. The basic rating rates the product purely as a high quality portable audio device, and is generally a good indicator of how it stacks up to its rivals in terms of standard features and specs. The final rating, however, grants bonus points for any extra features and specs that aren’t quite as common, and is a great way to judge the product as a complete package.

Look and feel: 8 / 10

Included Accessories
Protective case: YES

Quality control: 9 / 10
Seems durable: YES
Microphonics: 8 / 10
Comfort: 9 / 10

Relatively balanced signature: –
Soundstage: 7 / 10
Detail retrieval: 7 / 10
Sibilance: 9 / 10
Instrument separation: 7 / 10
Isolation: 8 / 10
Hiss: 9 / 10

Small size: 7 / 10
Relatively low power required: 8 / 10
Weight: 9 / 10

Competitive price-point: YES
Relative value: 8 / 10

Basic Rating: 7.7

Bonus points
Removable cables: YES
Number of cables included: 1
Premium cables: –
How premium the case looks and feels: 2 / 10
Battery life above 8 hours: YES
Bluetooth: YES
Apt-X: YES
Volume/remote controls: YES
Metal body: –
Premium look and feel: –
Use of exotic materials: –
Bluetooth connection quality: 9 / 10
1/4” adapter included: –
Cable management: YES
Aircraft adapter: YES
Extra earpads: –

Final Rating: 7.9


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