Sennheiser HD 4.40 BT Wireless  Headphones Review

The Sennheiser HD 4.40 BT look fairly similar to the Sennheiser HD 4.50, but they don’t have silver accents on the ear cups and headband, which makes them stand out a bit less. They are fairly low-profile over-ears and don’t have a very flashy design. The padding is decently thick on the ear cups, but there’s not much on the headband. The dark matte finish gives the headphones a high-end look but might feel a bit plasticky once in your hands.

The Sennheiser HD 4.40 are decently comfortable and have good padding on the ear cups. They feel a bit softer than the Sennheiser HD 4.50, but they are noticeably less tight, which people may prefer. The headphones are lightweight and don’t apply too much pressure on the head, which is good since the headband isn’t well-padded. Also, the cups are fairly small and shallow and might not be very comfortable for people with bigger ears. These headphones might get uncomfortable for long listening sessions.

The HD 4.40 BT don’t have the best control scheme and have similar flaws to the Sennheiser HD 4.50. The buttons are the same, and they feel cramped and unresponsive at times. You get call/music management, track skipping, and volume controls, which are common. However, the track-skipping switch also acts as a button to play/pause, so it feels very mushy and feedback is poor. On the upside, the volume rocker is good, but you get an audio queue for each volume change, which can get annoying.

The Sennheiser HD 4.40 are not very breathable. They have a tight fit and a decent seal around your ears which obstruct a good amount of airflow. They should be okay for casual listening and most use cases, but will make your ears sweat during more demanding activities like running and exercising.

The HD 4.40 BT are not the most portable over-ear headphones, but they can fold into a more portable format, which takes less space. However, the cups don’t swivel to lay flat, which would make them easier to slide in a bag or to wear around the neck.

These headphones come with a soft pouch that protects the headphones from small scratches but won’t protect against water exposure and physical damage if they are dropped. On the upside, the pouch doesn’t add bulk to the design.

The HD 4.40 and 4.50 are built the same way. They are lightweight but feel fairly durable. The cups feel dense and should survive a few accidental drops. However, the headband isn’t reinforced by a metal sheet like the higher-end Sennheiser PXC 550 Wireless. Overall, they feel a bit plasticky, but they don’t feel too cheaply made.

The Sennheiser HD 4.40 are stable enough for you to run with, but they still won’t be the best option for exercising or intense sports due to their bulky over-ear design. They aren’t as tight as the HD 4.50 and fall off your head more easily. On the upside, the wireless design also ensures that the headphones won't be yanked off your head, as there's no cable to get hooked on anything.

• Sennheiser HD 4.40 BT headphones
• 1/8” TRS audio cable
• Micro-USB charging cable
• Carrying pouch
• Manuals

The HD 4.40 BT have a mediocre frequency response consistency performance. These headphones are prone to consistency issues, especially in the bass range. The maximum variance measured across our five human subjects was about 8dB at 20Hz, which is noticeable. We also noticed that certain types of glasses could break the seal on these headphones and cause a drop in bass. In the treble range, they delivered fairly consistently but might be a bit sensitive to positioning. Try the Samson SR850 if you're looking for over-ear headphones that deliver sound more consistently.

The Sennheiser HD 4.40 have excellent bass. LFE (low-frequency extension) is at 10Hz, which is excellent. Low-bass, responsible for thump and rumble, is overemphasized by almost 4dB, which adds a noticeable excess of thumpiness to the bass, but some may prefer this. Mid-bass, responsible for the body of bass guitars and the punch of the kick drums, is also overemphasized by more than 2dB. There’s also a small dip in high-bass, which results in a slight loss in warmth.

Also, their bass delivery varies noticeably across users, and is sensitive to the quality of fit, seal, and whether you wear glasses. The response here represents the average bass response, so your experience may vary.

The mid-range is great. There’s a small dip in low-mid as a continuation of the high-bass, which makes the vocals slightly thin. However, low-mid and mid-mid are well-balanced and within 1.5dB of our target. This is important for clear reproduction of vocals and lead instruments. High-mid, however, is over our target by more than 2dB, bringing a bit of excess intensity and projection to vocals/leads.

Like the Sennheiser HD 4.50, the HD 4.40 BT’s treble range is mediocre. The response throughout the range is fairly uneven and very underemphasized. The dips centered around 4.5kHz and 7.5kHz have a negative effect on the clarity and presence of vocals, leads, and cymbals.

The Sennheiser HD 4.40 have good imaging. Weighted group delay is at 0.35, which is good. The GD graph also shows that the group delay response is entirely below the audibility threshold. This results in a tight bass and a transparent treble reproduction. Additionally, the L/R drivers of our test unit were well-matched in frequency, amplitude, and phase response, ensuring accurate placement and localization of objects (voices, instruments, and video game effects) in the stereo field. However, these results are only valid for our unit and yours may perform differently.

The Sennheiser HD 4.40 BT have a sub-par soundstage. The PRTF graph shows an inadequate amount of pinna activation with low accuracy, and there's no notch present in the 10kHz area either. This suggests a soundstage that will be perceived as small and located inside the listener's head as opposed to in front. Also, since they are closed-back headphones, their soundstage will be perceived as less open-sounding than that of open-back headphones.

Their noise isolation performance is poor. Since they don’t have an active noise cancelling system, they don’t isolate against low-frequency noises like the rumble of airplanes and bus engines. In the mid-range, important for blocking out speech, they reduce outside noise by more than 10dB, which is okay. In the treble range, occupied by sharp S and T sounds and A/C noises, they isolate by over 31dB, which is good.

The leakage performance of the HD 4.40 BT is good. The significant portion of their leakage is between 450Hz and 2.5KHz, which is not too broad. However, the overall level of leakage is very low. With the music at 100dB SPL, the leakage at 1 foot away averages at about 35dB SPL and peaks at 45dB SPL, which is slightly quieter than the noise floor of an average office.

The recording quality of the mic is sub-par. The LFE of 306Hz results in a recorded/transmitted speech that sound relatively thin. The HFE is at 3.3kHz, making speech noticeably muffled and lacking detail. The response between the LFE and HFE points is quite uneven, suggesting an unnatural speech transmission.

The integrated microphone of the HD 4.40 is decent at noise handling. It achieved a speech-to-noise ratio of 20dB in our SpNR test. This means it will be able to fully separate speech from ambient noise in moderately loud environments but will struggle in loud places like a subway station.

The HD 4.40 BT have a great 29-hour battery life. This will be more than enough for a normal workday, and you won’t have to charge them often. When you do, they only take about 2 hours to fully charge. Unfortunately, they don’t have a power saving feature, so be sure to turn them off when not using them. On the upside, you can use them passively with an audio cable even if the battery is dead, which is convenient. For an even longer battery life, take a look at the JBL Live 500BT.

Unfortunately, the Sennheiser companion app for these headphones, known as CapTune, is no longer available. The replacement app, Sennheiser Smart Control, isn't compatible. If you still have CapTune on your phone it will continue to function, but it's no longer possible to download it.

These headphones are Bluetooth compatible. While they can’t connect to two devices simultaneously, they support NFC for a quicker and easier pairing procedure. If you really care about multi-device support, then consider the Sennheiser HD 4.50 BTNC instead.

The latency of the HD 4.40 is good for Bluetooth headphones, which normally average around 200-220ms of delay. However, this will still not be optimal for watching videos and gaming. On the other hand, they support the aptX codec, which may give you an overall better performance and slightly lower latency, provided you have the right dongle/transmitter. Also, some apps and devices offer some sort of compensation, so you might not even notice the delay that much.

You can use the included 1/8” TRS audio cable to use these headphones passively on pretty much any platform that has a headphone jack. However, their cable does not have an in-line microphone.

These headphones do not have a dock. If you're looking for headphones with a dock for customization options, look at the Arctis Pro Wireless. If you want a charging dock, look at the Astro A50, and if you're looking for wireless headphones for watching TV, look at the Sennheiser RS 185.