A very special pair of aptX Low Latency cans, the Sennheiser HD 450SE headphones offer superb long battery life, active noise cancelling (anc) and multipoint connection! 

The HD 450SE headband ratchet slider band has very long extension, which is perfect to suit tall heads. The ratchet band is made entirely of plastic, just like the HD 450BT version, and weigh the same (240 grams). The lack of metal band reinforcement isn't a deal breaker, although it does help support the headband a bit more and make it more sturdy. Despite not having a metal band though, the HD 450SE headband feels robust and has a medium to high clamping force, which is good for keeping the heavy headset in place. The higher the clamping force the more the earpads press against the ears though, which is usually not comfortable if you have a large head or wear glasses. The earpads can be replaced.


Because the HD 450SE headset only weighs 240 grams though, a lower clamping force would have been probably better since higher clamping force headsets aren't usually comfortable to wear for longer sessions. That said, the HD 450SE clamping force does help maintain a good seal for passive noise isolation, which is really good and helps the performance of the anc. Being PU earpads, you can expect heat build up - a little bit more than usual too because of the clamping force. In cold weather, you don't notice heat as much as a in a warm/hot environment.


The HD 450SE headband isn't foam padded like on most headbands. Instead, the underside of the headband is covered with a thin layer of soft rubber. The lack of foam padding is strange but the extremely low weight (240 grams) prevents developing headband hot spot, which tends to happen with heavier headsets. The earpads have proper memory foam padding, which is thick and firm but supple so, they mold comfortably on the ears. The outer of the ear pad measures 9cm high and 7.5cm wide, while the inner hole measures 3cm wide and 6cm high with 2cm depth to the driver, which is covered with a thin layer of fabric. The HD 450SE headphones are marketed as over-ear style but the inner hole is narrow shaped like an almond. If you have large ears, the earcups won't properly cup your ears.


When it comes to overall design and construction style, the HD 450SE is very similar to the HD 450BT mode. The both have the same smooth matte (non-fingerprint) finish, as well as a plastic folding hinge mechanism that allows the earcups to fold inwards. There is tilting too but the earcups do not swivel flat. The earcups integrate a rocker switch with centre button to control volume, play/pause and calls (accept/reject/end). Every time you adjust volume you hear a single beep and a double beep when reaching max volume. The beep tone feature is useful for telling every level of volume adjustment but it may get irritating for some people and there is no way to disable it.

The Sennheiser HD 450SE headset uses a 2.5mm audio input, which is smaller than 3.5mm. Both are basically the same, except the hole diameter size. The only advantage to 3.5mm is that most regular audio cables use 3.5mm so, if you have one laying around you won't be able to use it with the HD 450SE headset. Interestingly enough, 3.5mm wasn't always the standard. Not long ago 2.5mm was the original standard for phones.

If you like voice command control, there is a dedicated button designed to prompt the voice assistant (Siri, Google or Alexa) in your phone. Alexa voice assistant is built-in but you will need to download the Amazon Alexa app (unless you already have it), as well as the Sennheiser Smart Control app to activate Alexa, which is disabled by default. Once connected, the status led does not flash during audio playback

As far as sound, the Sennheiser HD 450SE are bass heavy headphones, although the heavy bass only kicks in when turning on anc. With anc turned off, the bass becomes balanced with the vocals and instruments.The volume output is louder via wired connection than via bluetooth. You can only play wired audio via the headphone jack. The USB-C port is designed for charging only. Speaking of charging, the HD 450SE headphones charge in just 2 hours and support quick charge (2 hours from a 10 minute recharge). You can use the headphones in wired mode while charging too but not in bluetooth mode. You can also use the HD 450SE headphones in wired mode when the internal battery is flat/empty.


There is no transparency/ambient mode, which is usually standard with most anc headphones. Without ambient mode, you cannot let external sounds into the earcups, which is always good for situational awareness and convenient when talking to people without having to remove the headphones from your head. The HD 450SE have the same feedforward anc design as the 450BT headphones, which means the anc microphone is located on the outside of the earcup.


Being that the HD 450SE are feedforward anc headphones, it is a bit strange that ambient/transparency mode has not been implemented since the anc microphone is already located on the outside of the earcup. While feedforward isn't quite as good as a typical hybrid offering, the excellent passive noise isolation of the HD 450SE earpads helps the active noise cancellation perform better than it would normally at cancelling lower frequency sounds. That said, the overall ANC performance isn't the HD 450SE's strongest selling point.


The HD 450SE strongest selling point are superb long battery life in anc mode at around 29 hours with 50% volume. With anc off, you can achieve around 34 hours. The second strong selling point, it's low latency bluetooth (aptX-LL) which the vast majority of headphones on the market do not support. That said, the choice of aptX bluetooth low latency, instead of aptX Adaptive (which is also low latency) is interesting. This is because, aptX LL is being retired and replaced with aptX Adaptive and the two aren't compatible as aptX Adaptive is not backward compatible.


If you are looking for aptX LL headphones to watch TV via a low latency transmitter, the HD 450SE is a good choice. More so, because there aren't that many aptX LL headphones on the market. If you want to use these headphones with a phone, not much luck there because no smartphone support it (Android or iOS) nor will there ever support it now that aptX LL is being retired. This is a pity because of the super low latency of aptX LL offered (~40ms). AptX Adaptive isn't as good (only ~50-80 ms latency). Standard aptX can only manage ~150ms latency, while SBC around ~200ms. The HD 450SE ANC headphones also supports SBC, AAC and standard AptX.


The Sennheiser Smart Control app is a useful companion. The app does not require an account registration but if you're concerned about privacy you should untick sharing "anonymous data usage". The app is really nice to use. It is simple and uncluttered. You can view battery status, as well as access a 3-band equalizer (bass, treble and midrange) and create your own sound signature, which is nice. There are three preset sound modes to choose from: neutral (balance), podcast (focus on vocals) and movie (bass and vocal elevated). There is no button remapping, which would have been nice to re-assign the voice assistant button with a different function like mute button.


Despite not being marketed for gaming, the HS 450SE are a solid option for bluetooth gaming, thanks to low latency and call control, which lets you adjust the call volume and even mute the microphone.Speaking of calls, the call quality is loud and clear in quiet and loud environments. The noise reduction algorithm doesn't completely remove background noise but does a good job of suppressing it so, your voice comes in loud and clear. The bluetooth chip also supports absolute bluetooth volume and multipoint connection. If you don't need anc but still like these headphones, check out the HD 4.50 SE and HD 4.50BTNC, which are basically a non-anc version of the HD 450SE. Be aware though, that the HD 4.50 SE and HD 4.50BTNC headphones are older models released 3 years ago so, they use bluetoth 4.0 and micro USB charging. 

A zipper softshell (non-padded) canvas tote bag is included to store and transport the headphones. The included carry bag has a small inner mesh pocket and it's very compact, which is nice although a hardshell case is always more desirable for safely transporting headphones around. The dimensions are 9cm high, 18cm long and 12cm wide. Cable accessories are also included: a 1 meter long charging cable (26 grams) and a 1.5 meters long male to male audio cable (3.5mm to 2.5mm connectors) that weighs 12 grams. The cables are are nice quality and Sennheiser branded. You can buy the HD 450SE ANC headphones (model SEBT4) from amazon. Check out the review of the EPOS H3 headset