Sennheiser HD 400U review: Refined German sound for under $100

The Sennheiser HD 400U headphones are a set of entry-level wired cans offering the German brand’s renowned sound quality in a no-frills package, and at an affordable price. They’re an update to the Sennheiser HD 400S, this time featuring USB-C wired connectivity instead of 3.5mm, making them better equipped for day-to-day use with smartphones.

Now, when I say no frills, I mean it. There’s no wireless connectivity, no ANC, no EQ, and barely even any padding on the headband. What these headphones lack in features, though, they make up for with strong core performance, with a bass-forward sound profile, but respectably well-defined mids and bright treble.

If you’re on a $100 budget or want to experiment with a premium headphone brand without dropping several hundies, the HD 400U could be some of the best over-ear headphones for you.

Find out more in my full Sennheiser HD 400U review.

Sennheiser HD 400U review: Cheat sheet

• What is it? A pair of entry-level over-ear headphones from Sennheiser
• Who is it for? People who want to experiment with premium sound at an affordable price
• What does it cost? $99 / £69
• What's good? The sound quality, USB-C connectivity and reasonable price
• What's not? The plasticky build, scratchy mic and small earcups

Sennheiser HD 400U review: Specs

Sennheiser HD 400U review: Price & availability

• Properly budget in the U.K.
• Not that budget in the U.S.

The HD 400U cost $99 at Amazon in the U.S., making them slightly pricier than their predecessors, the Sennheiser HD 400S, which launched at around the $80 mark (but can now be found for around $60). While affordable, $99 isn’t that cheap. There’s an argument that $99 could count as either ‘high budget’ or ‘low mid-range’, but I’ll give them the benefit of the doubt and say the former.

In the U.K., the HD 400U are priced genuinely keenly at just £69 from Amazon, making them an incredibly affordable way to experience premium sound.

The HD 400U have some pretty tough competition, namely from the budget studio market. The FiiO JT1 cost just $69, the Sony MDR-7506 sit around the $115 mark, while the Audio-Technica ATH-M50X and Beyerdynamic DT 270 Pro both cost $159. All four are studio headphones with a more neutral (less bassy) sound profile, and all use 3.5mm cables, suiting them less to everyday use with a smartphone. For a set of day-to-day cans, I’d choose the Sennheisers over all of these, primarily for that USB-C connection.

Also splashing around in the sub-$100 market are the JT1’s open-back cousins, the fantastic FiiO JT3 ($69), although as open-backs these aren’t suited to outdoor use. If you’re after a set of home-use headphones, though, the JT3 would be my suggestion.

Sennheiser HD 400U review: Design & comfort

• Built to a budget (despite costing $100)
• Earcups nicely padded but very small
• Collapsible for portability

Design is where the HD 400U’s budget nature rears its head most clearly. The headband padding (if you can even call it “padding”) looks like something from a $10 conferencing headset — it’s about as meaty as a bus full of vegans. Push it even gently with your finger and you can feel the plastic underneath.

That said, the headphones are super lightweight, so the headband doesn’t dig into your scalp. It just looks cheap and flimsy, as do all the plastics used in the exterior construction, for that matter. It all shouts budget, which I guess the HD 400U are… in the U.K. at least. In the U.S., though, I’d expect a little better for $99. While the HD 400U aren’t uncomfortable, they still aren’t decidedly pleasant to wear. As proved by the $69 FiiO JT1 and JT3 — which both feature gloriously comfortable suspended headbands and soft, plush earcups — ‘budget’ needn’t mean ultra-basic, and can still feel luxurious to wear.

While not strictly a budget issue, the HD 400U earcups are also plain awkward. The padding is fine — good, even — but the ear recesses are tiny. I don’t have especially big ears, but I’ve been unable to get my ears into the recesses properly without lots of maneuvering, the result being that the cans sit more like on-ears than over-ears. To check whether this was a ‘me’ issue, I handed them to our senior writer Erin Bashford, who by her own admission has notoriously small ears: she couldn’t get the HD 400Us to sit comfortably either. If you have long and/or big hair, like me and Erin respectively, the earcups are especially problematic, as it gets even harder to tuck your ears inside the cups.

On a positive note, the headphones use a folding design, making them easy to collapse and transport in your bag using the soft carry pouch. Again, the construction is pretty flimsy-feeling, so I wouldn’t put the headphones at the bottom of my bag for fear of them getting crushed.

Sennheiser HD 400U review: Connectivity

• USB-C cable good for smartphone users
• Could theoretically fit a 3.5mm cable
• Inline remote/microphone

The HD 400U are wired headphones, which is both limiting and not! Wired cans obviously lack the versatility of wireless headphones, but the benefit is that you can stream audio in full resolution without the compression of Bluetooth. There’s also a pleasing simplicity in wired cans — they’re plug and play, there’s no messing about with connections and no need to recharge or worry about battery life (although obviously wired cans draw power from your playback device). If you decide that the wired life isn’t for you, check out the $99 Soundcore Space One or the $79 (and oh-so-catchily-named) JLab JBuds Lux ANC headphones instead.

The HD 400U feature a USB-C cable, replacing the 3.5mm jack of the older HD 400S. This suits the new model much better to modern smartphone usage, where 3.5mm ports have been almost universally displaced. The cable is removable, though, so you can replace it if damaged, or even swap in a 3.5mm optical cable (i.e. from the HD 400S) if you want.

The cable features an inline microphone and remote, with a single button for playback controls. A single press plays/pauses media (or answers/ends a call), while a double press skips a track and a triple press skips back. This worked fine on my iPhone 17 Pro Max, but I wasn’t able to get the skip/rewind function working on my MacBook Pro.

Sennheiser HD 400U review: Sound quality

• Bass-forward sound profile
• Clear treble and respectable definition in mids
• Best for heavy pop and bassy stuff

The Sennheiser HD 400U sound quality is solid. These cans won’t set the world alight in any regard, but for the money, they’re absolutely fine. I tested the headphones by streaming through Qobuz — in our opinion the best music streaming service for audiophiles. I streamed a mixture of 16-bit 44.1kHz CD-quality, 24-bit 48kHz, and 24-bit 96kHz hi-res.

I’ll get it out of the way early: the sound profile of the HD 400U is noticeably bass-forward, which is fine — that’s what a lot of consumers want and the HD 400U sound great for casual use. For the most part, bass isn’t overbearing anyway. However, if you’re after a more neutral sound for detailed listening or studio use, look elsewhere. The HD 400U don’t offer the sheer mid-range clarity and ultra-crisp treble of studio-oriented competitors, like the Sony MDR-7506 or Beyerdynamic DT 270 Pro.

Pop

Heavier, electronic pop sounds great through the HD 400U. The slightly distorted, synthy bassline of Chappell Roan’s Red Wine Supernova thrummed through all rich and fuzzy, as the artist intended. Highs were nice and prominent, with Roan’s energetic vocals sounding tight — especially the squeakier harmonies towards the end of the track. And mids sounded fine, too, although some of the mid-tone fuzziness of that bass distortion felt a little lost versus through the Sony MDR-7506.

Electronica

Properly bassy stuff is where these cans shine. The thick, undulating bassline and powerful kick drum of Foreign Concept’s Breaking Again (a liquid DnB track) were done full justice, with no distortion to report. Meanwhile, the driving sub-bass of Burn Water’s atmospheric Ikigai vibrated my ears nearly to a tickle. Again, decent treble extension kept the track’s ethereal vocals fairly prominent.

Rock

Next, I put on some rock. Highs were well defined in The Police’s Truth Hits Everybody, with Stewart Copeland’s rollicking cymbals and high hats crisp, yet not piercing. Strong instrument separation was on full display in Tool’s complex Pneuma. And in Melvins’ super-mid-heavy Honey Bucket, with its sludgy, distortion-packed dual guitar riffs, each riff felt adequately separated. Busier mid- and bass-heavy tracks like Honey Bucket were the only places where I found bass a little overbearing and missed the mid-range clarity of studio cans like the MDR-7506.

Soundstage

Admittedly, the HD 400Us aren’t the most jaw-droppingly spacious headphones I’ve heard. Tongue out, brow furrowed and fully concentrating, though, I was nevertheless able to pinpoint bongos and percussion in Mk.Gee’s precisely-spatial Dream police. For sub-$100 headphones, not bad!

Sennheiser HD 400U review: Mic quality

• Tinny, scratchy mic
• Fine for calls if you have nothing else

The Sennheiser HD 400U feature a built-in microphone, which is handy. In test recordings, the mic sounded very tinny and scratchy, with thin vocals. I joined a work call with colleagues and asked their opinions on the Sennheiser’s mic: their feedback was the same.

The HD 400U mic is fine for taking calls in quiet environments, as long as you hold it up near your face, but I wouldn’t want to use it unless I had to, especially outside. I actually chose to use my iPhone’s mic on phone calls, which says all you need to know.

Sennheiser HD 400U review: Verdict

The Sennheiser HD 400U are a solid set of upper-tier budget headphones, offering an updated USB-C interface over their predecessor, while offering excellent sound quality (particularly in bassier tracks). They aren’t perfect, looking and feeling cheap (despite being priced at the very top end of what I’d consider ‘budget’), with questionable earcup comfort and a tinny microphone.

However, I can overlook their flaws, because in the end, $99 is still a fairly reasonable price to pay for audio this refined. If you want great sound without breaking the bank, I’d happily recommend the Sennheiser HD 400U headphones.