Sennheiser HD350BT Review

The HD350BT on its side

There’s just something about the new Sennheiser HD350BT.

It’s not perfect. There are certainly some areas in which it’s lacking. But upon first putting them on my head, I was struck by the HD350BT’s fantastically expansive soundstage and light, airy sound signature.

Usually, when I try a $120 pair of Bluetooth headphones, I listen to them long enough to get a good idea of the sound signature, skipping between my typical test tracks, write down my impressions, and then take them off my head and put on one of my better audiophile-grade wired headphones while I spin my notes into a full-fledged review. These, on the other hand, weren’t going anywhere.

Don’t get me wrong. Like I said, these aren’t perfect. There are problems. But there’s also an addictive quality to these headphones that can’t be denied, and for $120, it sounds fantastic.

The HD350BT all folded up

IN the BOX

At $120, the HD350BT is a truly barebones affair – it includes practically nothing but the headphones. Since it has the form factor of a portable headphone, I would’ve liked to see a case, but with a cheap pouch already available for the identically-sized HD4.50BTNC, it’s not the world’s greatest sin of omission. At least it’s easily correctable.

– Headphones
– Charging cable (USB-A to USB-C)
– Quick guide and safety guide
– That’s it!


The HD350BT is built with predictably cheap materials, mostly plastic and rubber. Visually, it’s unsurprising, going with most of the same visual cues as Sennheiser’s other recent Bluetooth headphones. No, Sennheiser hasn’t created the “hot new look of 2020” with these headphones – instead, it carries the utilitarian profile that Sennheiser is mostly associated with. You may like it, you may not. One thing’s for sure, though: these headphones are available in white and black.

When it comes to fit, I have to say that the HD350BT didn’t impress me. The headband, with its scant rubber padding, tended to make contact with a single point of my skull, meaning that while it was never too bothersome, it also didn’t “disappear” the way some headphones do after some time. More importantly, though, the earcups were simply too small for my ears. For me, these occupied some middle territory between an over-ear and an on-ear headphone – not the best place to be. It really is just as Mr. Miyagi said.

To somewhat worsen things, I noticed that the sound changes quite a bit with a proper seal – which, for me, as someone with (I guess?) large ears and thick hair, was difficult to accomplish without holding the earcups against my head.

Essentially, if you have big ears, you’re going to want to try these out before you pull the trigger.

The slightly narrow earcup of the HD350BT


As I indicated before, I like the sound of the HD350BT, but for certain reasons that won’t apply equally to everybody. I’d characterize the sound of the HD350BT as overall thin, laid-back and airy. If you’re searching for a headphone with a lot of warmth and body, you can skip to the end of the review now – we appreciate your traffic, but the HD350BT isn’t for you.

Still, this a headphone with a complex and refined timbre that’s worth discussion – and I’m not just saying that because it’s Sennheiser. So I’m going to break this section up into the usual categories.

One thing I should mention before continuing with the review: the HD350BT is a pretty quiet headphone. It doesn’t get quite loud enough for me, so I ended up having to use Foobar2000’s Replay Gain feature to turn up the volume a bit higher. That’s not to say that it can’t handle louder volumes – it did just fine playing louder than it’s used to, but it won’t do it by itself.


As my previous characterization would indicate, the HD350BT is indeed a bass-light headphone. It’s not that the extension isn’t there. There’s rolloff, but this driver does play all the way down to 25 or 30Hz. It’s just that the bass never gets particularly loud or pumping. It can slam a little bit when called for, but it’s always going to be just a bit muted.

I did get the feeling that there was a little distortion happening in the bass, but not anything particularly egregious, especially for this price. With the HD350BT, Sennheiser has done the admirable keeps things restrained, in contrast with the more explosive, sloppy, consumer-oriented bass of some of its competitors.


The HD350BT mostly owes its interesting tone to its uniquely-tuned mids. Essentially, this is a thin-sounding headphone – thinner than neutral, that is – but it manages to pull it off without ever coming off as harsh or unpleasant. In fact, I find this to be a well-balanced headphone that keeps a good balance between instruments, despite lacking some body and power.

Frequency response-wise, what this looks like is an overall recessed lower midrange (until around 1kHz), then a general rise up to about 2.5kHz, before a corresponding fall to about 3.5kHz – at least, that’s what I got from my sine sweeps. I think we can thank the tuning of the mids for granting the HD350BT its unusually large soundstage, as well (more on that later).


At this price range, my biggest hope for the treble is that it’ll be unobtrusive, and that’s exactly how it is with the HD350BT. Never once did the treble come off as sibilant or harsh. It’s present enough to give a general sense of detail, but not enough to cause fatigue. Well done, Sennheiser!


And here it is, the biggest selling point of this headphone: it has a large, natural-sounding, airy soundstage with very good, natural positioning of instruments.

Now, this is a closed-back headphone, and audibly so; there’s some of the ringing that’s typical of your average closed-back headphone. As such, imaging can suffer a tiny bit, as expected. And I do get the idea that at least part of the soundstage’s width is due to a sort of artificial sense of distance created by the laid-back upper midrange.

Still, for this price, a Bluetooth headphone with a soundstage like this is an anomaly.

The HD350BT being held by me


Pros: sense of clarity, wide and involving soundstage, great value for price

Cons: could sound thin for some, somewhat lacking in dynamics


While the HD350BT won’t appeal to those looking to blast pop music, nor those looking for a headphone with a warm, meaty, or intimate sound, it very much appeals to me. I wouldn’t encourage you to buy it completely blind, especially when it comes to fit, but if you’re looking for a wide soundstage and an airy, clear sound signature, the HD350BT is the pair to get. For $120, it can’t be beat.

Find the HD350BT on Audio46 or Amazon.

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Evan - that is to say, I am a composer of music that could be described as sad and fragile, or so weird as to be offputting, depending on who's asking. I've been excited about headphones for years now. Need to get in touch? Email!