Why you can trust TechRadar
We haven't talked much about the Sennheiser PC-350s yet, and with or without the Xonar card in tow, they're an astoundingly good set of cans.
Everyone has their own particular preferences when it comes to reviewing audio gear, but to our ears the balanced tone of the Sennheisers – which don't overplay the bass, and leave high frequencies crystal clear – can make any old on-board sound chip sound like you're sitting in the Royal Albert Hall.
If you prefer something with more of a big bass punch, however, then you're clearly better off choosing your own scalp-clamping sound boxes.
The bigger issue is that the breakout cable for speakers feels slightly inelegant, and may need another adaptor if your speakers don't have 3.5mm inputs. It doesn't quite feel in keeping with the quality of the headphone channel, and makes the whole package slightly inflexible.
Anyone who wants to hook up an external amp will prefer the RCA connectors of the Creative X-Fi Titanium HD or Asus' similar Xonar Essence STX, which also has an excellent on-board headphone amp.
Both high-end Xonars can match the impedance output of the amp with the input requirement of the headphones too. You can dial down the power from 600ohms to 150ohms in the driver settings to match the PC-350's requirements.
Just make sure you do that before plugging them in or you could blow out the speakers.
The overall soundscape produced by the card and cans, though, is warm, rich and with an excellent dynamic range that's a fair rival for a much more expensive stack of audio separates.
It benchmarks better in Rightmark's Audio Analyzer than Creative's ostensibly superior X-Fi Titanium HD, and is great for gaming, with easily located positional effects, and the clarity to hear voice chatter above background explosions.
The Xonar driver suite is also easy to set-up and configure, with equalisation presets for different games, films or spatial settings.
As with any sound card review it's very easy to point out that similar quality which is almost indistinguishable to the casual gamer is available for less elsewhere, and there's a small stack of perfectly serviceable options ranging from the £40-odd Xonar D1 or Creative X-Fi Xtreme Gamer.
It's hard to fault the Xense on the value-for-money front, though, since bought separately, the total price of the headset and sound card would be around £260.
So if you want an excellent quality set-up and don't mind the diminishing returns over a much cheaper sound card and headset combo, the Xonar Xense is actually the most sensible way to get into high quality headphone hi-fi for gamers and music buffs alike.
By adding in one of TechRadar's favourite gaming headsets that almost comes close to studio quality sound, the Xonar Xense dodges the value-for-money bullet which makes it so hard to recommend high end PC audio gear to anyone but the most fanatical phonic fan.
The sound card itself is truly excellent, matching Asus and Creative's best.
By emphasising on the headphone use, the card is slightly crippled elsewhere. It just seems unlikely that anyone spending £200 on audio kit is going to accept the dodgy dongle and 3.5mm jacks for everything else.
Essentially a £160 sound card for £100. If you haven't got a high end set of headphones, it's a good way to buy into hi-fi audio.
Follow TechRadar Reviews on Twitter: http://twitter.com/techradarreview
Dan (Twitter, Google+) is TechRadar's Former Deputy Editor and is now in charge at our sister site T3.com. Covering all things computing, internet and mobile he's a seasoned regular at major tech shows such as CES, IFA and Mobile World Congress. Dan has also been a tech expert for many outlets including BBC Radio 4, 5Live and the World Service, The Sun and ITV News.
'Virtually unhackable' chip could make GPU more power efficient and much faster at AI - by combining light and silicon for a fundamental mathematical operation
Can Constellation break another Apple TV Plus record? Here are 5 more sci-fi smash hits to stream
Sennheiser upgrades its Accentum model while still undercutting high-end options