Sennheiser's PC163D headset only packs two speakers, so you are only getting the illusion of surround sound.
However if the audio processor can convince your brain that in-game sounds are coming from in front of you or behind you, instead of just from the left or the right, then what’s the difference?
For almost a year now I’ve been using a headphone amplifier with a built-in Dolby Headphone processor so I have had a fair chance to evaluate this technology. At first I refused to use it, as the resulting sound is somewhat muffled, as if you have put a bucket over your head. However the heightened ability to pinpoint where sounds are coming from in-game eventually prevailed, and I'm now a die-hard believer. The accepted terminology for this is “sound whore”.
Couple this technology with a decent midrange pair of Sennheiser cans and you have a winner. The PC163D headset appears identical to the Sennheiser PC166 headset which retails for about NZD $60 less, so that’s about how much you are paying for the privilege of the Dolby Headphone processing.
As far as audio quality goes, this is the first sub-NZD $300 headset that I have personally used which manages bass correctly. Most headsets from Creative and Logitech have powerful bass but tend to drown out the midrange. This approach allows explosions to drown out voices, for example, whereas a lot of Steelseries and Microsoft headsets just don’t have enough bass in the first place.
I’m told that the Razer Carcharias also have good bass response and midrange separation – I’ve only used the Megalodon myself which was indeed excellent in this aspect, on par with the PC163D which is a solid effort considering the Sennheisers have smaller drivers.
Having a decent bass output with good midrange separation also makes the PC163D’s music performance enjoyable – however you wouldn’t use the surround sound capabilities for music, plus the non-removable boom microphone is a bit dorky to be wearing on the bus if you are after portable audio.
High frequencies are crisp and clear, which is typical of Sennheiser headsets. There's very little fatigue even after a couple of hours of reasonably high-volume gaming (granted, the surround sound processing muffles the high frequencies a little bit).
To enable the surround sound processing, you need to install the supplied drivers, or preferably the latest drivers from the Sennheiser website. After doing this, you go into Audio properties in Window's Control Panel, and set your audio configuration to 7.1 Surround. This will send full 7.1 channel audio, where available, to the USB sound card, which will in turn "smoosh" it into a two-speaker surround sound arrangement.
If you are going to use this headset for music, I highly recommend enabling the 'Loud' option which you will find on the Advanced Controls tab of Window's Volume Control. This will boost low and high frequencies at low to mid-volumes for a sweeter, bassier sound (much like setting a V-shaped graphic equalisation).
The noise cancelling microphone is also top-notch, being noticeably clearer than my Steelseries 7H microphone. The boom arm however is a bit annoying – I’m not sure if it is just the unit I received or whether they are all like this, however it kept slipping down away from my mouth during use, as if there wasn’t enough tension in the swivel mechanism. I shoved a small bit of paper into the mechanism to stop this from happening, but that is still bad form for Sennheiser.
Physically the PC163D is ultra-lightweight; you do actually forget you are wearing them after a while. The design is supra-aural, i.e. the pads sit on your ears, rather than around them, and they are open-backed, meaning sound can leak both into and out of the headset. Ostensibly this is so you can talk to your teammates during a LAN session, however any serious gamer tends to use a voice-chat program in the first place. Personally I would have preferred a closed-back design to block external noise, but this can also lead to sweaty ears during long gaming sessions, so it is a trade-off either way.
After using the PC163D for long hours over a couple of weeks, I would happily promote it to my main pair of cans. As a stereo headset they have great soundstaging, bass response and midrange separation – everything you need for a good gaming experience – and coupled with the Dolby Headphone processor the surround sound effect gives you an extra advantage on the battlefield.
From the range of headsets which come with a Dolby Headphone amplifier such as the Astro A40 system, Tritton AX720, Turtle Beach X41 and Logitech G35, the Sennheisers are actually one of the cheapest available. The PC163D doesn't have amplified volume control or wireless functionality like some of these systems however.
If you are after a surround sound headset to take to LANs I would consider the closed-back circum-aural PC333D instead, other than that I honestly wouldn’t hesitate in recommending the Sennheiser PC163D to any serious or casual gamer.