Winter Audio Reference: On-Board, Consumer, and Pro Solutions

The Anatomy of a Sound Review (User Experience)

The factors included in an end user experience are much more straight-forward than the technical electrical performance of audio hardware. Of course, they are highly interconnected. The listening experience and quality of audio recorded by hardware is a direct result of the electrical capabilities of the hardware as discussed in the previous section. Talking about listening on a qualitative level is very difficult, especially when trying to give others good advice about what to buy. We can sit here and say that: if a device with one set of numbers (dynamic range, THD, etc.) is played on $50000 speakers, it will sound different than a card with worse numbers. What we can't say is how great this difference will be (because the speakers will still likely introduce more distortion).

Random PC speakers are not going to show many differences unless a sound card is essentially broken.

Again, it's difficult to listen to hardware and know what you're hearing. Our approach was to listen to a track over and over and over on one device and then immediately switch to another in order to listen for differences. If there are any, we try to determine what they sounded like, and why they are there.

For high quality audio testing, we used Sony MDR-7509 studio monitors (open air headsets were evaluated, but since we're testing near computers, and henceforth noise, isolation was desirable). For surround and gaming testing, we used Logitech Z-5300 speakers.

This brings us past audio quality and into something that AnandTech readers will be familiar with: performance. We tested how many direct sound channels that we can run (and at what CPU overhead). We will also look at how much of a performance hit it is to enable audio in Unreal Tournament 2004. We had run numbers for Doom 3 as well, but the fact is that there just isn't a performance difference - these newer games are simply too bound in other areas to exhibit any performance difference on different audio cards.

We also need to look at audio API support. As Creative is the mover and shaker in the industry, they bully most companies into using their EAX for audio in some way or another. For example, they forced Id to incorporate EAX into Doom 3 by leveraging John's "Carmack's Reverse" shadowing algorithm against him - Creative holds the patent on depth fail stencil shadows through 3DLabs. Then there's Sensaura, which Creative now also owns. The latest versions of Sensaura include support for EAX 2.0. In our look at Unreal Tournament 2004, we will see performance under software 3D, hardware 3D using OpenAL, and hardware 3D + EAX.

We like the idea that Id has in playing audio straight to surround channels through DirectX. You get better results than using DS3D (or any other 2 channel) positional audio and it's more accurate than upmixing using features like Creative's CMSS 3D. When actually creating true surround sound, the developer has full control, and since Id did it with no performance hit, there's obviously more than enough CPU power to go around these days for doling out audio. Of course, in implementing audio this way, the game developer must give up the comfort of the built APIs and the HRTF (head related transfer functions) that they implement, and build a sound engine to keep track of everything themselves. The major problem of implementing real positional sound then becomes lack of convenience rather than lack of hardware power.