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Copyright
© 2001 Cooler Xtreme. All Rights Reserved. |
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Cooler Xtreme : Audio / Sound : Klipsch ProMedia 4.1 |  |
| 33D Audio – Making it work
There are two aspects to 3D audio. First on multi-channel speaker systems the sound card drivers take the positional information delivered by DS3D or A3D and send that sound to the appropriate speaker. This first important aspect of positioning has nothing to do with virtualization and everything to do with placing sounds in the satellites. While it's true that bass (low) frequencies aren't very directional you can still hear where they come from far below the 200 to 250 Hz crossover point many multimedia systems. As such one factor that can impact the effectiveness of positioning sound effects is the effective crossover point of a speaker system. Right up to the point where low frequencies become truly non-directional the lower the frequency a satellite can reproduce, the more it will be able to accurately position. This is true whether it is a 2,4 or 5 satellite speaker system. When it comes to stereo and even multi-channel systems there is another very important aspect of great 3D audio and that is virtualization of sounds from places where there are no speakers. Effective 3D audio virtualization can trick your brain into perceiving sounds behind you, beside you or even above or below you. These effects are crucial for stereo systems and can also notably improve even the multi-channel speaker experience. This type of virtualization occurs in a number of ways depending on the device you are using but all will be doing some combination of frequency filtering, sound delays and other neat psycho-acoustic tricks. In general just like any other sound source, low distortion and good frequency response will improve the way we perceive these effects. Not only will it sound more like "real life", cleaner more neutral systems also won’t be introducing unwanted artifacts that can disrupt the real cues generated by the 3D audio engines. For most 3D audio engines the effectiveness of many of the cues depends on a technique called crosstalk cancellation. In the most simple terms crosstalk cancellation is signal processing designed to keep sound meant for just one ear from going to the wrong ear. Here what has the most effect on how well the 3D imaging works is how directional the speakers are particularly for the midrange frequencies on which it is generally most important to have effective crosstalk cancellation. Effective placement of the satellite is also quite important and is one thing completely within our control. Here you ideally want the satellites in front and even behind at head height or at least well directed to the ears with no obstructions. When it comes to directionality there are differences in the dispersion of high frequencies for systems with cone based tweeters relative to single driver systems but that’s not too important for the 3D audio cues. What’s more important is good directionality of the midrange frequencies. Unlike the home theater market where it's quite common to find rear speakers that are bipole and hence very non-directional or dipole and often configured to be less directional through their full frequency range, the typical PC speaker uses small satellites that are typically directional even for midrange. That’s not to say there is no variability as there are both cone based and flat panel designs that offer both increased and decreased directionality sometime just for the rear satellites and sometimes the whole system. |
| Deathmatch Gaming
The most extreme case is deathmatch gaming like Quake3 and Unreal Tournament where the mostly bass-heavy weapon sound effects completely dominate. You also have the optional soundtrack and some ambient sound effects but the action is intensive enough that most of the time it will be overshadowed by the weapon sound effects. It’s obvious that the bass response and how well it blends with the midrange will be the most significant aspect of the system. Something else that’s true is tight, quality, bass is not as important in games as it is in music. Gamers tend to lean more towards how loud the bass can go rather than how tight it is. One other point of interest is while positional audio can be of great benefit in these types of games the action can often times get so frantic that you end up with one big acoustic blur! Action, action-adventure, action-RPG action-simulation Here we are grouping games with less frantic or intensive action that for the most part have real-time interactive environments as you might gather from all the "action". More importantly in these types of games sound tends to have a crucial interactive role that goes well beyond just figuring out where the bad guys are. In our minds this captures games such as Unreal, Half-Life, Thief, Rainbow 6: Rogue Spear and System Shock 2, Deus Ex and any other game you can think of that puts you into that first or third person real time interactive environment. It’s in this category that you will find most if not all of the best advanced audio implementations to date Bass effects are still important but the midrange and high-end becomes more significant in the reproduction of many amazing ambient sound effects and complex musical soundtrack, just like in a movie! Here the satellites of the speaker systems playing a much greater role delivering the experience intended by the sound designer. Just how important the reproduction quality of the speakers turns out to be will of course depend on the quality of the ambient sound effects and music soundtracks. However, both those are generally getting better and better. Sports Most sports games like hockey, baseball and football action games are captured here. The range of sound effects in these games are somewhat less flexible in terms of variety than the other genres with the goal many times being to simulate a real game or stadium experience. In some cases the audio can be used to assist in game play but most often the positional and reverb abilities of the sound card are put to work in placing crowd noise and creating just the right ambiance. Real time and turn based simulations, adventure and turn based RPG games Even more so than for the genres list just above, the ambient effects and soundtracks will dominate the soundscape of these types of games but just as with sports they tend to be less crucial to the actual game play with even more emphasis on setting the mood. Here we are think of games like Sim City 2000, Myth II, Tzar: Burden of the Crown, RPG games such Baldur’s Gate II and even traditional adventure games such as realMyst. Racing and flight Racing and flight games are a slightly different story than the other genres since you have more a mix of low-end frequencies and lower midrange frequencies than what you get for just explosions and it’s these engine noises that are present through much of the games. In fact in many cases the noises in your own cockpit can dominate. Even so there is still room for positional audio to play a key role in locating your opponents and generally create a more responsive and interesting soundscape. Of course explosions and other assorted low frequency bangs often also play a big role, particularly in the world of flight simulations. Examples include Need For Speed: High Stakes, Nascar III and Crimson Skies. |
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