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In the Forums... |
Posted: April 10, 2000 Written by: Tuan "Solace" Nguyen Q3D  Q3D is from the creators of QSound. Q3D2.0 is an acceleration layer on top of DS3D. It is efficient and supports EAX1.0 in software. Q3D is also able to virtualize Dolby Digital, emulating the center channel with the front left and right speakers. Currently, Q3D employs HRTFs when you choose to use headphones and Q3D and panning similar to A3D when using speakers. An interesting technology from QSound is its Q123, which expands monophonic signals. The effect attempts to sparse certain frequencies to your left and right speakers, simulating stereo. The actual effect causes the sound imagery to appear confusing. At times, certain sounds like a drum beat would suddenly switch speakers. The original mono sound itself may even sound better unfiltered. Expanded Stereo, Surround Sound, and Positional 3D Audio are all methods of enhancing sound, making it more realistic. Expanded Stereo would be the least expensive of the three and Surround Sound being the most because of receivers and speaker setups. Of those two, none offer interactivity with the listener and are usually all predefined. In some early games that offered options better than Stereo, Dolby Pro Logic was used, but that method died out because it was uneconomical for the player. So where is EAX and I3DL2? Reverbaration Reverb is a method of layering echoes to a sound to make it seem like it is playing in a certain environment. Speaking in a small bedroom sounds much different than speaking in a large hall. The sounds travel further and take longer to bounce back and causes echoes. In a small room where the walls are made of dry wall, the sound would be absorbed more and less sound would return to the source than if they were radiating in a hall with concrete walls. Reverb takes into account the size of the closure of the environment, whether it is in open space or in a closed space. Another factor is material. Speaking in a room with foamed walls sound much different from a room with wooden walls. These specific echoes help our brains identify the environment that we are situated in. It does not help clue where the sound is actually coming from. Reverb is a method of changing sound stage and sound environment. It does not use any HRTFs and panning techniques. EAX  Creative introduced Environmental Audio Extensions well over a year ago and it’s still doing very well and gaining leverage everyday. You may have known that already, but what you may not know is that EAX is not a 3D API. It doesn’t take sound to a place it in 3D space. It has no idea where sounds are coming from and may never will. But what it does know, it knows well. Simply put, EAX is a series of reverb techniques. It simulates sound in different environments. With it, you can tell the difference between a sound inside a metal pipe or a sound inside a stadium. You may say “but everyone says EAX does 3D sound!” And they are partially correct. EAX sits on top of DS3D and modifies the 3D streams and filters the streams through its standard 26 presets from small room to sewer pipe to stadium. Then, the amount of reverb is applied to simulate distance in objects. So, using DS3D as its Positional 3D Audio backbone, it can then further enhance the impressive sense of the environment. While Aureal had advanced effects like reflections and occlusions, EAX was just 26 reverb presets. Meet EAX2.0, Creative Labs’ answer to Aureal. EAX2.0 now includes support for reflections and occlusions. And also new to the table is early reflections, which are the echoes that precede real-world reverb. This gives a better simulation of environmental sizes and location of the sound source. As of April, 2000, Creative was working on EAX3.0, which will bring reverb-morphing. It allows the reverb effect to change dynamically, gradually or quickly with the environment change. For example, the music playing from the stereo in your room changes slowly as you start to walk away from it, out of the room, and into the hall, and out into the kitchen. Another feature that is in the works is one-shot reflections used to simulate ricochet effects such as gunshots in a large room. |
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