What is... a sound card?
The apprehension of previous screen serves to us to introduce this new point. Was Porqué called SoundBlaster AWE 32? It was not for the bits with which it was working, as we have already said earlier, but for 32 simultaneous voices (instruments) that it was capable of reproducing. (Also the same happens with the SoundBlaster 64 and 128, as well as with the MaxiSound 64).
This concept is not complicated. With a Jazz quartet really exceptional works can be interpreted, of course, only with 4 instruments. If the group increases 8 persons, we will be able to have the instruments double and the sound will be much better. At present we can find sound cards with support of 320 voices of Diamond Monster Sound, happening for 256 voices of SoundBlaster Live!, the 128 of the SoundBlaster PCI 128, or the 64 of the Guillemot ISIS or Home Studio Pro 64. Thanks to the use of the connector PCI cards have obtained with many voices nearly money, since they use the memory of the PC to store them, but the computer will have to be powerful to obtain a satisfactory yield.
You can do to yourselves an idea of the quality of the music that it is possible to obtain on having composed with such a number of voices. Of course, the number of voices will be the number of instruments MIDI that we will be able to reproduce in the same time moment. If we reproduce a CD or a.wav, the number of voices will not influence us in the reproduction quality. In this case we leave the MIDI aside, we will be speaking about music recorded in digital format, and will have to refer to channels.
Well, we have a heap of possible voices that we will be able to treat. In the most advanced solutions we have possibilities of doing our first pinitos in the music.
When we treat with one of the sound tracks that we have engraved, for example, we have (in many cases) the possibility of applying effects to him, as there are the "chorus" or the reverberation. But also to simulate sound synthesizers, to realize "fades"...
Of course, this process of modification of a digital sign needs calculation potency, but normally it is desirable to know how it will affect the application of an effect in real-time. It is for it that many solutions, especially from the average scale, incorporate a Digital Processor of Signs (DSP: Digitalis Signal Processor) to liberate of work to the microprocessor of the PC; one of most used at present is the EMU10K1.
Channels, loudspeakers and the fever 3D
We might explain the concept of channel or track of simple form like a track of different sound for every loudspeaker in which there will be recorded the information that it must reproduce, so that information of other loudspeakers does not come to him. This way every loudspeaker will reproduce the sound that corresponds to him, achieving the wished realism.
When the "revolutionist" of that time ADLIB appeared, it was capable of reproducing the sound for 1 channel, or, we speak about sound monoaural in his most strict sense. When we listen to the sound stereo, it comes to us by means of 2 channels, the lefthander and the right, improving very much the realism of the sound.
But there came a moment in which this seemed to be small, and the fever came untied 3D: what does the sound placed in front of us? Would not it be better that it was surrounding us? Since this Dolby Surround is going to try to reproduce, AC-3, A3D, THX, DirectSound3D... To produce surrounding sound multitude of systems exists:
Some sound cards say to be capable of producing sound 3D with only 2 loudspeakers (I have one of those, which costs 2500 ptas., you can do to yourselves an idea of the reality of the affirmation). These systems, more than surrounding sound, believe "strange sound", since they combine 2 channels of the stereo to provoke depth sensation in sound (never "surrounding" sound).
lately, in addition to 2 traditional loudspeakers, the sellers offer a Subwoofer (also known like loudspeaker - enorme-que-no-sé-dónde-colocar). This loudspeaker is used principally for the reproduction of the most serious sounds, but we will keep on having only 2 channels.
Others use 4 loudspeakers, in sound cards cuadrofónicas. These have 2 exits stereo, for 2 pairs of loudspeakers (a whole of 4). The obtained quality is quite good, since, in addition to 4 loudspeakers that do that we perceive the sound from any direction, the most modern cards incorporate software that allows the calibration of our position with regard to the loudspeakers, fitting automatically the volume so that the sound "centers" on our head (although it sounds very complicated, the truth is that it performs the simplest thing: if a loudspeaker is further of us that other and for the 2 we express the same volume, we will notice the displaced sound, the challenge will be to fit the volume of every loudspeaker to listen to the sound as centered as possible).
More advanced systems, they reach port as it happened with the systems of 2 loudspeakers, a subwoofer together with 4 loudspeakers, obtaining a major realism in the surrounding sound. There exist already diverse solutions (like the Creative FPS 2000) that for an economic price provide quadraphonic sound with four loudspeakers and a subwoofer.
Sound specifications 3D
We have already spoken a little about the sound 3D, nevertheless we have earring answering the question of how it is obtained. We are going to answer it: in the same way that games exist with graphs 3D, also they can support sound 3D (or environmental). If a game 3D must be programmed by some graphic bookstore 3D (Glide, Direct be read 3D or OpenGL), also it it must be to support the environmental sound, by means of the use of some of the existing formats.
The most well-known are Direct Sound, Direct Sound 3D (from DirectX 6), Aureal A3D 1.0 or 2.0, Dolby Surround Prologic or Dolby Digital.
Each one has his advantages and disadvantages. Direct Sound 3D is much used in games in environments Windows, for what his support is almost essential to be able to enjoy the best qualifications of last generation in all his splendor. Aureal A3D has been a proprietary API that in the beginning was used because Direct Sound was not supporting environmental sound quite well that should, nevertheless, with new Direct Sound 3D, it should not be necessary.
Separate mention is deserved by the specifications Dolby Surround Prologic and Dolby Digital, direct competition of the THX of the multimillionaire George Lucas. With the appearance of the DVD the entertainment sector has been revolutionized.
When in our computer we have a breeding animal DVD, we will be able, theoretically, to enjoy the video qualifications in this format. But if really we want to enjoy thoroughly them, 2 things will be necessary. First, a card decodificadora of MPEG2, because with only our CPU the quality that we will obtain will not be the ideal one; and on the other hand, a sound system that support Dolby Digital, and in it we include the sound card, which must offer this support, and the loudspeakers, which must be the necessary ones.
Digital Dolby or the movies at home
Straight imported from the movies, so you can do an idea of the quality to yourselves.
The excellent format of the DVD is Dolby Digital 5.1 or AC3. This format is a direct evolution of Dolby Surround Prologic, it uses 6 tracks, therefore 6 loudspeakers will be necessary: 1 head office, 1 lefthander and 1 right, 1 left loudspeaker and right 1 for the sound ambience (behind the spectator) and 1 subwoofer to heighten the serious ones.
Also there will be necessary an amplifier that supports this sound format, in addition to our card. A good example is Creative Desktop Theater 5.1 in conjunction with a SoundBlaster Live!.