14 DAY TRIAL // When it comes to games, you definitely have to own a cool graphics card. But present-day games are not just breathtaking visuals, they are about surround and 3D sounds, not to mention an extraordinary soundtrack. Well, in order to get immersed and really live those cool games, you really need a good sound card. With a serious sound card, your music and films will sound great, too. It's true, you need a sound system in addition, but we'll deal with speakers later. This article is dedicated to the history and the features of sound cards.
Sounds like fun
A sound card is a computer expansion card that can input and output sound under control of computer software. Typical uses of sound cards include providing the audio component for multimedia applications such as music composition, editing video or audio, presentation/education, and last but not least, games. Many motherboards have integrated sound capabilities, but these usually target mainstream users. Serious musicians and gamer enthusiasts require high definition sound cards to complement their expensive sound systems.
Naked sounds
Nowadays, a typical sound card would include a series of components that ensure the stability of sound processing.
- The Digital Signal Processor (DSP). Just like a graphics processing unit (GPU), a DSP is a specialized microprocessor that takes some of the workload off from the computer's CPU by performing calculations for analog and digital conversion. Current DSPs can process multiple sounds, or channels, simultaneously. More advanced designs usually include more than one DSP to separate duties between digital sound production and synthesized sounds (usually for real-time generation of music and sound effects utilizing little data and CPU time).
- The DAC & ADC (digital-to-analog & analog-to-digital converters), which converts recorded or generated digital waveforms of sound into an analog format. Sounds and computer data are fundamentally different. Sounds are analog - they are made of waves that travel through matter. People hear sounds when these waves physically vibrate their eardrums. Computers, however, communicate digitally, using electrical impulses that represent 0s and 1s. Like a graphics card, a sound card translates between a computer's digital information and the outside world's analog information through the DAC and ADC. Many new sound cards use a coder/decoder chip, also called a CODEC, which performs both DAC and ADC functions.
Multi-channel DACs, able to play multiple digital samples at different pitches and volumes, can optionally apply real-time effects like filtering or distortion. Multi-channel digital sound playback can also be used for music synthesis if used with a digitized instrument bank of some sort, typically a small amount of ROM or Flash memory containing samples corresponding to the standard MIDI instruments.
- Memory - as with a graphics card, a sound card can use its own memory to provide faster data processing.
- Most sound cards have a LINE-IN connector where the sound signal from a cassette tape recorder, older pick-up or similar sound source can be input. The sound card can digitize this signal and store it (controlled by the corresponding computer software) on the computer's hard disk for editing or further reproduction. Another typical external connector is the microphone connector, for connecting to a microphone or other input device that generates a relatively lower voltage than the LINE-IN connector. Input through a microphone jack is typically used by speech recognition software or Voice over IP applications.
- Input and Output Connections - some sound cards include so many input and output connections that they have a breakout box, which often mounts in one of the drive bays, to house them. These connections would include: * Multiple speaker connections for 3-D and surround sound. * Sony/Philips Digital Interface (S/PDIF), a file transfer protocol for audio data. It uses either coaxial or optical connections for input to and output from the sound card. * Musical Instrument Digital Interface (MIDI), used to connect synthesizers or other electronic instruments to their computers. * FireWire and USB connections which connect digital audio or video recorders to the sound card.
Cybersound - The Beginning
The early PCs knew nothing about high definition sound. Back then, a PC could produce only one sound at a time. Nay, not even a sound. It was more like a beep. The PC speaker was limited to square wave production, leading to the common nickname of "beeper" and the resulting sound described as "beeps and boops." The computer was familiar with the changing of the beep's frequency and duration, but didn't know how to influence the overall volume or how to produce other kinds of sounds.
At first, the beep acted primarily as a signal or a warning ( reminiscences of these beeps can still be found in today's motherboards, at system start-up). Later on, game developers created music for the early PC games using beeps of different pitches and lengths. This music was quite primitive, with no clear difference between instruments.
The 1980s proved to be the foundation for most of today's technologies and computer sound generation makes no exception. Manufacturers realized that more realistic sounds could contribute to the gaming experience and decided to introduce add-on cards dedicated to advanced sound control. Now, a computer with a sound card can do far more than just beep.
Thanks to those generous visionaries, our computer can produce 3D audio for games or surround sound playback for DVDs. It can also capture and record sound from external sources.
The first IBM PC was quite at a loss when it came to multimedia applications like music composition and gaming, while other home computers such as Amiga or Commodore were already offering hardware support for digital sound playback and sound synthesis.
In 1983, models such as IBM PC Junior tried to compensate for that loss. Using a Texas Instruments chip, it was possible for the machines to pass 3 sound channels and one noise channel with 16 volumes each. Pretty impressive for that time.
Around the same date, a company called Tandy introduced the TL/SL model which was capable of direct playback of digitized samples with simultaneous utilization of the synthesizer.
Covox figured out that the parallel port on the motherboard can be used in conjunction with some sort of sound hardware. The early parallel port was able to pass out 8 bits of information simultaneously which could be easily converted into electric oscillations. Thus, in 1986, Covox introduced the "Speech Thing" sound card - a simplistic card that featured a bunch of resistors and a primitive looking DAC (digital to analog converter). Some other versions even supported recording capabilities and there were circuits which made stereo playback possible using a switching circuit with two DACs.
In 1987, AdLib Company started implementing the Yamaha YM3812 sound chip (today commonly known as OPL2) in its sound cards. The chip featured 6 voices plus an additional 5 for drum instruments. The included set of voices and instruments was completely programmable and the user could, with some skill, reproduce real life musical instruments. Nonetheless, game developers didn't make the most out of these capabilities for their games.
Meanwhile, IBM and Yamaha came up with a Music Feature Card. This card featured the Yamaha FB-01 sound module which supported 8 frequency modulated voices, stereo-panning, and each voice was controlled by four operators instead of two (AdLib's standard). The card had an outstanding built-in library of over 300 high-quality synthesized instrument. Users were able to put two of these cards in a single machine and get 16 voices. However, the sound card was very expensive for that time - $600.
Creative Music Systems (now known as Creative Labs) made its big move in 1988 with the introduction of the "Game Blaster." The sound card was basically made of 12 PC speakers put together and included a volume alteration of 16 steps, a noise generator that reproduced 3 different drum sets and, above all, it supported stereo playback. Creative Labs struck deals with many game developers and soon, many games natively supported the Game Blaster and the forthcoming legacy products.
The same year, Roland launched the legendary LAPC-1 sound card which offered 32 MIDI channels (however not simultaneously), with 12 bits D/A, 32 Khz mixing and reverb effects. Moreover, there was a library of 128 pre-defined instruments and users could load their own instruments via patches. It cost approximately $500 and it was intended for professional music artists rather than gamers, although it sounded excellent in games, too.
With the Roland supremacy, Creative Labs quickly realized that their Game Blaster was sentenced to sudden death. The support was not outstanding, and most of the game developers did not even use the included effect channels. Creative finally understood that their sound cards should know how to handle samples. Thus, version 1.0 of the venerable Sound Blaster integrated a DSP that delivered a sound quality of 22 Khz 8 bits Mono and recorded with at 13 Khz. Creative, helped by Microsoft, managed to persuade Yamaha to make its OPL2 chip available for the entire market, not only for AdLib. With this move, Creative rapidly produced cheaper sound cards and offered programming support for them, leaving AdLib in a huge cloud of dust. The first Sound Blaster versions had their problems, no doubt about it, but they really brought the playback of digital samples close to end users.
Sound Blaster 2.01 further improved things, making sound playback with 44, 1 Khz sampling rates possible. This improvement brought several changes to the DSP interface and it is because of this that the game developers and software programmers started to encounter difficulties.
Regarding game integration, the first game company that opted to support add-on music hardware was Sierra On-Line. Two of the companies Sierra partnered with were Roland and Adlib, opting to produce in-game music for King's Quest 4 that supported the Roland LAPC-1 and Adlib Music Synthesizer. The LAPC-1 had superior output quality, due in part to its method of sound synthesis as well as built-in reverb. Being the most sophisticated synthesizer they supported, Sierra chose to use most of the LAPC-1's custom features and unconventional instrument patches to produce background sound effects (birds chirping, horses clopping, etc.) before the Sound Blaster brought real audio playback clips to the PC entertainment world. Many game companies would write for the LAPC-1, but support the Adlib as an alternative due to the latter's higher market base. The adoption of the LAPC-1 led the way for the creation of the MPU-401/Roland Sound Canvas and General MIDI standards as the most common means of playing in-game music until the mid-1990s.
Creative is the most important player on today's general consumer sound card market. Sound cards that followed the original Sound Blaster family include: Sound Blaster Pro, Sound Blaster AWE32&64, Sound Blaster Live!, and the Audigy line-up. However, around 1998-1999, a company named Aureal managed to steal Creative's shine with its 3D sound technology - A3D. Nonetheless, on September 21st, 2000, Creative acquired Aureal's assets from its bankruptcy trustee for US$ 32 million, and Creative reclaimed its position once again. There were/are many other sound card manufacturers besides Creative: Gravis, Turtle Beach, TerraTec, M-Audio, Realtek (for integrated sound solutions only) etc, but they aren't as respected as Creative.
Analog vs. Digital
The ADC translates the analog waves of your voice into digital data that the computer can understand. To do this, it samples, or digitizes the sound by taking precise measurements of the wave at frequent intervals. An analog-to-digital converter measures sound waves at frequent intervals. The number of measurements per second, called the sampling rate, is measured in kHz. The faster a card's sampling rate, the more accurate its reconstructed wave is.
If you were to play something you recorded back through the speaker system, the DAC would perform the same basic steps in reverse. With accurate measurements and a fast sampling rate, the restored analog signal can be nearly identical to the original sound wave.
Even high sampling rates, however, cause some reduction in sound quality. The physical process of moving sound through wires can also cause distortion. Manufacturers use two measurements to describe this reduction in sound quality:
* Total Harmonic Distortion (THD), expressed as a percentage. * Signal to Noise Ratio (SNR), measured in decibels.
For both THD and SNR, smaller values indicate better quality. Some cards also support digital input, allowing people to store digital recordings without converting them into an analog format.
3-D and Surround Sound, the X-Fi revolution and Sound APIs
Game designers use 3-D sound to provide fast-paced, dynamic sound that changes based on a player's position in the game. In addition to using sound from different directions, this technology allows realistic recreations of sound traveling around or through obstacles. Surround sound also uses sound from several directions, but the sound does not change based on the listener's actions. Surround sound is common in home theater systems.
One of the newest advances in sound card technology is X-Fi, or Xtreme Fidelity, from SoundBlaster manufacturer Creative. X-Fi's most notable features include:
* Active Modal Architecture, which gives people different sound options for games, leisure use or music creation. * A Digital Signal Processor (DSP) with 51 million transistors. * Multiple processing engines, each of which performs specific sound operations. * A 24-bit Crystallizer, which reverses some of the sound quality loss inherent in 16-bit CD recording. * 64 MB on-board memory.
Like a graphics card, a sound card uses software to help it communicate with applications and with the rest of the computer. This software includes the card's drivers, which allow the card to communicate with the operating system. It also includes application program interfaces (APIs), which are sets of rules or standards that make it easier for software to communicate with the card. The most common APIs are:
* Microsoft: DirectSound * Creative: Environmental Audio Extensions (EAX) and Open AL * Sensaura: MacroFX * QSound Labs: Qsound
You can't really evaluate an excellent sound card without a serious sound system. The next article will focus on the speaker and home cinema systems. Be sure to check it out tomorrow.