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Home Cinema sound for Your PC!

A good sound card is definitely a critical factor for serious gaming or for listening to music on a PC. But it's not everything! It's much better to add a good 4.1 or 5.1 sound system if you need power and quality. The best sound card in the world will not be much good if it doesn't have adequate speakers to match. And don't forget the quality/price ratio. In the end, all these factors make it hard to find the optimal solution.

Similar to graphics, sound has become a factor of major importance in the PC world. PC users who are avid gamers, collect MP3s or watch DVDs need a good sound card and an equally good sound system. The arrival of Klipsch and Videologic on the high power and sound quality scene has opened a significant breach that other more well-known manufacturers have rushed into without looking back. Let's not forget the undeniable contribution of Creative Labs and Altec Lansing who imposed the 4.2 and 5.1 sound standards for games. And it is indeed undeniable that PC sound has made enormous progress. Nowadays, we would never consider doing without all the latest developments that immerse us into the gaming world as never before.

Selection criteria

No benchmark could ever provide a definitive evaluation system for surround sound. So in the end it is up to your ears to be the final judge. The trouble is that the perception of sound and its quality is far too subjective to allow someone else to decide in your stead. Still, there are one or two important, standard factors that help you ascertain whether a system sounds good or not.


The quality of high, medium and low frequencies:

The high frequencies must be crystal clear and, above all, not saturated, even at the highest volume. Medium frequencies must be quite discernible, not muffled, and the low ones deep and percussive. So you should avoid any subwoofers that are so muted the sound comes out as a mush, devoid of any acoustic detail. Then there's the balance. The high frequencies shouldn't crowd out the low ones and vice versa. To improve this, you can always use the settings provided, that is, if they are actually provided. And be careful of the power ratio between the subwoofer and the speakers, which should not be to too high or too low. A good range is from one/two to one/four.

Separation:

Instruments should be well separated for music listening. You should be able to distinguish all the sounds clearly and tell the difference immediately between, say, a double bass and a viola. This is where crossover comes into its own - it is the meeting point of frequencies from the subwoofer and the speakers. If it is too low, a bass sound is likely to come out of the subwoofer and the speakers at the same time, or out of the speakers alone, which is not good for quality sound reproduction.

Power:

A flood of watts is not necessarily what music lovers need most. So don't be overwhelmed by the figures the manufacturers announce. Power should be given in RMS watts (Root Mean Square) and you have to take account of the ratio between diaphragm size and the number of watts. Generally speaking, at least for multimedia systems, the bigger the speaker, the more power it needs. This is not necessarily true for hi-fi, which sometimes uses very big, powerful drivers (at the back of the speaker), powering less than ten watts.

Connections:

As with sound cards, the quality and format of a system's inputs are decisive factors for its use and performance. A 2 or 3.1 system can be quite happy with a single mini-jack stereo input and a headphone output, whereas a 4.1 system, and even more so a 5.1, should have a range of several analog and digital connections. An AC-3 decoder for instance, must have an S/PDIF input in RCA or Toslink format. Users will obviously be very happy if there are both. Other major points are the controls, which should be as numerous and accurate as possible, element shields, overall size and ergonomics of the system and, of course, the design.

Dolby Digital Sound

In 1965, an American physicist and engineer named Ray Dolby founded the Dolby labs in London. His idea was to develop noise reduction systems to improve sound quality for professionals and the general public alike. The Dolby name is now known throughout the world, and the surround sound standards he created are used both in movie theaters and at home. Here's a brief reminder of the two predecessors of the Dolby Digital flagship standard:

Dolby Surround:

this has three channels, two for the front and one for the rear, with a bandwidth of 100 Hz to 7 kHz.

Dolby Pro Logic:

this is an enhancement of Dolby Surround with four channels, including a center channel and two elements sharing a channel for the rear sound.

Dolby Digital 5.1,

also called AC-3 (for Audio Code-3), has six channels - two front, two rear, one center and one for the subwoofer. Unlike Dolby Surround and Prologic, the bandwidth here ranges from 20 Hz to 20 kHz. The "5.1" refers to the five front and rear parts, plus the subwoofer, called LFE (for Low Frequency Effects), represented by the "1". The term AC-3 refers to a coding technology which eliminates sound data the user cannot hear and produces a Dolby Digital sound band coded on six channels. An absolute prerequisite for Dolby Digital sound is a decoder, such as the one on the Creative Labs Inspire 5700, or else a sound card like Audigy or Acoustic Edge, which decodes 5.1 sound and has the correct outputs.

There are also systems with just two speakers and a subwoofer which use Virtual Dolby Digital. These use a front channel mixing process to produce a virtual center channel; the rear channels are emulated by a processor which "virtualizes" surround sound using the HRTF filters via the front speakers.

Dolby Digital uses a fixed sound compression method of about 1:2. In other words, however much sound there is to encode, the compression will always be the same, because the compression algorithm has a constant output. Beyond this, there is a simultaneously positive (disk space) and negative aspect - negative because sound quality decreases as volume increases. But set against this is that the less space used on a DVD, the more space is available for different languages or bonuses, and this can compensate for a loss of quality. In general, AC-3 sound is coded in 18 bits, so the standard output of an AC-3 flow is 384 Kbps (6 channels x 18 x 48 kHz). On restitution, the Dolby Digital decoder transmits with a delay of one millisecond on the front channels because the listening position is usually closer to the rear speakers than the front or center ones. This optimizes simultaneous sound reception. With some decoders you can adjust this delay to get the best listening configuration.

The main advantage of this standard is the fact that it is the digital audio surround standard for DVD. In the rules defining the DVD standard, no other kind of digital sound band can be inserted on a DVD unless there is also a Dolby Digital-encoded sound band. So you'll never find a DTS sound band on its own. This leads to the second advantage of the standard - it is virtually universal. The first movie with a Dolby Digital 5.1 sound band was "Batman Returns" in 1992. Since then, practically all DVDs have perpetuated the standard.


For 3d Solutions range of Computer Cinema sound products visit the products page and look at sound cards and speakers.

         

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