Cinema has changed our understanding of leisure forever. It takes between us over a century, since the Lumière brothers made ​​the first public screening in 1895 and since that time has almost gone from strength, halfway between the show, a format that we Georges Méliès, and form of artistic expression. Although the first movies were silent, the first systems that allowed sound to enjoy next to the images did not wait long.

In the early 20s of the last century were born as Photokinema sound technologies, Movietone and Vitaphone, three systems that strengthened the foundations of cinema as we know it today: as a visual and audible manifestation. Since then, the image and sound quality of the films has been improving, but the funny thing is that the technologies that have made ​​this progress have been lowering, largely thanks to economies of scale, to make possible the emergence of cinema in our own homes. Everything started.

TechnologyThe first steps in the analog world

As we have seen, we know the origin of the film very accurately. What created the Lumière brothers; Georges Méliès conceived it as a form of entertainment, and filmmakers such as Sergei Eisenstein, Fritz Lang, FW Murnau or Charles Chaplin, among others, was given the ultimate accolade. All this happened between 1895 and the decades of the 20s and 30s of last century. We know what happened, when and who was responsible. However, determining the time when the cinema was born at home is not that simple.

Probably the best approach is to think that its foundations the first put them really popular formats for home video, as the Betamax, the VHS or Video 2000. Before they arrived alternatives such as recorders Ampex VRX-1000 tapes, but the the condemned high price exclusively to the professional market. In any case, these three distribution systems and video recording for home environments were inspired precisely in the tapes that are used professionally in television.

The VHS and Betamax formats, created by JVC and Sony respectively, were born in Japan in the early 70s both had in common the use of plastic tapes (the sure many remember) inside which was wrapped in a thin ribbon it was possible to store the video and audio in analog and by small magnetic fields. Despite their similarity, the two systems had some significant differences favoring the Betamax, VHS to beat its higher image quality (but lost out in other sections). But what we are really interested in this post is sound, and none of these audio formats offered a high quality. At least at first.

The first sound standards of these tapes were able to reproduce frequencies ranging from 100 Hz to 10 kHz with a SNR of only 42 dB. Most people are able to hear sounds that move in the range of frequencies from 20 Hz to 20 kHz, so the sound of those early films left much to be desired. Fortunately, he was gradually improving thanks, for example, the introduction of technology Dolby B noise reduction, created by

Dolby Laboratories.

But the most important step forward came in the early 80s, when both formats managed to improve their sound, offering stereo audio with a frequency response of 20 Hz to 20 kHz, a signal / noise ratio of 70 dB (ideally it as large as possible) and a dynamic range of 90 dB. Those tapes finally started to sound good. Although the televisions of the time could not be compared to the movie screens, both the image quality and the sound of the VHS and Betamax tapes began to offer an inviting experience, although not truly cinematic.

In 1979, when the two Japanese formats were settled both in Japan and in the West, Philips and Grundig, two electronics companies more powerful European consumption at that time, they released their alternative to VHS and Betamax. Video 2000 This system also used a magnetic tapes that stored video and audio in analog format, but introduced some important improvements such as the ability to record videos longer duration or a more effective system of protection of the magnetic tape. And in regards to sound, their main contribution was the introduction of a technology capable of suppressing noise dynamically.

The performance of the three formats improved during its lifetime, but in the end, which at first seemed the least advantaged from a technical point of view, the VHS, it managed to win virtually worldwide, and had good health until, much later, he arrived on DVD, and with it, the real home theater.

A key source in digital

Before we discuss the DVD, a format we know perfectly all worth to briefly mention the two video distribution systems that paved the way little later followed the DVD: The Video CD and Laser Disc. The first would store up to 74 minutes of video in digital format, and was more reliable and durable than magnetic tapes used by the VHS, Betamax and Video 2000 format but the video coding algorithms of the time were not much and the images suffered from a terrible compression artifacts.

Interestingly, the Laser Disc predates the four formats we have “revisited” so far. David P. Gregg invented and James Russell in 1958, and the first usable standard was introduced in 1972 it was an analog video system (although the PWM information was stored in a format similar to those used today in the CD, DVD and Blu-ray Disc), but offering reliability, durability and image quality superior to magnetic tapes of the era. Furthermore, sounded great. The audio could be recorded in analog or digital format (even both at once), and even offered the same quality of sound from a CD to use a sampling rate of 44.1 kHz and a resolution of 16 bits.

At the end of his life even walked Laser Disc movies with Dolby Digital, DTS and Dolby Digital EX, the same audio encoding formats currently used by the DVD, and then we’ll talk. But I had a major problem: the player, movies and sound equipment that was necessary to use to enjoy at its best in Laser Disc movies were very expensive.

And finally, we come to the birth of the format that was at the time breaking into our homes home theater with ‘all law’: the DVD. . Came to market in 1995 and was the only one who got dethroned once and for all to VHS is a completely digital format; Digital video and digital sound. No offers high-definition images, but, like the Video CD, its predecessor, is immune to interference and “aging”, two of the major drawbacks of magnetic tape. But one of the reasons that users loved it this format was sound.

A mid-90s and had many cinemas multichannel sound systems. But let’s go a little further back. Stereo sound came to theaters in 1975, with the help of the Dolby Stereo technology, and multi-channel did not expect much more. At the end of the 70 were released in some cinemas multichannel versions of Superman and Apocalypse Now a prodigy at the time. However, as we have seen, the first serious attempt to transfer this experience to our homes came from the hand of the Laser Disc, but in its last throes.

The DVD appeared promising not only an image of higher quality than VHS and its rivals, but also multichannel sound similar to that we could enjoy the best cinemas. Of course, we had to enjoy ourselves with a decoder capable of processing digital audio stored on disk, in Dolby Digital 5.1 or DTS, and a team of five satellite speakers and a subwoofer. Some DVD players have built-in decoder, which included RCA outputs that allow us to transport the decoded sound in analog format to a preamplifier, which could be a hi-fi system with multichannel input. But the other option was to get hold of an external decoder, and transport the audio to it using electrical digital output (S / PDIF) or digital optical (TosLink EIAJ).

In any case, what really matters is that the DVD got popularize the multichannel sound in domestic applications. Today we can get a built by a reader, an A / V receiver and some simple basic speakers for less than 300 or 400 euros simple equipment. But the “battle of the channels” had just begun. With the DVD now fully settled in 1999 came to theaters Dolby Digital Surround EX, that for the 5.1-channel Dolby Digital normal, added extra rear channel. The DVD does not take long to integrate this new multichannel format, which forced us to place a speaker’s, the seventh count the subwoofer if required by Dolby Digital 5.1 and DTS standards in our lounge. Yes, once again we had the opportunity to ‘track’ the sound of movie theaters, and enjoy our own home in a very similar sound experience to that offered us rooms.
Dolby continued to offer filmmakers the ability to add an additional to the soundtrack of their movie channels. He was born on Dolby Surround 7.1 format, and once again, the DVD was able to pick up the living room to bring those moviegoers that they had space to install eight speakers sound the same theaters. During all these years, as we have seen, the audio of the movie theaters and our homes have gone hand in hand.

The advent of Blu-ray Disc later represented another important step in sound quality (and, of course, image quality) because it has introduced the Dolby TrueHD and DTS-HD Master Audio, standards designed to compress the sound, but in a non-destructive way. No quality is lost. The result is a sound and impact higher resolution than DVD. It was the logical step if we consider that the Blu-ray discs available to us a capacity well above that of the DVD (25 gigabytes per layer compared to 4.7 gigabytes per layer of the latter) storage. But the escalation of channels is over.

Dolby Atmos: to channel

The latest technology developed by Dolby multichannel sound breaks radically with everything we know so far. Although delve into the workings of Atmos in another post that we are preparing, and publish later comes in handy to know that there are no more audio channels in this system. Dolby engineers wanted to halt the steady escalation in the number of channels that began with the arrival of stereo sound, and, incidentally, providing filmmakers the opportunity to decide freely in three dimensional space and the exact location of each one of the sounds of his films. And to do that, you had to “destroy” the channels.

Sound engineers who create soundtracks in Dolby Atmos channels do not work, do it with objects. We can imagine an object as a radio sound source so they do not have to worry about deciding what channel should sound every sound; only have to devote to move each object three-dimensional space of the theater, and Atmos processors transparently decide how to decompose each sound to give viewers the feeling that indeed from the point chosen by the engineers. For this to be possible, of course, must be installed on the theater’s speakers (some of them on the roof), but it is not essential to be a very high number. According to Dolby, Atmos is feasible even in rooms with only seven surround speakers (not counting those that are placed behind the screen).

Throughout the whole post we have seen how sound technologies made their way into the cinema later came to our homes. And with Atmos is happening the same. The first A / V receivers and speakers designed to allow us to enjoy this system in our living room are already coming to market. Movies with sound Atmos arrive in Blu-ray Disc format, and through streaming services. At first it seems that current BD readers will be able to extract the digital audio with this multi-channel sound, and new A / V receivers can decode it. The most interesting is probably that at home most of us can not install ceiling speakers, Dolby engineers have come up with speakers designed speakers not only in front but also at the top.

This way they are able to project sound well into the roof, and, taking advantage of the murals reflections (bouncing sound waves off the walls and ceiling), can generate a wider sound field, comparable on a small scale , which we provide cinemas with Dolby Atmos. But, as I have advance before, delve much more to this technology in another post that we are preparing. Meanwhile, if you fancy, you can check out the post they spend Atmos our colleagues at Engadget Smart Home . It’s worth a lot.