Cinéma maison 5.1 vs 7.1 expliqué

Le home cinéma peut être très déroutant, surtout si vous débutez. Et l'une des plus grandes décisions que vous devrez prendre est de choisir entre un système de base à cinq haut-parleurs (plus un caisson de basses, car qui ne voudrait pas de ces basses ?) ou un système à sept haut-parleurs plus puissant. Alors que toute personne ayant expérimenté des haut-parleurs et des amplis pendant un certain temps peut probablement ignorer ce tutoriel particulier, les utilisateurs débutants et intermédiaires obtiendront probablement beaucoup de bonnes informations. Même si vous souhaitez simplement obtenir un son légèrement meilleur que celui que votre téléviseur vous offre, vous en tirerez probablement beaucoup parti, et nous avons inclus de nombreux conseils et astuces. Alors allons-y et parlons des différences entre les systèmes 5.1 et 7.1.

• Avantages et inconvénients des versions 5.1 et 7.1
• Explication de la taille et de l'acoustique de la pièce
• Explication de l'étalonnage de la pièce
• Qu'en est-il des enceintes en hauteur/au plafond ?
• Dolby Atmos contre DTS:X contre Auro-3D
• Répartition des vidéos
   

Avantages et inconvénients des versions 5.1 et 7.1

Tout d'abord, un rappel rapide, afin que nous soyons tous sur la même longueur d'onde.

Lorsque nous parlons d'un système de cinéma maison, nous le faisons toujours précéder d'un ensemble de chiffres. Les plus courants sont (comme vous le savez déjà si vous avez lu le titre de cet article et que vous n'êtes que légèrement éveillé) 5.1 ou 7.1. Les deux font référence au nombre d'enceintes dans la configuration. Un système 5.1 se compose de cinq enceintes plus petites et d'un caisson de basses. Le subwoofer gère les basses, tandis que les cinq haut-parleurs supplémentaires gèrent tout le reste Dans cette configuration particulière, vous aurez un haut-parleur central qui se trouve directement devant votre position d'écoute, sous votre téléviseur. De chaque côté, il y aura deux haut-parleurs avant - ceux-ci peuvent être soit des satellites plus petits, soit de grands haut-parleurs au sol. Les deux haut-parleurs restants sont généralement assis de chaque côté de votre position d'écoute, donc un de chaque côté de votre canapé. Le subwoofer peut occuper différentes positions, mais il est le plus souvent placé dans un coin ou sur un côté de votre téléviseur.

L'un des grands avantages des systèmes 5.1, que nous aborderons un peu plus en détail ci-dessous, est qu'ils sont autonomes. Vous pouvez les acheter dans une seule boîte, sans aucun équipement supplémentaire nécessaire. Un bon exemple? Essayez l'Onkyo HT-S3910, un ensemble simple d'enceintes qui est livré avec son propre récepteur - qui, soit dit en passant, est le hub dans lequel vous allez tout exécuter et qui connecte vos enceintes à votre téléviseur.

Ensuite, il y a 7.1. Maintenant, très évidemment, c'est la même configuration avec deux haut-parleurs supplémentaires ajoutés - seulement c'est là que les choses commencent à se compliquer. Ces deux haut-parleurs supplémentaires pourraient être identiques à ceux situés de part et d'autre de votre position d'écoute, uniquement placés derrière celle-ci. They could be height speakers, that are bolted to the wall, facing downwards. This is where you really start to get the full surround sound effect. If you’re looking to get involved with this many speakers, try something like the Klipsch 7.1.2 System.  It doesn’t come with its own receiver, but that’s not uncommon among bigger systems.

Of course, you can go bigger. Much bigger. By now, you’ve probably worked out the numbering system, so if we tell you about a 9.2 or 11.2 system, you’ve almost certainly got a good idea of what this entails. It can actually get quite complex – we’ve seen systems that are 9.2.4, which is nine surround speakers, two subwoofers, and four speakers installed in the ceiling. On a related note, Mad Max:Fury Road sounds badass through that system.

Whichever home theater system you decide to go for (and were going to stick to 5.1 and 7.1 here, otherwise we’ll be here all day) you need to be aware of the pros and cons.

5.1 first. It’s got several distinct advantages:the systems usually come in a single box, as we’ve mentioned, meaning there’s no need to invest in additional components - although of course, that's always an options. They are also relatively easy to set up and place, which can be a real boon for smaller rooms. They are inexpensive – it’s possible to get a good 5.1 system for under $1,000 – and depending on the receiver they come with, eminently customisable if you ever decide to go that route. And even if you buy the cheapest one available, it’s going to be an immediate upgrade to the sound coming out of your TV. You’ll notice this the moment you watch a movie, or play a game, or load up a series on Netflix, or do anything that has surround sound capabilities.

You're also far more likely to find wireless systems here - and for anyone who has ever spent an afternoon stripping and twisting speaker wire, that's probably a huge relief. If you’re into checking out wireless systems, they come in both 5.1 and 7.1 variants. For 5.1, try the Enclave Audio Cinehome II.

Of course, they do have a downside. A couple, actually. They can feel underpowered, compared to bigger systems, and they simply don’t have the depth or precision of those setups. More importantly, if you are in a larger room, they are simply not going to be adequate. For the most part, these systems are composed of satellite speakers, which are small and light, and can be placed easily. That’s fine – but it does come with the caveat that they aren’t going to be nearly as powerful. In addition, while wireless systems are far more convenient, in that they don’t clutter up your listening room with wires, sound quality can sometimes suffer, and you will need to plug each speaker into a power socket. Wired speakers almost always sound better, but do have the disadvantage of needing ugly speaker wire, which you’ll almost certainly have to purchase separately.

7.1 systems, on the other hand, make their advantages known immediately. Increasing the number of speaker channels gives you richer surround sound, and at the price ranges they usually operate at, the speaker build quality and audio capabilities are usually way, way ahead of any 5.1 system. While not all packages come with the receiver, they do demand that you have one, and any you invest in will almost certainly allow you to easily upgrade your existing system, should you choose to.

Downsides? 7.1 systems can be expensive. Actually, scratch that can – in almost all circumstances, they are pretty pricey. The only way they wouldn’t be is if you take a 5.1 system, swap out the receiver for something with a bit more meat and more channels, and add in a couple of additional satellite speakers, but this Frankenstein -like configuration is never going to be a patch on a purpose-built 7.1 system. And if you try to deploy a 7.1 setup in a small room, you’ll quickly find that the sound becomes muddy and unfocused, as you need a little bit of distance between you and the speakers to get the effect you’re looking for.

So, here are the key things to bare in mind when choosing:

• How big is your room? If it’s larger than around 350 square feet, consider a 7.1 speaker setup. If it’s smaller, a 5.1 may be more appropriate.
• Where is your listening position? Do you have room behind it? If so, consider a 7.1 setup.
• What type of furnishings are in your listening room? How many flat surfaces do you have in relation to the number of soft surfaces or bookshelves? We'll go into this a little more below.
• Are you likely to want to upgrade your surround sound at any point? Could you see yourself investing in height speakers? If so, go for a 7.1 system, with a compatible receiver.
• Do you prefer wired or wireless systems? If you need excellent sound and don’t mind wires, then go for wired. If you can compromise a little on sound, and have multiple plug points available, go for wireless.

Room Size And Acoustics Explained

When you’re deciding which system to go for, this is probably the most important thing to consider.

It’s not just about a system being unable to fill a larger room, or a system that is too big swallowing the space in a smaller room and muddying the sound – not to mention taking up actual physical space with speakers and speaker wire. It’s what’s in the room itself.

Ideally, we’d all have a dedicated rectangular media room, with a listening position on a comfortable couch (with La-Z-Boy functionality and built-in cup holders, if you please), with walls that have been acoustically proofed, and speakers that are in precisely the right position. But most of us don’t. The vast majority of us don’t. For most people, the 5.1 or 7.1 system will be installed in a lounge or living room, and it will be filled with objects that will do funny things to the sound.

Bookshelves. Coffee tables. Vases. TV stands. Paintings. The bicycle that you’ve told your ten-year-old a million times not to leave in the living room. On top of that, there’s a pretty good chance your couch is probably pushed up against the wall, or at the very least, not exactly in the ideal listening position for the space. You might want to position rear speakers on speaker stands behind you, but they might very well get in the way.

Broadly speaking – and we really are talking very broadly, because acoustics is a vast science – there are objects that are good for sound, and objects that aren’t. A full bookshelf does good things to sound, because it absorbs the majority of the soundwaves, allowing you to hear what’s coming out of the speakers more precisely without it being muddied by reflections. Ditto for couch cushions, drapes, beanbags… Anything soft or uneven, really. On the other hand, walls, ceilings, paintings – anything flat and reflective – is going to complicate things as they reflect sound waves back into the room. In extreme cases, two parallel walls will create what is known as a standing wave:a low-frequency resonance that pops up as sound is reflected between them.

Ultimately, a good way to approach it is as follows. Evaluate the size of your room – anything up to 350 square feet (roughly) will be just fine with a 5.1 system, while anything above that would almost certainly benefit from a 7.1 system. Take a look at what you have in the room, and if possible, try to maximise bookshelves and soft furnishings (especially the bookshelves, because books are cool). Then pick the type of system that suits the size of the room.

And look:we know this is inexact. Nous comprenons cela. Every single room is going to be different, and all we can do is provide some general principles. As long as you’re aware of them, and pay attention to your surroundings, you should be fine. If you’d like more guidance, check out these setup diagrams from Dolby.

A word on subwoofer placement. Placing the surround speakers is relatively simple:centre speaker under the television, front speakers on either side, and side speakers on the left and right of the listening position. Rear speakers behind it (for 7.1), roughly mirroring the position of the front speakers. But the subwoofer needs to go at floor level, Which opens up a whole can of worms.

Traditionally, the subwoofer is placed on one side of the TV, or in the corner, or in some cases along the side of one wall, pointing inwards. If you can, try to keep it close to the front speakers, which will help the illusion that the bass is coming from there. A good way to fine tune placement is as follows:put the sub, wired up, in your listening position – we know it’s weird – then, with something playing, walk around the room, or even crawl around at floor level. See where the bass sounds best. That’s where you want to put your subwoofer. And just remember:good base isn’t just loud, it’s also rounded, clear, and accurate. It shouldn’t blow your head off. Or your neighbors’.

Room Calibration Explained

Some slightly more expensive systems offer a fantastic way of getting the most out of your setup, which is room calibration.

Essentially, this allows the system to fine tune the performance of the speakers to suit a given room, which (inappropriate room size aside) will help get the most out of your purchase. How this works is that usually, the receiver will come with an external microphone, that is connected to it and placed in a series of listening positions around the room. The receiver plays a variety of test tones, which are reflected around the room and captured by the mic, essentially giving the receiver’s processors a picture of your listening environment. When it’s got this, it can use its built-in equalisers to adjust what you’re hearing, in order to maximise the clarity of your system.

Calibration systems do vary – and they are much more common in 7.1 then 5.1 systems. And in most cases, you'll hear an immediate improvement in your sound, especially in your regular listening position. It's the kind of thing which can make a major difference, and where possible, we'd urge you to go for it.

But what if your system doesn’t come with room calibration? Not to worry. You can still do it – although it’s a little more complicated. You’ll need to invest in something like the Digital Video Essentials:Optimize Your Home Entertainment System DVD.

What About Height/Ceiling Speakers?

Let’s put it this way:we all want height speakers. But most of us don’t need them.

For starters, the more speakers you add onto a system, the narrower the range of entertainment that can actually provide dedicated channels to those speakers. Almost all Blu-rays these days are capable of high level surround sound mixes, so if that’s what you listen to, then you should absolutely invest in them. But if your entertainment diet consists of cable news, or Netflix, or even most video games, then chances are height speakers will be wasted on you. Not in the sense that you want appreciate them, but in the sense that they won’t be performing to nearly their full potential.

Oh, they’ll still make noise. In some cases, beautiful noise. The problem is, it won’t be noise specifically designed for height systems. It won’t sound off, or wrong, but it won’t be nearly as good as it could be.

Then there’s placement, which for height speakers, can be a pain. You’ve either got to bolt them to the wall, or position them on a high bookshelf. Depending on whether you own or rent, the former may be unachievable. If you are thinking of checking out height speakers, you could do worse than invest in the absolutely superlative SVS Prime Elevations (full review here). They not only do the job of height speakers, but their angled body and multi-placement options mean you can use them in a number of situations.

Ceiling speakers - as in, ones actually installed into your ceiling - are a little bit trickier. The principals are the same but the actual installation process and oodles of speaker wire are not, and you'll need to be really convinced they'll help before you embark on knocking holes in your roof. By all means, go for it, but be aware that it's tricky.

Dolby Atmos Vs DTS:X Vs Auro-3D

There are three main types of software – codecs, to use the technical term – that allow your system to process surround sound. These are Dolby Atmos, DTS:X (the most common) and Auro-3D  (highly specialist). We’ve actually got a full explainer for the three different types right here, but if you need a TL;DR:

DTS:X is probably the simplest. It doesn’t require a minimum number of speakers, and is purely software-based. It’s also got excellent conversion capabilities, turning even audio that doesn’t have surround sound mixing into something that can be put out through a surround sound system.

Dolby Atmos is a piece of software that uses height or ceiling speakers, and specifically requires them. You will almost never find this on setups below 7.1, although if you have the room size in the budget, it’s well worth experimenting with.

Then there’s Auro-3D :a highly specialised, deeply cool speaker setup that relies on something called the Voice Of God speaker, which is installed in the ceiling. This is the least common of the three, although its integration is becoming more widespread. 5.1 users definitely need not apply. Come to think of it, you couldn’t run a conventional 7.1 system through it either; by definition, adding height speakers would turn it into a 9.1 or even 11.1 system.

Just remember:knowing about these is helpful, but shouldn’t affect the system you pick. You should choose the right number of speakers for your room, and calibrate them correctly, rather than worrying about the type of surround sound codec. Consider this extra information.