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Why 7.1 Surround Sound is Overkill For Most Homes
RX8 writes "Home Theater expert Mark Fleischmann explains why you should not fall for the 7.1 hype and why 5.1 surround sound is adequate for most homes. From the article: 'With the marketing of 6.1 and 7.1 surround, the industry has decisively outwitted itself. It has convinced many consumers to buy new receivers and more speakers. But it has also undermined the 5.1-channel standard, which is more appropriate for the home, slowing the acceptance of surround sound in general.'"
Most non-tech people i know already have to make an effort to place two stereo speakers correctly in their livingroom,
placing six or eight is often too much trouble.
European Linux user, living in Antwerp
True - and there's a pretty cool demo of what you can do with two speakers (well, headphones) here: http://www.dolby.com/consumer/technology/headphone .html.
Of course this is a good example of why multiple speakers is a GoodThing(tm). The human ear is pretty good at telling where a sound came from (based on echos, etc). Doing what they do in the demo above would be pretty tricky if your speakers weren't stuck to the side of your head.
When I was in school, I set up some ambience speakers "left minus right". Very easy, just connect the front two speakers like normal. Then connect a second set of speakers to sides and behind the listening area -- except only connect the positive terminals to the amp, and then bridge the negative terminals between the speakers. I about jumped out of my skin the first time I listened to some old "Dead Can Dance" album and it sounded like the shaman's rattle was right behind me. Hmmmm, maybe I'll set that up again -- except the extra wires are a real drag. Oh, Roger Water's "the pros and cons of hitchhiking" was great on this setup too.
What changed under Obama? Nothing Good
Games need hardware that do 3D positional audio because the scene is unpredictable. It needs to be calculated on the fly. Any 3D positional effects in a movie would be static, added when
the movie is mixed, or else you'd have to include all the seperate audio tracks.
Such effects are difficult to pull off in a large area like a movie theatre, and would be
very dependent on the speaker configuration, which is probably why you don't see a lot of this.
A witty
I did like one point: why would you want more rear speakers than front? The center speaker produces the majority of dialogue in a movie, not the rear channels.
I have a 6.1 system, yes. I didn't intentionally do this. I watch non-digital TV with PLIIx decoding, and watch my movies with Dolby Digital EX. Frankly, I can't tell the difference. That "center surround" speaker is more for bragging rights than anything else.
So just to reiterate, I won't call 6.1 and 7.1 totally worthless, but yes, it is overkill. Movie experiences at home won't suddenly be way better. And the complete lack of 6.1 & 7.1 content makes the format rather pointless.
You can listen to any recording of say the Kronos Quartet, but no matter how well the recording tech is matched to the medium the sound is flat compared to hearing the quartet play live.
I sometimes prefer listening to something from a seminal jazz album like Bitches Brew on a turn table because the vynil has a warmer sound to my ears.
You can add all the speakers and present day tech you want it's still pancaked sound.
"Academicians are more likely to share each other's toothbrush than each other's nomenclature."
Cohen
there is difference - 7.1 receivers in same price segment will perform worse (in terms of sound quality) than 5.1, not even speaking about stereo (stereo amplifiers usually can be compared to receivers that have 2x price).
This is because price per channel - the more channels and various decoder electronics you put, the less buget you have for sound quality (cheaper tranistors, capacitors, poweer supply, etc.)
I personally have a decent 5.1 surround system. It's far from the top end of things, but noticeably better than most of the cheap systems you see for sale at Wal-Mart.
From the variety of movies that I've watched on it, my big complaint lies with the audio encoding of the movies themselves rather than with the equipment it's playing on. I have a few hundred DVDs, and there's only a handful of them where it seems that any real effort was put into the channeling of the audio. The Superbit version of the Fifth Element comes to mind as a movie that simply sounds incredible with the surround. Most of the rest of them fall short, even ones with dts.
I have a suspicion that the dts tracks on some of them were just copies of the Dolby (or even Stereo) tracks that had just been resampled at a higher bitrate. It would be like using a casette to record a song from a radio broadcast and then encoding it into a 128kHz mp3. It's still not going to sound as good as the original (The original CD... not the radio recording).
Anyway, perhaps I'm wrong but, it seems like the shortcomings in my sound system (and many others as well) is not so much the equipment, but the quality of the media being played. Anyone else seen a difference between DVD distributions of movies? Or perhaps have a preferrence in the companies you buy your DVDs from?
"Operating systems suck: you're better off using only the BIOS" --trainsaw.com
I find it distracting to hear sounds behind me (any form of surround) when the picture is in a two dimensional field in front of me. Especially when the effects tend to be breaking glass or bullets pinging off things.
First of all, light and sound are *very* different phenomenons. Light is very weird, sometimes behaving like particles and sometimes like waves, depending on what you expect from the experiment. Einstien et al knows more about this.
/Patrix
However you analogy in this case is correct, but not your conclusion.
Soundwaves can also can be compared with ripples and waves on a liquid surface. If you throw a few small stones and big rocks into a swinning pool, the waves and ripples from the impacts will interfere with each other and bounce off of the walls and corners of the pool. This is comparable to the situation in a room with speakers. The big rocks are the bass speakers, and the small stones are mids and highs.
The smaller waves from the higs and mids ride "on top of" the bigger bass waves mostly unaffected. But charateristics in the room makes the big waves move irregular and sometimes "cancel" each other when bouncing in the corners. This affects the ripples riding on them and creates mostly "temporal" errors - A high or mid frequency sound does not reach your ears at the exact right time, which is crucial for the surround effect.
Because of this it is better to transform the sound signal as close as possible to the place where it should be in the virtual sound space, not letting the "chaotic" wave situation in the room affect it. And this in turn, concludes that more speakers are preferable.
This is all very theoretical, and in a normal living room 5.1 is plenty I would say. In larger rooms however many speakers can be critical to create a good virtual sound space.
If waves did not interfere with each other this way, two speakers would be enough to create perfect 360 dgr surround sound anywhere. This is known as "virtual surround" and works flawlessly in a echo free room. In a real room the problems mentioned above makes it less effective.
Regards
Men can tell the difference between sound coming from the front or back due to the acoustics of our ears.
I use 4.1 at home. Even the '.1' is superfluous if you have speakers with good bass already.
There's no need for a central speaker if the imaging is sufficient on the speakers you have. Most speakers have highly directional tweeters, but ones on speakers such as those made by Anthony Gallo are multidirectional, allowing many listeners to enjoy a solid 'image' from two speakers -- i.e. being able to hear sound coming from what sounds like dead centre and not one or the other front speakers -- without having to sit in the central 'sweet spot'.
I love the look on the faces of friends when I play them something and they spend 5 minutes searching for the nonexistent source of the sound they can clearly hear coming right from my plasma screen, even though the speakers are six feet away on either side.
And here's why.
I had a TV with built in 5.1 surround (including some lousy satellite speakers but no sub), but it didn't support DTS, and without a receiver of some sort I couldn't add additional inputs.
So I decided to buy a 5.1 receiver and speakers.
At the store, they had a 7.1 receiver which I'd read reviews of, and they said sounds like it cost well over £1000 but was only £300. They had it reduced to £250.
So I bought it. And a set of 7.1 speakers (the same price as an inferior 5.1 set) in which the rear 4 can be spliced together as pairs - reducing it to 5.1).
Since I have a small room, and no 7.1 source, I've left it as a 5.1 system, but it's nice to know if I ever get a larger room I can split up the rear speakers and properly fill in the rear channels.
That said, I agree wholeheartedly that I'd not swap a 5.1 for a 7.1 system, if it cost more. I went from a sort of 5.1 to a real 5.1 for a sum I was happy to pay - and can now upgrade to 7.1 should it prove useful for the cost of two speaker stands.
Mark
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Because half the time, it's not the speakers that are the crappy bit, but the power supply for the amplifier.
After thirty years or so, we've got good enough at making op-amps with a decent gain-bandwidth product. Any amplifier you can buy will amplify, and will do so closely enough to ideally over a band easily broad enough for the human ear. That's not the real challenge anymore. The loudspeaker is important, but there have been improvements in both manufacturing precision and the understanding of the underlying physics. Even cheap speakers are reasonable as compared to what people used to put up with in the past.
Where it's all gone Pete Tong is in the power supply serving that amplifier.
The proper way to construct a multiple-channel amplifier is to have a very low pass filter -- series choke and parallel capacitor -- between the PSU proper and each of the individual power amp stages. This presupposes "star wiring": the current drawn by one power stage should not have to pass through a conductor which is also serving another power stage. Otherwise, you can get crosstalk induced from one channel to another. Each power amp stage needs a big hefty capacitor to supply the energy to handle loud passages between peaks of the mains, with a smaller ceramic -- not polyester -- capacitor across it to shunt out high frequency noise. {A separate PSU per power stage would be ideal; any crosstalk would have to make it all the way to the mains wiring, whose internal impedance is closer to a short circuit than can easily be made in the laboratory.}
Cheap, crappy multi-channel amps have all manner of nasties, like power rails that run across from one stage to another and under-rated capacitors that can't cut the mustard. In fact, the transformers used are frequently under-rated for the application: if you run the amp continuously just at the onset of distortion, the power transformer's thermal fuse will fail. That, by the way, is part of the reason why audio amplifiers generally use transformer power supplies. Part is that you can get a very nasty crosstalk between audio and the near-ultrasound at which SMPSUs tend to run, causing sounds to be heard that were not present in the original; but the other part is that big, chunky transformers heat up slowly and are generally more tolerant of abuse.
The reason why this situation has arisen is that manufacturers are designing down to a price point, and not up to a standard. And as long as there are more than a certain critical mass of gullible idiots out there who will pay good money for any old shite as long as it's shiny shite, I don't see any way out of the situation without some form of government intervention.
Je fume. Tu fumes. Nous fûmes!
Prior to 5.1 movies, that was always the argument against "quadrophonic" surround systems, too.
The argument was, if you pass on surround, you were giving up a tiny bit of ambiance imaging, but you had twice as much money to spend on good stereo speakers, and could buy a much better amp.
It's still true. For what I spent on my home theater's audio set-up, I could build a downright orgasmic stereo listening room... but my desire to watch movies in 5.1 trumps my craving for maximizing my hi-fi ! for $.
Besides, Hi-Fi ain't what it used to be... it's better and cheaper. Thanks to the computer revolution of the 80s and 90s pushing down the cost of transistors, I can buy a $100 stereo amplifier which kicks ass all over stereo amps which cost twenty times as much back in the 70s. My $500 5.1 amp does a fine job at faithfully reproducing music.
Quality speakers have come down, too. Again, thank computers. Home-brew acoustic design software de-mystified the art of building speakers a little bit, and launched a new wave of small-name designers.
My B&W speakers (Bowers & Wilkins, a British speaker-builder) sound downright glorious, and even with the center channel, they cost less than the kit my father once used to build his own I.M. Freed subwoofer/satelite combo. Plus, he had to deal with an expensive cross-over amp, while my powered sub enjoys the discrete 5.1 subwoofer signal with far less hassle.
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