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What's the primary benefit of surround speakers? Just ambient+rear directional, or something more?

post #1 of 20
Thread Starter 
The short of my question is: given two systems with the same total cost, will a 5.1 system outperform a 3.1 system in the vast majority of home theater listening presuming a discrete 5.1 sound track?

What are the major benefits of those extra two surround channels? Do they simply play ambient sounds for a more immersive environment + directional off-screen effects for stuff like helicopter flyovers that start off screen? After all, most of the action and nearly all of the dialogue occurs on screen, a 2D planer view with a fairly limited point of view angle, so not much happens off screen in most movies, especially dramas. Or can the rear surrounds also improve the sound staging of what happens in the front channels?

I will admit that I've never listened to a quality 5.1 system aside from the heavily skewed demos in-store, like those that fly cartoon bugs all around you and amaze you with how you can tell when they are behind you. I've listened to a crappy 5.1 system before, and a quality system back in the Pro Logic days, but nothing of quality under DD or DTS sound.

The benefits of the center speaker and subwoofer are clear and obvious to me, but it's not clear why, given a fixed budget, it's better to have 4 speakers that surround you with okay sound when you could, for the same cost, have two speakers in front of you with much higher clarity and quality. The math seems even more tilted toward 3.1 if you don't care about ambient forest sounds and fly-by directionality. The old quantity vs quality argument. Am I missing something important? Am I a crusty curmudgeon stuck in the past?
post #2 of 20
Quote:
Originally Posted by prometa View Post

The old quantity vs quality argument. Am I missing something important?
Well, since you asked, I think you're missing a couple of things.

Regarding quality vs quantity, different people have different ideas of what "quality" means. For the same budget, would you trade a higher fidelity single speaker in a mono playback set-up for a pair of lesser fidelity speakers in a stereo set-up? The advantage of the better mono speaker is that dialogue, music and sound effects would be reproduced with "much higher clarity". The advantage of the lesser pair of speakers is that they can create a soundstage with stereophonic imaging. Which of those attributes is more important to you when defining "quality"?

With that in mind, creating an enveloping three-dimensional soundfield using 5 speakers might not be considered merely "quantity", especially if it creates the type of immersion that draws you into the movie better than a two-dimensional soundfield made up of speakers placed in front of you.

The other thing it seems you're missing, from your own admission, is experience. IF my exposure to surround sound had been a "crappy" 5.1 system or gimmicky in-store demos, with the only good system being from the Pro-Logic era, then I too might have been questioning the surround experience the way you are. No one can tell you what to like and what not to like; the only person that can decide your preference is you. To that end, you really ought to seek out a quality surround set-up and listen to familiar material. It gives an honest shot to the surround experience and is the only fair way to find out whether surround sound is for you.
post #3 of 20
Split the difference, 4 speakers - L, R, L surround, R surround, use a phantom center - add a center channel later.
post #4 of 20
Quote:
Originally Posted by prometa View Post

can the rear surrounds also improve the sound staging of what happens in the front channels?

can.
it acts like a compression factor squeezing the form of the soundwave into something of higher concentrated pressure.

timing..
different speaker slew (ESR?)
different speaker size (slew in the air)
those things can make a big impact like walking down the alley and getting bitten by a dog or not.
..just saying
when you combine two things, there is a chance a better combination could be had.. but only because the list of probability hasnt been shrunken down.

also..
different physical speaker location will continue to play a role in the pressure of the room if the situation is lop sided.
because accumulation will happen somewhere in the room (or a diffuse object filled in the gap) and the equidistance will be getting 'tickled' by the inside difference (known as indifference) between dry and wet signal accumulation in the room with the gap (or pocket) inside that is like a port or tube of a speaker enclosure from the inerds like living with the cables from input terminal to speaker tab laying under the table (wtf END tables?) .. the timing alignment doesnt work that much to fill in the offset gap on the first direct measure.

(saying yes.. you can get a stiffer soundstage after playing with the distance settings)
level world we speak in (not flip my burger or write this down on paper)
post #5 of 20
Quote:
Originally Posted by prometa View Post

The short of my question is: given two systems with the same total cost, will a 5.1 system outperform a 3.1 system in the vast majority of home theater listening presuming a discrete 5.1 sound track?

It is my impression that most of our focus while listening relates to the front speakers.
Quote:
What are the major benefits of those extra two surround channels?

Mostly ambience.
Quote:
Do they simply play ambient sounds for a more immersive environment +

Pretty much
Quote:
directional off-screen effects for stuff like helicopter flyovers that start off screen?

Actually, those can be pretty immersive with a 2.1 or 3.1 system.
Quote:
After all, most of the action and nearly all of the dialogue occurs on screen, a 2D planer view with a fairly limited point of view angle, so not much happens off screen in most movies, especially dramas.

Yes.
Quote:
Or can the rear surrounds also improve the sound staging of what happens in the front channels?

Not so much. After all, they are in the rear.
Quote:
I will admit that I've never listened to a quality 5.1 system aside from the heavily skewed demos in-store, like those that fly cartoon bugs all around you and amaze you with how you can tell when they are behind you. I've listened to a crappy 5.1 system before, and a quality system back in the Pro Logic days, but nothing of quality under DD or DTS sound.

I've logged a goodly number of hours listening to what is by many accounts a very very good 7.1 system.

I'm mostly aware of the fronts and rarely notice the rears.
Quote:
The benefits of the center speaker and subwoofer are clear and obvious to me, but it's not clear why, given a fixed budget, it's better to have 4 speakers that surround you with okay sound when you could, for the same cost, have two speakers in front of you with much higher clarity and quality.

IME a lot of commercial theater systems have pretty unimpressive speakers at the rear compared to what they have in the front.
Quote:
The math seems even more tilted toward 3.1 if you don't care about ambient forest sounds and fly-by directionality. The old quantity vs quality argument. Am I missing something important? Am I a crusty curmudgeon stuck in the past?

I tend to agree with you even though I've logged all that time listening to a very very good 7.1 system.
post #6 of 20
Thread Starter 
Quote:
Originally Posted by sdurani View Post

Well, since you asked, I think you're missing a couple of things.
Regarding quality vs quantity, different people have different ideas of what "quality" means. For the same budget, would you trade a higher fidelity single speaker in a mono playback set-up for a pair of lesser fidelity speakers in a stereo set-up? The advantage of the better mono speaker is that dialogue, music and sound effects would be reproduced with "much higher clarity". The advantage of the lesser pair of speakers is that they can create a soundstage with stereophonic imaging. Which of those attributes is more important to you when defining "quality"?

Yes, you make a good argument. I wouldn't deny that for many an immersive experience is more important than some perceived sound "quality". I think we agree on what the purpose of the rear speakers is, though, right-- I'm not missing one of their primary purposes?
post #7 of 20
As someone with a 7.1 setup who likes to play I can tell you that the surrounds are doing a whole lot more than you realize. If the speaker system is balanced properly the surrounds should blend in with the rest of the speakers, not stick out. If the surrounds are say too loud on the volume scale they can be distracting, but when they balance with the entire system it pulls you into the movie. I've turned the front 3 speakers off and turned on just the surrounds for fun and to see what the surrounds are doing and they seriously compliment the front 3 by extending their sound. Not just the obvious stuff like helicopters flying by but they produce alot of ambiant noise that just envelopes you. When music is playing they usually add a bit to the music, sometimes even adding instruments that are not present in the front 3, when somoene is talking there might be a slight echo reproduced in the surrounds, when someone is walking through the woods you can hear the wind and the crickets in the surrounds, etc etc.

The different is basically 2d vs 3d. Do you want to hear the movie in front of you or do you want to be in the middle of the action?
post #8 of 20
about being pulled into the movie by the speakers ..
the width of the soundstage isnt supposed to be bigger than the screen.
i've seen it on a tiny computer screen with wall to wall soundstage and it looked like a toy with an itty bitty screen in the middle as i stood in the doorway watching it play.
post #9 of 20
5.1 ( 7.1, 7.2, ) System + video is Home Theater. Do you remember the excitement when you go to a cinema for action movie.? You hear sound all around you. They come from the front , center , the sides and back. They made it multi-tracks to entertain you.
Home Theater (HT) is cinema in your home. Also the decay and ambient like concert video are very difficult to achieve with only 2 front speakers in domestic room.
Once I went to Bose for a demo of their HT system, small spk and a network- server case Sub-woofer, All 7+1 spk played different sound tracks to make complex SURROUND playing. This sensational effect cannot be achieved by 2, 3 .1 system.
Edited by TLCW - 11/23/12 at 9:21am
post #10 of 20
Quote:
Originally Posted by anwaypasible View Post

the width of the soundstage isnt supposed to be bigger than the screen.

No way! How boring that would be! eek.gif
post #11 of 20
Quote:
Originally Posted by kiwi2 View Post

No way! How boring that would be! eek.gif

how boring and embarassing it is now.

i havent touched the large flat screen market a SINGLE time yet .. i've sat back and watched a hundred thousand people make the mistake of buying a new high resolution screen and then they dont sit up close enough to see the high resolution in all of it's glory .. and the final result can still be compared to a really REALLY good 480p signal.

your peripheral vision has limits...
your television should be at those limits, or in the middle where the peripheral vision ends and the front-facing vision begins.

word is..
those televisions can be made to 1,000 inches
it isnt a single bit of effort to build them.. but getting them into a box .. shipped to the store .. and inside the store with enough room for half a dozen
plus getting it to fit in or on a vehicle to get it home
all that adds up .. it makes those larger screens more of a problem than a tool.

and that simply means people got rid of the thick entertainment center and learned what it ment to enjoy some more space in the room.
but
next they are going to want to get a bigger screen and a projector.
..and that means the projector business will be seeing more light in advertisement|promotion

too many people forget..
your television is basically a grid.
that grid has dots per inch.
the number can go up or down.
once that number is there.. you can stretch those dots (but you cant always shrink them because there isnt enough physical room).
when you stretch the dots.. you can still get the same high dot per inch resolution with the bigger diagonal surface area .. and you can sit back further and see all the dots.

if your screen is small, you will know the dots per inch go up ... but that doesnt mean you are REALLY seeing every single dot.

want some more funny?
what about the people that melt their own glass and build themselves a projector lens that fits over an LCD monitor that is less than 30 inches and it casts a screen size over 100 inches?
i mean seriously.. the television behind the glass went out and you run to the store to get a 20 inch LCD screen that costs you $150 to get a 100 inch viewing area ... and the rest of the people are spending $1,000 to get 60 - 70 inches in their living room.

yeah.. a lens, some magnification .... they take all that nice new convergence printed onto the screen and bend it again with the plastic or the glass used to create the projection.


not enough people playing with materials like that.
i remember 80-90 inch CRT televisions hanging on the wall angled downwards and you could walk inside the tube.
post #12 of 20
Quote from arynk :
" directional off-screen effects for stuff like helicopter flyovers that start off screen?

Actually, those can be pretty immersive with a 2.1 or 3.1 system.".

As one above also pointed out, video of helicopter flew from behind the audiences and gradually became visible on the screen,
also,screens like somebody got shots on his chest in video while multiple guns were actually shooting in many positions behind the audiences.
We get sensational scenes and audio effects because of surround sound.
These delay and reflected sounds, I have not found a 2.1 , 3.1 can do it for HT room.
Can the Surround Bar do so? I don't know. Anyone input to this is welcome.

Also I agree that it is too boring if sounds are within the screen even the screen is 150-200" , ... well, except video like Carnegie Hall sonata concerts.
Edited by TLCW - 11/24/12 at 12:56am
post #13 of 20
I take it then that 11.x is out of the question?
http://www.avsforum.com/t/1435778/moving-past-7-1-5-1-into-9-1-11-1-upgrading-your-ht-room-via-audyssey-dsx-or-dolby-pl-iiz#post_22528318
dsx_480x335.jpg
http://www.audyssey.com/audio-technology/audyssey-dsx
Quote:
Why use more speakers?

Research in human hearing shows that we can hear many more directions than what current systems provide. We use the direct sound to localize the direction of sources and the reflected sound to perceive the size of the soundstage.

Experiments have shown that human localization is better in front than to the sides or behind. This means that for front-weighted content such as movies and most music, good engineering dictates that we employ more channels in the front hemisphere than the back. Imaging is also better horizontally than vertically and so good engineering also dictates that channels must first be added in the same plane as our ears before going to higher elevations.

Perception is not the only factor. The physics of room acoustics for music have been well studied, and their correlation with subjective impression increasingly understood over the last 30 years. This research has shown that we have strong built-in preferences for the direction, frequency response, and time of arrival of reflected sound. Additional channels and surround sound processing are needed to properly render these components.

Proper acoustics also helps, but that's the topic of many-many threads already.......
Edited by mtbdudex - 11/24/12 at 2:14am
post #14 of 20
if your screen was wall to wall and you had speakers installed flush with the walls (except maybe the basket and surround for the cone)
those back speakers could help once again because the side speakers put all that pressure in and are already doing about 80% of the audio.. they are at a limit

then the rear speakers come in .. they arent doing anything at all .. they can help add to the last 20%


what would be a good example of this?
well...
imagine you are watching a video on the wall to wall screen and the room is completely full of pressure to represent the pressure in the room on the screen.
with that pressure dialed in..
the actor could lean over a table and throw the voice down towards the table ... and then you could hear the soundwaves from the actors voice bounce off of the items on the table.

people dont remember what it is like to hear somebody lean over a table and their head goes about halfway.. and they are facing down towards the table so the soundwaves reflect
and then maybe the person tilts their chin in to point the soundwaves back towards the seat and it fills in that whole area with a pocket of air and soundwaves ?

i used to focus on other people real sharp like .. as if i was watching and waiting for some twinkle of difference to inform me something.


..but yeah
i dont think the bit-depth is high enough yet to consider hearing audio splashing from a table.


truth is..
if the front speakers are really busy
you could ask the back rear speakers to play something entirely different that needs to be added to the sound at the listening position.
because if you've got complex audio and shove it down the speaker .. the speaker will play what it can and the rest wont be heard.
there are two ways to break down the complexity:
1. you cut it in half and feed one chunk to the front speakers and the other chunk to the rear speakers
2. you try to simply lower the volume of the complex sound as if that is going to get you an extra 50% clarity


those back speakers can get the soundwaves up front in front of your face if the soundwaves know how to play a game of frogger.
because those other soundwaves from the front (or even the side speakers) are going to be the cars on the road to avoid.

just another reason showing how the time delay is important.
post #15 of 20
There are 4 things in a home theater that impress people who dont have home theaters.

Surround Speakers
Sub Woofer
Large screen
Cup Holders

These are the things that they remember. Why? Cause they are cool and most people dont have any of these things at home.
post #16 of 20
Quote:
Originally Posted by drunkpenguin View Post

There are 4 things in a home theater that impress people who dont have home theaters.

Surround Speakers
Sub Woofer
Large screen
Cup Holders

These are the things that they remember. Why? Cause they are cool and most people dont have any of these things at home.

Throw in there:
-appropriate acoustics for clean soundstage, imaging, and tight bass (short decay time)
-power reclining chairs
- scope screen
post #17 of 20
Quote:
i remember 80-90 inch CRT televisions hanging on the wall angled downwards and you could walk inside the tube.

Were Alice and the mad hatter in there too?
post #18 of 20
Quote:
Originally Posted by mtbdudex View Post

Throw in there:
-appropriate acoustics for clean soundstage, imaging, and tight bass (short decay time)
-power reclining chairs
- scope screen

My theater is accoustically treated, people think it's for looks. I also have a scope screen with a scope lens attached to my projector, nobody ever comments on screen shape. They like the 120" screen but nobody says cool its a scope setup! In fact my dad thought the screen was too long!

Even the other people in my house barely notice the minor tweaks I do. Its more of a "make dad feel good by saying yes" kinda thing.

The average person doesn't care about the little details that we on this site care about. My mom came to town and asked me if I had bose speakers. eek.gif I bout had a heart attack!

The number one item the average person says my theater is missing is a Popcorn Machine!!
post #19 of 20
Quote:
Originally Posted by drunkpenguin View Post

Quote:
Originally Posted by mtbdudex View Post

Throw in there:
-appropriate acoustics for clean soundstage, imaging, and tight bass (short decay time)
-power reclining chairs
- scope screen

My theater is accoustically treated, people think it's for looks. I also have a scope screen with a scope lens attached to my projector, nobody ever comments on screen shape. They like the 120" screen but nobody says cool its a scope setup! In fact my dad thought the screen was too long!

Even the other people in my house barely notice the minor tweaks I do. Its more of a "make dad feel good by saying yes" kinda thing.

The average person doesn't care about the little details that we on this site care about. My mom came to town and asked me if I had bose speakers. eek.gif I bout had a heart attack!

The number one item the average person says my theater is missing is a Popcorn Machine!!

sorta OT but what the heck, it's cyber monday!

Here ya go
http://www.amazon.com/exec/obidos/ASIN/B001CMV5LI/thesunrises-20
Quote:
Price: $399.99
Sale: $149.99
Deal Price:
You Save: $250.00 (63%)
images?q=tbn:ANd9GcSekSKU0jNj2bOYS8naQkhj5eWovVp6H6Ljp5WbCgUnxdsr7L4RHBA_j7Y
post #20 of 20
Back on topic:
prometa, you need to visit a "real" home theatre near your home and hear/judge for yourself.
Look in the "area home theatre meets" forum.
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