[bigshot]

  I mean where do you get this stuff from? Do you think to yourself, "I know, let's screw with anyone thinking of getting a home cinema system by making some stuff up that's completely wrong and maybe if I post it in the sound science forum it will appear more believable"? I just don't get the point of posting something like this.

 
I'm glad your mother loves ya!
 
When you had a home 5:1 system, did you set it up to play music too? Did you have an AV amp like the Yamaha with the stereo to multichannel DSP? I used to have an older Sony 5:1 receiver but the DSPs on it were completely unusable for music. They muddled up everything with thick reverb. The technology has gotten much better in the past few years.

 

[xnor]

  In theory what you are saying is correct under certain circumstances, circumstances which are frequently not met. In large cinemas, you still end up with large and problematic stereo soundfields between the centre and left and right speakers, which is why theatrical 7.1 was invented, to provide 5 front speakers which include a centre left and centre right. This is obviously not such an issue in a home 5.1 setup,

Well you're answering your own (moot) points.
 

 , instead home setups suffer from other practical issues, where to put the centre channel for example. The vast majority of home setups do not use AT screens, instead the centre channel is placed above or below a flat screen panel or projection screen (and therefore on a different horizontal plane from the other speakers) and commonly employ a different, smaller speaker for the centre channel relative to the left and right speakers. Home users also frequently fail to appropriately delay the output to the centre channel.

The (THX) recommendation is to simply point the speaker at the listener.
 

Additionally, in practise a stereo soundfield which includes the centre speaker is often avoided in domestic 5.1 mixes. In practise, music and stereo effects frequently still use the left and right speakers (with a phantom centre), with mainly just dialogue and Foley routed to the centre channel. In fact, some TV networks specify only dialogue in the centre speaker and a phantom centre for everything else. Add all these facts up and the ideal of the perfectly smooth stereo soundfield which solves the phantom centre issues is usually not the reality in practice!

Answered partly by bigshot. There is no phantom center when you play the signal common to L/R through the center speaker.
Even if you just play dialog through the center speaker it has advantages over having no center speaker. Especially intelligibility of speech is impaired with the dips in the frequency response you get with stereo, as mentioned before.
 
 

This is a more complex subject to deal with because it deals with creative uses and the application of processes during mixing. Many senses your statement is kind of backwards. One of the reasons why you don't find as much precisely locatable sounds to the side and in the rear channels in many movies as you do in the front is because of the imaging problems. However most of what is put in the rear speakers does contain a coherent image but at relatively low levels where lack of accuracy in the rear and side stereo images is not so critical.

I do not understand what you're objecting to really. You mentioned arrays of / diffuse speakers in cinemas before, which by definition don't allow for precisely locatable sounds.
As the name suggests, they're mainly there to surround the listener / provide the atmosphere if you will. It's not impossible to put distinct sound events there but that is done seldom due to the problems mentioned.
 

In other words, you would get a better result if the side and rear stereo images were more stable, this is why Dolby EX was invented many years ago, to provide a more focused rear stereo image but EX (and the DTS equivalent) is not very commonly in domestic setups. It is also one of the fundamental design concepts of newer systems like Dolby Atmos. It would seem rather strange to invent systems which attempt to solve stereophonic problems inherent in surround sound, if as you state those problems do not exist in the first place!

Where do I state that the rear in 5.1 is problem-free? It seems you're just putting words in my mouth.. which is not nice.
In fact, I clearly and explicitly said that the rear channels won't give you perfect imaging! So What?
Just like the front center speaker "fixes" the stereophonic problems in the front, the rear center speaker added with EX improves the situation in the back. Sure is a nice addition for some movies, but so would be 22.2. Kinda off-off-topic though.

 

[bigshot]

Gregorio, you keep talking about multichannel sound in theaters for movies. I'm talking about multichannel sound in the home for listening to both 2 channel and native multichannel music. As I said before, my system is first and foremost a music listening system. Movies are secondary... however when I got my system balanced well for music, it wasn't hard at all to tweak it to work just as good for movies too. It's just a little tricky because the EQ and channel volume settings apply equally to both, but the DSPs for music have a further group of settings that have to be balanced against the global settings. It took some back and forth, because I tuned for music first, then had to adjust the global for movies, then back and forth between global and DSP a bunch of times until both were perfect. Kind of hard to explain, but there weren't any adjustments for movies that didn't affect the music too. It took parallel parking to get right.

 

[gregorio]

Originally Posted by xnor /img/forum/go_quote.gif
 
There is no phantom center when you play the signal common to L/R through the center speaker.

True but again in practise identifying exactly what is in common to L/R can be affected by the phase coherence issues common to virtually all stereo music recordings and this issue also commonly affects the position of elements placed between the phantom centre and left or phantom centre and right positions.
 

Originally Posted by xnor /img/forum/go_quote.gif
 
Even if you just play dialog through the center speaker it has advantages over having no center speaker. Especially intelligibility of speech is impaired with the dips in the frequency response you get with stereo, as mentioned before.

It does have its advantages but in practice it also has it's disadvantages. For example, speech intelligibility is frequently even more impaired in 5.1 home systems, for the reasons I mentioned before, than it is by the frequency response dips you get with stereo. This is borne out by the number of customer complaints on this issue to broadcasters by consumers using 5.1 systems relative to those listening in stereo.
 
Furthermore, original 5.1 mixes generally incorporate L/R stereo and add a centre channel option, rather than completely replacing and eliminating the L/R stereo and it's associated phantom centre. The discrete centre channel is usually used for dialogue and Foley but for many other elements (frequently the incidental music for example) L/R stereo and it's associated phantom centre is still employed. For this reason, the L/R speakers in a home 5.1 system still has to be able to produce a coherent stereo image even when operating in 5.1 mode and playing back original 5.1 material. A fact bigshot appears blissfully unaware of!
 

Originally Posted by xnor /img/forum/go_quote.gif
 
I do not understand what you're objecting to really. You mentioned arrays of / diffuse speakers in cinemas before, which by definition don't allow for precisely locatable sounds. As the name suggests, they're mainly there to surround the listener / provide the atmosphere if you will. It's not impossible to put distinct sound events there but that is done seldom due to the problems mentioned.

It is virtually never the case that the information placed in the rear speakers is not stereophonically coherent, especially with background atmospheres! It seems like you don't know what an "atmosphere" actually is in audio post terms. 5.1 was not invented and does not exist to just create a more even front stereo image with some noise behind. Why was 5.1 invented, when the system it was designed to replace (LCRS) had already been providing exactly this very successfully for nearly 20 years?
 

Originally Posted by xnor /img/forum/go_quote.gif
 
Where do I state that the rear in 5.1 is problem-free? It seems you're just putting words in my mouth.. which is not nice. In fact, I clearly and explicitly said that the rear channels won't give you perfect imaging! So What?

Exactly, What! I originally stated that while 5.1 solves some stereo issues, in practise it commonly introduces other issues, plus other new stereo issues. You are the one arguing with this, so What!
 

  Gregorio, you keep talking about multichannel sound in theaters for movies. I'm talking about multichannel sound in the home for listening to both 2 channel and native multichannel music. As I said before, my system is first and foremost a music listening system. Movies are secondary... however when I got my system balanced well for music, it wasn't hard at all to tweak it to work just as good for movies too. It's just a little tricky because the EQ and channel volume settings apply equally to both, but the DSPs for music have a further group of settings that have to be balanced against the global settings. It took some back and forth, because I tuned for music first, then had to adjust the global for movies, then back and forth between global and DSP a bunch of times until both were perfect. Kind of hard to explain, but there weren't any adjustments for movies that didn't affect the music too. It took parallel parking to get right.

I keep talking about 5.1 in theatres for movies for 2 reasons: 1. It is what 5.1 sound was invented for, it was never intended to be a home audio format and 2. You are the one who said: "You are supposed to calibrate to Dolby or THX standard, the same way movie theaters do. So you start by calibrating for movies and get that right first."!
 
You seem to be contradicting this statement now you've been called out, what you're saying now is that you setup your system for music first and then tweak for movies. That's a shame, because actually you were right the first time! You've also already admitted that the way you've set your system up does not in fact work in stereo and that you've had to carefully balance the rest of your 5.1 system to compensate for the "gaping holes" you've created in your stereo soundfield. Now you're saying that EQ and channel volumes apply equally to movie playback and to music playback when the music playback standards call for equally balanced and flat playback and the Dolby standards you said should be adhered specify different balancing between the speakers. It doesn't take "parallel parking to get right", it takes two different settings or a willingness to compromise and not get it right!
 
Look bigshot, it's your system and it's your right to do with it whatever you want, even if that means it doesn't function correctly. What I'm objecting to, is you telling others (in a sound science forum of all places) how they should setup their system to be like your (deliberately malfunctioning) system and defending your position by arguing with those, who have experienced correct 5.1 setups, that they don't know what they are talking about.
 
Quote:

But a lot of people don't set their multichannel systems up properly and don't even come close to taking advantage of what it can do.

I absolutely agree with this statement. The problem is, that you yourself are an example of one of those "a lot of people" you are talking about and quite an extreme example at that! As with most extremists, you don't actually see yourself as an extremist, you see yourself as "enlightened" and everyone who disagrees with you as blinkered. What you see as "enlightened" is in fact just incorrect and misinformed and any attempt by me (or anyone else) to point this out just apparently results in you contradicting yourself and becoming defensive, rather than questioning the validity of what you believe. This is familiar territory with many audiophiles and is why I stated I was writing these posts for the benefit of others rather than you bigshot, as you are obviously entrenched. I've done what I intended and now it's up to others who read what has been written here to decide for themselves if they wish to setup their system as you have instructed.


     
     G

 

[xnor]

  True but again in practise identifying exactly what is in common to L/R can be affected by the phase coherence issues common to virtually all stereo music recordings and this issue also commonly affects the position of elements placed between the phantom centre and left or phantom centre and right positions.

Already responded to that in #93.
 
 
Quote:

It does have its advantages but in practice it also has it's disadvantages. For example, speech intelligibility is frequently even more impaired in 5.1 home systems, for the reasons I mentioned before, than it is by the frequency response dips you get with stereo. This is borne out by the number of customer complaints on this issue to broadcasters by consumers using 5.1 systems relative to those listening in stereo.

Which reasons impair speech intelligibility with a center channel? Be specific please.
 
 

Furthermore, original 5.1 mixes generally incorporate L/R stereo and add a centre channel option, rather than completely replacing and eliminating the L/R stereo and it's associated phantom centre. The discrete centre channel is usually used for dialogue and Foley but for many other elements (frequently the incidental music for example) L/R stereo and it's associated phantom centre is still employed. For this reason, the L/R speakers in a home 5.1 system still has to be able to produce a coherent stereo image even when operating in 5.1 mode and playing back original 5.1 material. A fact bigshot appears blissfully unaware of!

Have you got nothing new? Repeating the same stuff becomes boring quickly.
 
 

It is virtually never the case that the information placed in the rear speakers is not stereophonically coherent, especially with background atmospheres! It seems like you don't know what an "atmosphere" actually is in audio post terms. 5.1 was not invented and does not exist to just create a more even front stereo image with some noise behind. Why was 5.1 invented, when the system it was designed to replace (LCRS) had already been providing exactly this very successfully for nearly 20 years?

What are you on (about)? Where did I say this? If you keep putting words in my mouth I'll have to put you on ignore. Seems like a compulsion to be correct and correct people, even if they didn't say something wrong .. then you just make something wrong up to correct.
 
 

Exactly, What! I originally stated that while 5.1 solves some stereo issues, in practise it commonly introduces other issues, plus other new stereo issues. You are the one arguing with this, so What!

/facepalm. Do I really need to re-quote the previous posts? You should really calm down and start reading the posts.

 

[bigshot]

Originally Posted by gregorio /img/forum/go_quote.gif
 
I keep talking about 5.1 in theatres for movies for 2 reasons: 1. It is what 5.1 sound was invented for, it was never intended to be a home audio format and 2. You are the one who said: "You are supposed to calibrate to Dolby or THX standard, the same way movie theaters do. So you start by calibrating for movies and get that right first."!

 
You misunderstood what I was talking about. I was talking about balancing a system to sound good with both movies and music. Decoding of movies are not adjustable like DSPs for music are. So you start by adjusting the global settings to suit movies first. Then you adjust the DSP settings for music second. I wasn't talking about music being secondary in importance. Just in order of how you go about balancing the two sets of settings when one affects the other... especially because of the sub not being adjustable within the DSP. (That's why parallel parking is required to balance.)
 
Music is of primary *importance*, because once you get it tweaked out for music, anything you play on it... movie, concert, CD... everything sounds better than a 2 channel system.
 
As for 5:1 not being for music... well, you must only listen to rock music, because 5:1 is a very established standard in classical music and opera. And there, the center channel acts as a third main up front, it isn't reserved for dialogue and effects. The front is a clear soundstage that matches the action on the screen, and the rear is hall ambience and audience sounds. I have a bunch of jazz blu-rays that are mixed that way too. Aalong with a projection video system, it can really clarify the soundstage, open up the perceived size of the room and give a realistic concert hall feel.
 
5:1 is definitely a medium that suits music well... SACDS, DVDs, Blu-Rays... there are lots of recordings that are designed specifically for naturalistic presentation of music. It does take a different sort of approach to setup than a strictly movie based 5:1 system though. That's what I'm trying to explain to you, but you keep missing the fact that I'm not talking about a typical 5:1 cinema setup. I'm talking about the modifications you make to it to make it handle music as well as it handles movies.
 
The reason that people think 5:1 doesn't sound good for music is twofold... 1) most systems are designed for movies with dialogue in the center, a booming sub and rears that have rocket ships and bullets whizzing over your head. And 2) most people who own really good 5:1 movie systems that are theoretically capable of being good music systems too have had them set up by installers who haven't a clue how to adjust them for music because they've never heard a system set up that way. Apparently even some people who engineer 5:1 sound don't know much about that!
 
By the way, the reason the center channel is there for music is so you can spread your mains twice as far apart and still maintain the recommended 8 foot space between each speaker. This makes for a larger soundstage.

 

[gregorio]

  Already responded to that in #93.

Nope, there's no mention of upmix algorithms or of the snapping effects which can occur, where exactly in post #93 was that info?
 

Originally Posted by xnor /img/forum/go_quote.gif
 
Which reasons impair speech intelligibility with a center channel? Be specific please.

You really should take your own advice and "start reading the posts"! (#99).
 

Originally Posted by xnor /img/forum/go_quote.gif
 
Have you got nothing new? Repeating the same stuff becomes boring quickly... /facepalm. Do I really need to re-quote the previous posts?

Exactly what I was thinking when I needed to repeat the same stuff!! /facepalm
 

Originally Posted by xnor /img/forum/go_quote.gif
 
I'll have to put you on ignore.

That sounds good to me! You've obviously got your idea of what 5.1 is, of how it works, how it should be set up and of how it's used. Bigshot's got his own beliefs about 5.1 too, you both obviously know more about it than those who actually create the content you listen to. So good luck to both of you, I'm sure you'll be very happy together.

 

[bigshot]

At least I have a 5:1 system in my home and I use it every day! I think you know a whole lot about a little bit of 5:1. It's used for more than just movies and TV.

 

[xnor]

  Nope, there's no mention of upmix algorithms or of the snapping effects which can occur, where exactly in post #93 was that info?

Well, how is the saying: you can lead a horse to water but you cannot make it think .. eh drink.
 
As for the other completely irrevelant point about upmixing algorithms: click me. Do you need an intro in digital signal processing too?
 
 

You really should take your own advice and "start reading the posts"! (#99).

That's not how it works. See, you didn't mention speech intelligibility anywhere there. Logic 101.
Anyway, so you're saying that if the center channel is not at the same height as the listener and if small center speakers are used then intelligibility of speech is impaired. Wow... I'm speechless.
 
 

Exactly what I was thinking when I needed to repeat the same stuff!! /facepalm

I really don't understand why you're repeating that stuff though. My best guess is the being correct all the time at all cost compulsion...
 
 

That sounds good to me! You've obviously got your idea of what 5.1 is, of how it works, how it should be set up and of how it's used. Bigshot's got his own beliefs about 5.1 too, you both obviously know more about it than those who actually create the content you listen to. So good luck to both of you, I'm sure you'll be very happy together.

More putting words in other people's mouthes. Whatever you know, nobody is gonna listen with such dishonesty and attitude.
Btw you should try it too sometimes, being happy that is.

 

[Copperears]

Sorry to see this thread get so heated!

I am convinced that properly-set-up 5.1 in the home, with a properly-recorded 5.1 disc, is an accurate listening experience that stereo cannot compete with.

The only problem for me is that the vast majority of recordings I enjoy were made during the Stereo Era, and I don't think one could remaster them to be 5.1 and improve the quality without adding something artificial to the original sound in the process.

I mean, it might be possible; since other than LCR is used primarily for ambience and phase, as has been discussed, perhaps there'd be a way to consistently and reliably extract that info out of an original stereo recording, and redirect it for its purpose to the rear speakers?

The more exciting prospect of course is if there's enough of the original master to be able to remaster it to 5.1 rather than stereo, accurately. That would be huge, and I have no idea how extensive that possibility actually is, since I don't own the original master tracks.

 

[bigshot]

Yamaha created the first Digital Soundfield Processor for converting stereo to multichannel in real time back in 1985, and their DSP technology is considered the best in home audio. I use the most recent 7.1 Stereo DSP built into my Yamaha receiver and it works perfectly... maintaining the forward soundstage and adding just enough phase to the rear to make the room feel live. It's not a drastic thing. Subtle, but really effective. I listen to all my music with it.

 

[proton007]

  Yamaha created the first Digital Soundfield Processor for converting stereo to multichannel in real time back in 1985, and their DSP technology is considered the best in home audio. I use the most recent 7.1 Stereo DSP built into my Yamaha receiver and it works perfectly... maintaining the forward soundstage and adding just enough phase to the rear to make the room feel live. It's not a drastic thing. Subtle, but really effective. I listen to all my music with it.

 
I hope you haven't patented your idea. Your description is tantalizing; unfortunately it needs to be heard to experience it fully.

 

[White Lotus]

Some (not I) would throw out the possibility that considering we only have two ears, that surround sound isn't necessary. 

 

[bigshot]

A lot of people don't appreciate how important the space around you is to sound. They think the best sound is in some sort of anechoic chamber or piped directly into your ear canal or something. But directionality, depth cues, room ambience, and the phase of the space around you all combine to add realism to sound.

 

[xnor]

  Some (not I) would throw out the possibility that considering we only have two ears, that surround sound isn't necessary. 

With the necessary DSP power (and personal HRTF measurements) this is true for headphones (might need a head-tracker for more realism), and even partly for speakers.