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Discussion Starter · #1 ·
Is a 4.1 setup (no center) a big drop off from a 5.1 system? I'm thinking about buying 4 good speakers and a receiver and not buying a center channel. I know most receivers have some kind of phantom center mode to get the dialogue from the left and right fronts. I really don't have anywhere to put a center and if I won't miss that much, I'd rather just do without it.


Any advice on why this would or would not be a good idea?
 

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You will get mixed reactions to this question. Some swear by using the "phantom" mode without a center. Others say you need a center for the people watching off center. I would say try it without and see if it works for you..
 

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i use a 4.1 setup with my computer, now although i feel this type of setup is great for gaming, i get pretty disappointed whenever i watch a movie because i got spoiled with my 5.1 setup. If your a movie watcher, i would definitely reccomend a 5.1 setup and if your just in it for games, 4.1 is great.
 

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Count me as one one thinks "phantom centers" have very small sweet spots.
 

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Count me as one of those who thinks phantom centers have small sweet spots and suffer from comb filtering or horizontal lobing error in all positions, even the sweet spot.
 

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Depends on the center you're planning to get. For big action movies, a good center speaker will deliver clearer dialog than a phantom center (since the left and right front speakers are busy delivering big explosions and music, etc.,). But a lousy center speaker might be even worse.
 

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I think it depends on your seating position. If you are set up close to ideally, in the center and equidistant from your speakers, then 4.1 might work just great. However, the more left or right of center someone sits, the less well that "phantom center" will work-- the problem being, potentially, that voices will not come from the faces on the screen to a noticable degree.


That is the big advantage of a center speaker in HT is that it anchors dialog to where it should be coming from, so it will sound natural from almost anywhere you sit.


But I do think the phantom center will work very well if you are sitting in the right place.
 

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Count my local commerical theater to have a real center speaker.
 

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The following are my opinions. Please do not take offense. (It seems that every time someone gives a dif opinion on this forum, he is attacked.)


I have on many ocassions compared using and not using a center channel. I did this w/ 2 different brands of speakers. In both cases, I found that if you are sitting dead center, then it is better, much better in 4.1. The dialog is clearer and actually sounds like it is coming from the screen(not that speaker just under the screen. Explosions, etc made no change in the clarity of the dialog. It was better w/o the center. It created a better soundstage w/ 4.1


But in 4.1, if you are just 12 inches off center, then all of the voices sound like they are coming from which ever front speaker you are closest to. And this is unbearable to me.


So, if I am alone, I put it in 4.1. If I have company,etc. I use 5.1.


Dan
 

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If you don't have room for it, then don't get one. The playback will be okay without the center speaker. IMO, the real benefit of going from two-channel to discrete 5.1 soundtracks is the full-range split surround channels. The center speaker is basically there to anchor the middle and help with intelligibility for people sitting off-axis. Since 5.1 soundtracks have discrete rather than encoded center channels, you're best off with a center speaker. But, the fold down that occurs when your receiver's setup for the phantom center is a lot more consistent and satisfactory than when the surround channel information gets steered into the mains in systems that don't have surround speakers.


Ideally, you'd want three identical speakers up front, but the horizontal center speaker was invented because the TV sits exactly where a third main speaker would ideally sit. Professional monitoring setups in mixing studios use identical speakers up front, as do movie theaters (there are no special center speakers used in screen setups).
 

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People seem to so often neglect the inevitable lobing error that results from a phantom center. This is just as bad when seated dead center as it is when seated off-center. It changes the tonality of voices and solo instruments in a very bad way, IMO. For movies, I suppose it isn't that bad. For music, it is unacceptable to me. I guess that is the primary reason why I think RPTV's aren't well suited for an environment in which serious music listening will be done. Acoustically transparent screens are the only option for avoiding compromises in audio reproduction.


Of course, there are almost always some compromises, and different people have varying levels of compromises they are willing to deal with. Currently, I'm forced to live with a RPTV compromise, though my center channel is still rather good. Look at what you can do first... if that negates any chance of a decent quality center channel, then go without it or rethink your video options. Second, look at what you want to do. If audio is way down on your priority list, don't sweat it.
 

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Good one, Ereiamjh. Does anyone know if Dolby, THX, DTS, and others ever suggest a phantom center? I know on my Lexicon pre/pro there is a choice that can be made as to a center, or phantom center so it looks like they believe in it.
 

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Quote:
Originally posted by Bigus
People seem to so often neglect the inevitable lobing error that results from a phantom center.
Bigus., could you explain "lobing error?" I'm not sure I understand this. I did not notice a change in voice tonality, but I will go have another listen. Personally, I have a front projector and thus a RPTV does not come in to play. Also, I have yet to hear speakers that were behind a screen not sound affected, but I have not listened to all of the perf sceens. Do you have one in mind that you like?


Dan
 

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Lobing error is just a technical term for comb filtering or interference between the speakers. The spacing between left and right speakers is large compared to the wavelength of sound at higher frequencies. The result is that when they both play an identical signal (as happens with much of the content in phantom center mode), the resulting sound waves create an interference pattern that covers the room, including the sweetspot. For some frequencies, the distances between peaks and valleys in this interference pattern will be just fractions of an inch... much less than the distance between your right and left ears. Even slight movements of the head (or, slight non-symmetries in the room layout) can cause significantly different frequency responses to be heard by the right and left ears. Our brains are pretty good at combining the two, but the result is often a change in tonality.


A good way to test this is to play a high quality recording of a single voice or instrument that was tracked in mono. Play it sending the mono signal to both left and right speakers, and then play it sending the signal to just a single speaker. In my experience, the stereo version may place the instrument/voice correctly, but the tonality is always different (in a bad way) from that heard from a single speaker playing the mono signal.


Sounds in real life aren't stereo... they are mono. Or, when there are many sources of sound, they are discrete multichannel. We hear a bird coming from a point source. Using the stereo effect to approximate a point source does an amazingly good job, but to my ears (and many others) there is still a difference.
 

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I will have to go and test it as you described. But my first thought is, "do you personally listen to your music system in stereo or mono?" I would suspect that you listen to it in stereo as most of us do because you find the soundstage more important than the change in tonality due to lobing effect. Same goes for movies. The soundstage is better in 4.1. If I apllied your theory, I would just put a single speaker up front directly behind the screen. I am pretty sure this would not sound as good as my 4.1 system. Maybe I am simplifying things. I will go do a sound test and get back. I truly appreciate your view point.


Dan
 

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Discussion Starter · #18 ·
Thanks for the input.


I'm still in the planning stages and really didn't have a place for the center channel to go. Neither of my main seating positions will be optimal so I'm going to buy a 5.1 system from a local dealer so I can always return the center if I feel I don't need it. I think a 5.1 will be ok and I'll try and be creative and come up with a place for the center.


Thanks again
 

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Quote:
Originally posted by Ereiamjh
I will have to go and test it as you described. But my first thought is, "do you personally listen to your music system in stereo or mono?"
I prefer multichannel playback which includes a center channel. Unfortunately, my current system doesn't include the necessary processing to extract quality multichannel ambience from two-channel recordings.


And again, it never ceases to amaze me just how good stereo (two-channel, technically) can sound. The central image is quite convincing, and in the right room the ambience can be equally good. I think there are better ways, however, to achieve quality music reproduction. I was just highlighting a technical effect, my thoughts on it, and what I consider to be "optimum." It doesn't mean that I think stereo sounds bad.


The reference to mono was only as an easy way to listen for the effect. On most recordings, I too would sacrifice a bit of tonality change for a good soundstage effect. On some recordings, such as solo vocal, piano, and other instrumental works, I would prefer mono... but have no easy way to switch my system interconnects to do this "on-the-fly."
 

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Quote:
Originally posted by Bigus
It changes the tonality of voices and solo instruments in a very bad way, IMO.
I'm curious as to whether the majority of the tonal changes are due to the center channel not being identical to the L+R. I would suspect that to be the case in most setups that don't have a perfectly matched CC.


I tried it with my setup (3 identical speakers) and the comb filtering was noticeable if you listened for it - worse the farther from the sweet spot.


BUT - it was only noticeable because I had a reference to listen against - a true CC identical to the L+R. If I hadn't heard the CC first I would find it acceptable in the sweet spot.


Would the imaging characteristics of your speakers also play a part in this?:confused:
 
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