Dual Center Channel

[ruttnut]

Need some expert advice. My design for my HT includes Dual center channels. I have one place below a 92" screen and the second,(same speaker) above the screen tilted down at 10 degrees (pointed at the second row). My intention was to get the effect that the voices are coming from the center screen. Is this a mistake? I had an HT designer tell me that it could result in just the opposite of what I'm intending....perception that the voices are coming from multiple directions....:confused: I didn't buy that. Your thoughts? Thanks

[mazersteven]

Need some expert advice. My design for my HT includes Dual center channels. I have one place below a 92" screen and the second,(same speaker) above the screen tilted down at 10 degrees (pointed at the second row). My intention was to get the effect that the voices are coming from the center screen. Is this a mistake? I had an HT designer tell me that it could result in just the opposite of what I'm intending....perception that the voices are coming from multiple directions....:confused: I didn't buy that. Your thoughts? Thanks

I would say it's a mistake.

If you keep the center channel below the screen and angled toward the listeners. Once properly calibrated you will think the voices are coming from the screen.

[billnchristy]

Yeah I agree that its a mistake, though it might be possible to have a pair toed in at either side and it would work like a phantom center...though really a single one would be the best choice and easiest to implement.

[no. 5]

Yeah, you really don't need to do much to fool your mind into thinking that sound is coming from where it isn't.

In fact, you could place the center channel right over your head, and in a few minuets you would be hearing the dialog coming from the center of the screen (of course, the effect would disappear when you started paying attention to where the sound is coming for, instead of the movie).

If you really wanted dialog to cone from the center of the screen, you could get a acoustically transparent screen and put the center behind it.

[sivadselim]

If you keep the center channel below the screen and angled toward the listeners.
Actually, placement of the center channel speaker above the screen is the best location if you do NOT want the speaker's sound to be localizable. Our ears are designed by nature to hear and localize sounds that come from below us better than those that come from above us. Just look at them. Evolutionarily, this is so that we can hear and localize our offspring, our prey, and our predators more accurately, as these sounds would usually come from below us as opposed to above us (except, maybe, pterodactyls :)). By the same token, if you do NOT want the center channel to be localizable, whenever possible, placement above your screen is preferable to placement below it.

[no. 5]

I have my center above my TV, trust me, it's localizable if you let it. :)

[emorphien]

I have my center above my TV, trust me, it's localizable if you let it. :)

I think it's fairly localizable either way, I agree. As long as it's not too far away, wherever you put it, above or below, hasn't seemed to be better one way or another.

[sivadselim]

I have my center above my TV, trust me, it's localizable if you let it.It's less localizable than it would be if it were below your TV.

[sivadselim]

I think it's fairly localizable either way, I agree. As long as it's not too far away, wherever you put it, above or below, hasn't seemed to be better one way or another.I explained why it's less localizable when above the plane of your ears than below. Granted, placing it above your TV may not necessarily place it above the plane of your ears; that would depend, ultimately, upon your TV's height.

But one need only look at the way your ears are designed to realize that their is a practical and anatomical basis for what I explained. That we are better able to localize sounds that originate from below the plane of our ears than those that originate above the plane of our ears is not arguable.

[MDS]

But one need only look at the way your ears are designed to realize that their is a practical and anatomical basis for what I explained. That we are better able to localize sounds that originate from below the plane of our ears than those that originate above the plane of our ears is not arguable.

I agree and have used the same explanation as you. However, in my experience it doesn't matter all that much unless there is a huge difference in distance between the center and mains.

[no. 5]

It's less localizable than it would be if it were below your TV.

My current entertainment center does not permit me to place the center below the TV, so I con not experiment, but I am fairly certain that any single channel will be locatable with equal ease, be it placed above the ears or not.

If you do have references to studies regarding localization, I would be interested in Reading them, as to my knowledge there is no limitation to localization due to hight of sound source.

[sivadselim]

I agree and have used the same explanation as you. However, in my experience it doesn't matter all that much unless there is a huge difference in distance between the center and mains.Yes, I would tend to agree, perhaps, but what I am describing is not simply an example of acoustic illusion or other psycho-acoustic phenomena, but, instead, has a firm basis in real anatomic structure and function.

[sivadselim]

.......................but I am fairly certain that any single channel will be locatable with equal ease, be it placed above the ears or not.

If you do have references to studies regarding localization, I would be interested in Reading them, as to my knowledge there is no limitation to localization due to hight of sound source.To your knowledge? When have you shown an interest in this subject? I'm not going to do the research for you (or maybe I will), but you're flat wrong. It surprises me that in looking in the mirror at the evolutionary design of your own ears that this would not be intuitive to you. It's almost as obvious as the reasons why we are able to localize sounds as coming from either our right or left.

http://en.wikipedia.org/wiki/Sound_localization

I would encourage you to explore the references and the external links listed at the bottom of the wiki.

:)

[no. 5]

To your knowledge? When have you shown an interest in this subject? I'm not going to do the research for you (or maybe I will), but you're flat wrong. It surprises me that in looking in the mirror at the evolutionary design of your own ears that this would not be intuitive to you. It's almost as obvious as the reasons why we are able to localize sounds as coming from either our right or left.

http://en.wikipedia.org/wiki/Sound_localization

I would encourage you to explore the references and the external links listed at the bottom of the wiki.

:)

Yes, to the extent of my knowledge of the subject, I do not recall reading a study that suggested that localization is more difficult when the sound source is above the plane of the ears, I did not ask for you to do research for me (although I do appreciate the link), I asked if you had a reference to support your supposition that sounds above the head are harder to localize.

What I was seeking was credible research or information on the subject, for a theory is well and good, and when pursued it will provides knowledge, but going no further than a theory will do no good, for a person could theorize that because our ears face forward, we are incapable of hearing behind us.

The subject of sound (and by extension therefore, psychoacoustics) is something that has captured my interest for quite a bit of time, and thus enjoy expanding my knowledge of the subject. :)

[sivadselim]

What I was seeking was credible research or information on the subject, for a theory is well and good, and when pursued it will provides knowledge, but going no further than a theory will do no good, for a person could theorize that because our ears face forward, we are incapable of hearing behind us.That's laughable. It's NOT theory. The extent of your knowledge of the subject is not so far-reaching.

How hard do you think it is for a study to prove that sounds are less localizable when they originate above the plane of your ears than below the plane of your ears? Not hard at all. That's easily testable.

And the reasons? The hypotheses are simple enough to test, as well.

And how much do you think this has been studied? Ad nauseum.

What do you think is the reason why we can hear sounds that originate in front of us better than those that originate behind us? Do you think you could devise a test that would confirm the observation that sounds that originate in front of us are easier to hear than those that originate behind us? Could you hypothesize as to why this is so? And could you devise a test to prove (or disprove) your hypothesis?

Why do you think we have 2 ears instead of 1? It's not simply because God made us that way. Are there advantages to having 2 ears on either side of your head as opposed to one single ear on your forehead? Are there advantages to having 2 ears on either side of your head as opposed to, say, one ear on the top of your head and one ear on your chin? Disadvantages? Do you think you would be able to localize vertical sounds better if you had one ear on top your head and one on your chin?

Do you think there are any ways to alter the directional cues that your ears' specific structures provide?

Jeez. You sure did a lot of research on the subject of vertical sound localization, didn't you? All you have to do is do a Google search (http://www.google.com/search?hl=en&q=vertical+sound+localization&btnG=Google+Search) to get loads of information, none of which is theory.

Yes, not surprisingly, the shape of your ear affects how you hear in nany number of ways, all proven, none theory.

http://web.media.mit.edu/~raffik/zero-g/aup/Figure2.jpg

[no. 5]

How hard do you think it is for a study to prove that sounds are less localizable when they originate above the plane of your ears than below the plane of your ears? Not hard at all. That's easily testable.

I agree, but I know of no data to support that claim, if you know of credible research, please post it.
Why do you think we have 2 ears instead of 1? It's not simply because God made us that way. Are there advantages to having 2 ears on either side of your head as opposed to one single ear on your forehead? Are there advantages to having 2 ears on either side of your head as opposed to, say, one ear on the top of your head and one ear on your chin? Disadvantages? Do you think you would be able to localize vertical sounds better if you had one ear on top your head and one on your chin?

Whoever said this had anything to do with a God? :confused:

I agree that Binaural hearing vastly improves the ability for lateral localization, but vertical localization is based on Monaural cues.
Do you think there are any ways to alter the directional cues that your ears' specific structures provide?

Of course, once enough about how a sense system functions, it is comparatively easy to devise a way to fool it.
You sure did a lot of research on the subject of vertical sound localization, didn't you? All you have to do is do a Google search (http://www.google.com/search?hl=en&q=vertical+sound+localization&btnG=Google+Search) to get loads of information, none of which is theory.

I did do several Google searches on the topic, and gained much information on the subject; such as a paper from the Air Force Research Laboratory (http://www.afrlhorizons.com/Briefs/0009/HE0002.html), that said "Humans possess a finely-tuned capability to locate the source of sounds within about 5° in elevation and azimuth" (but the paper said nothing to the effect that there is greater acuity in localization for sounds below the ears), and from the National Center for Biotechnology Information (http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=retrieve&db=pubmed&list_uids=2018391&dopt=AbstractPlus), and a paper from MIT (http://web.media.mit.edu/~raffik/zero-g/aup/linked-final.html) investigating localization in low gravity that concluded that "Localization in the vertical direction is very hard for humans to do" - but said nothing to the effect that localization is easer for sounds below the ears.
Yes, not surprisingly, the shape of your ear affects how you hear in nany number of ways, all proven, none theory.

I am well aware of that the shape of the pinna is very important in the localizing sounds.

[sivadselim]

I am well aware of that the shape of the pinna is very important in the localizing sounds.So, if you're well-aware of this, then you know exactly how the shape of the pinna affects sound localization in the medial plane.

This is not rocket science. The tests are very easy to devise. The results can be obtained in a matter of minutes. I can't find the links to the articles for you but this basic information comes from pioneering work that was done regarding sound localization begun in the 1960s.

Most anyone could simply look at the shape of the outer ear and speculate correctly as to whether it allows one to localize sounds in the medial plane that emanate from below the horizontal plane better than those that emanate from above the horizontal plane.

[AVRat]

Ray Adkins, aka RLA, installed a full Axiom setup with dual upper/lower centers. http://www.audioholics.com/reviews/speakers/floorstanding/axiom-audio-epic-80-600

[no. 5]

This is not rocket science. The tests are very easy to devise.

How do you propose such a test be devised? Should a stopwatch be sufficient to accurately quantify greater speed in location? Perhaps a friend should be used to allow the location of the sound source to remain unknown to the one being tested? What method should be employed to determine the degree of locational accuracy or error?

I ask because it is also easy to devise a test that proves that all cables sound different, if the test is to be more than anecdotal, it needs to be devised in a way that removes bias, and accurately and repeatedly produces results.
I can't find the links to the articles for you but this basic information comes from pioneering work that was done regarding sound localization begun in the 1960s.

If you find it, please post it. If you find newer research, by all means, post that too, for I'm certain that we can both agree that research into the field of human hearing perception and capability is constantly growing and being refined.
Most anyone could simply look at the shape of the outer ear and speculate correctly as to whether it allows one to localize sounds in the medial plane that emanate from below the horizontal plane better than those that emanate from above the horizontal plane.

I agree that the ear looks like it should have improved localization ability for sounds below the head than above, but the ear also looks like it should be incapable of any localization of sounds behind the head.

All I am looking for is credible research as to sound localization being more acute for sounds below the ears than for sound coming from above.

If you are aware of data that supports your theory, again, please provide it (names, places ect...), if not, this discussion is of no further usefulness to either of us.