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Post by fbczar on Mar 21, 2016 17:58:20 GMT -5
Chuckienut, Thanks for taking the time to post your reply. I remember the Advents well and heard them is stereo shops many times, but have never talked with an owner. I have often heard a vertical center channel configuration was better than a horizontal one, but most setups, like mine, could not work with a vertical speaker as a center channel. Fortunately Dirac seems to have a positive effect on bringing the sound of disparate speakers together in a home theater system. Obviously, the closer you can match the better.
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Post by albertiwell on Mar 21, 2016 19:22:12 GMT -5
I always thought that the best central speaker is the same as L&R ones. The problem is that this is not possible if you don't have a dedicated home theatre room, but a living, and sharing the gear with the TV.
I´m curious about the result, both, 2 center speakers above and below the screen, or two speakers both sides of the tv screen for the centre channel.
Second option, toeing the speakers to the sweet spot, will allow me to use the second pair of floor-standing speakers that now i have for sale. I will put them both sides of the 55"plasma TV, and maybe i will obtain deep bass and solid centre channel, and when i´ll use the acoustical transparent 120"screen, the sound will still come from the centre without having to change the position of them. In addition, the tweeters of the centre channel will stay at the perfect height both for TV and PY.
This weekend i will start to make tests. Maybe i have found the solution to the problem i always found with d´apolito central speakers, lack of consistency.
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Post by Boomzilla on Mar 21, 2016 20:55:37 GMT -5
Since I already have stands, my "dual center" speakers will reside on either side of the screen, giving a "phantom center" from the screen's middle. That makes more rack room for the equipment. THANK YOU to all who have replied to this thread - I've learned some new things and now have lots more to think about.
Boomzilla
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Post by Deleted on Mar 22, 2016 0:47:24 GMT -5
I always thought that the best central speaker is the same as L&R ones. The problem is that this is not possible if you don't have a dedicated home theatre room, but a living, and sharing the gear with the TV.I´m curious about the result, both, 2 center speakers above and below the screen, or two speakers both sides of the tv screen for the centre channel. Second option, toeing the speakers to the sweet spot, will allow me to use the second pair of floor-standing speakers that now i have for sale. I will put them both sides of the 55"plasma TV, and maybe i will obtain deep bass and solid centre channel, and when i´ll use the acoustical transparent 120"screen, the sound will still come from the centre without having to change the position of them. In addition, the tweeters of the centre channel will stay at the perfect height both for TV and PY. This weekend i will start to make tests. Maybe i have found the solution to the problem i always found with d´apolito central speakers, lack of consistency. If it were possible then yes the exact same speaker would be ideal. However, that is not practical in almost all cases. What many brands do is to make a center speaker that is essentially a small version of the L&R without the low end. The low bass is correctly re-directed to the sub in the bass management. Klispch does exactly that in your RP-450C which is designed to sit horizontally and closely match the sound/timbre of your RP-280F towers (they both have the same horn tweeter). I see you also have the RP-250S surrrounds. What a great job matching the speakers plus a great choice in the XPA-5, XMC-1 and your two powerful SVS subs. You have one awesome system there. This might surprise you but even with the fairly low end on the towers I would cross them over (set as "small") at about 60-70Hz and cross the center over (set as "small") at about 80Hz. This re-directs the low bass below the crossover point and combines it with the LFE channel bass and sends them together to the subs. I'm not sure why you have any issues with the center speaker? If your screen is 16:9, then it should be about 74.5" tall and if it is 2.35:1 it should be about 58" tall and I think you might have room both above and below the screen for the center speaker. The Klipsch center RP-450C is about 6.8" tall. Is there any reason you can't mount the center Klipsch (titled up) on a very short stand just below the screen or mounted on the wall (tilted down) just above the screen? This would be the ideal location for the speakers you have. If for some reason this is not possible then I would first try having a phantom center from the two towers.Sorry, I just see that I was looking at your signature and missed that you have both a plasma and a screen. First of all, forget about the deep bass from the center channel. The bass management will take care of it as it will be re-directed to the subs from 80Hz and down, no problem there. I would mount the RP-450C either just below or above the plasma screen. Try to get it as close to the height of the tower tweeters if possible. Otherwise shim or tilt the center speaker slightly up or down if desired. This should make a very nice LCR blend with the L&R towers. Many times it is possible with such a large/strong center speaker to actually set the plasma right on the center speaker with some padding. I would forget any idea of using the extra floorstanding speakers as side center speakers ...... bad idea IMO!
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geebo
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Post by geebo on Mar 22, 2016 6:46:25 GMT -5
Since I already have stands, my "dual center" speakers will reside on either side of the screen, giving a "phantom center" from the screen's middle. That makes more rack room for the equipment. THANK YOU to all who have replied to this thread - I've learned some new things and now have lots more to think about. Boomzilla It'll only create a phantom center for those seated between the two "center" speakers. If someone is off to one side they will hear dialog coming from that side of the screen.
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Post by Boomzilla on Mar 22, 2016 8:01:02 GMT -5
True - but they WILL have a center channel feed that will make the dialogue clear.
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Post by KeithL on Mar 22, 2016 9:30:52 GMT -5
Yes, that's true - but remember that, if you tell your pre/pro or AVR that you don't have a center, then it will send the center channel dialog information to the front left and front right, which will still play it (as a "phantom center channel"); it's not just throwing away the information that belongs in the center. The other thing to remember is that the term "phantom center" is a bit of a misnomer. Start with actual reality - a singer standing center stage - and you sitting front row center. Their voice reaches your two ears at the same time, and there's a very high percentage of direct sound compared to reflected sound. The direct sound comes to you from a short distance, and the sound reflected from the walls and the rear wall has a significant delay. Also, if the room is symmetrical, then all the delays and signal paths are also symmetrical. Obviously, if you play that singer's voice through a single center speaker, then the sound patterns will be the same as well. Now, let's look at two front speakers in a stereo configuration instead. Now, instead of coming from directly in front of you, the singer's voice is coming at you from TWO sources, each about 45 degrees off axis - to the right and left. The sound coming from the left front speaker (to your left) reaches the left ear first, barely having to wrap around your head at all, while it reaches your right ear about one millisecond later after wrapping around your head. The sound coming from the right front speaker (to your right) reaches the right ear first, barely having to wrap around your head at all, while it reaches your left ear about one millisecond later after wrapping around your head. As you can see, the arrival times are spread out by a few milliseconds. However, since each side speaker is nearer to the side wall that the center source, there is also a higher percentage of sound reaching your ears after being reflected off a side wall. This is all a bit different than what happens with a single center source. Now let's look what happens if you move OFF CENTER. With a real center source, as you move to the left or right, the sound that originates in the center speaker "pulls" towards the center. No matter which way YOU move, the sound is still coming to you from the direction of a point in the center of the stage. But, with two speakers and a "phantom center", the exact opposite is true; as you move to one side, a greater proportion of the "center" content reaches you from that side, and less from the other side, so, as you move to one side, the image shifts towards that side even further than you moved. (So, if you move to the left, instead of the singer now sounding like he or she is to your right, which is where the actual physical center of the stage is, they sound like they're FAR TO YOUR LEFT... because you've moved closer to the left speaker, which is now proportionally louder.) So, with a phantom center, when you move to the left or right, the sound seems to move in the OPPOSITE direction than it naturally would with a real sound source. This is why "phantom images" work very well if you're positioned correctly, but not so well if you're not in the proper location. Now, if you use a pair of speakers for your center channel, located on either side of the screen, you have a "phantom center center". Since they aren't being fed from two separate "center-l and center-r" channels, you have the same signal coming from two speakers located some distance apart. Therefore, you're going to have a horizontal comb filter effect being applied to whatever signal is played equally through both of them.... which is going to complicate things even more. You're also going to have a center source that seems wider than if it was a single speaker - because it is. Note that all of this analysis is theoretical, and in certain rooms, with certain speakers and certain content, dual centers, or a phantom center, can in fact work very well. The point is that it may or may not work well in your specific system... and you may have to try different ways of arranging things, like applying a drastic toe-in to those dual center speakers, or adjusting the level to something other than what you might expect, in order to get it all to work together. I would also suggest that, if you're planning to use dual centers, you're probably better off with a less live room, and with speakers with relatively narrower dispersion.... because that will give you more direct sound, and a less complex pattern of overlapping room reflections from all those speakers to "complicate" the sound image. True - but they WILL have a center channel feed that will make the dialogue clear.
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Post by Boomzilla on Mar 22, 2016 11:19:57 GMT -5
Hi Mr. L!
You're absolutely right. A single center source, placed in the direct center of the screen would be best. But for most of us, it just isn't practical. The only way to do it would be to use a front-projection rig with an acoustically transparent screen.
So no matter what a home user does, there WILL be some compromise. The least compromised option would be to use a single point-source radiator either above or below the screen. This is what most "center channel" speakers are intended for. But if that option is not feasible, the next best thing would be to use speakers either above / below the screen or to use speakers as close as possible to either side of the screen.
Note that ALL of these options (even the "ideal - speaker-in-the-middle-of-the-screen") WILL introduce comb filtering between the right and left main speakers. Since comb filtering is inevitable, just throw it out completely as a consideration. You can't prevent it, so just live with it.
The goal should be to get as much center channel direct sound to the viewer as possible. So either a single speaker above or below / a pair of speakers above or below / or a pair of speakers on either side of the screen should all suffice. I'm going to try the KeithL option of one on either side, toed in to 45 degree angles. I'll let y'all know how it works!
Boom
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Post by Deleted on Mar 22, 2016 11:35:40 GMT -5
So your saying that every commercial theater suffers from comb filtering??
Can you please point me to prof of this (not being a jerk, I really want to read about this as its exact he I have my setup behind a AT screen)
Thanks
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Post by KeithL on Mar 22, 2016 12:05:14 GMT -5
Comb filtering is simply a matter of physics..... if you have waves originating from two or more sources, they WILL produce interference patterns (a patterns of points in space where the signals add and subtract). You could ask the same question about nodes and nulls..... EVERY room has room modes, which have nodes (where the sound waves add) and nulls (where they cancel out). EVERY room, except an anechoic chamber or an open field, has them, and you can calculate what frequencies they will occur at simply based on the dimensions of the room (for each room dimension, every frequency with a wavelength that is a multiple of that dimension will react with it, to some degree). But the more important questions are whether several of them occur at the same frequency - which would be bad, how bad each one is, and where the nulls and nodes end up for each one. In the case of comb filtering, the important question is whether it will be audible or not.... and if it will be audible at frequencies we are especially sensitive to. Human hearing is especially sensitive to midrange frequencies. And, with the distance between drivers in center channel speakers, or between two midrange drivers on speakers set next to each other, it's not at all unusual for comb filter effects at midrange frequencies to be on the order of six inches to a foot apart. This means that, for example, if you play a steady 750 Hz tone, and move your head to the left and right, the tone might get noticeably louder and quieter every six inches or so you move.... which is audibly quite annoying. In general, as you get speakers more than a few feet apart, the comb filter effects at midrange frequencies get less distinct, and so less annoying. For an interesting experiment, simply play a steady test tone - like a middle C - out of one speaker (at a reasonably quiet level). Now move your head carefully up and down and back and forth. Notice how the level isn't absolutely steady. What you're hearing is cancellations and additions (interference) between the tone coming directly from the speaker and reflections from various walls and other objects. Since crossovers aren't absolutely sharp, you may also be hearing interference between the tone coming from two drivers in the speaker you're using. Now try the same experiment, only play the same tone in mono from two separate speakers. (You will note that, proportionately, as the speakers are moved closer together, the patterns tend to get wider and more distinct; and, as the speakers are mover further apart, the patterns tend to be gentler.) Try different frequencies and you'll notice that the results are similar, but different in terms of location and spacing. So your saying that every commercial theater suffers from comb filtering?? Can you please point me to prof of this (not being a jerk, I really want to read about this as its exact he I have my setup behind a AT screen) Thanks
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Post by smarties on Mar 22, 2016 14:40:38 GMT -5
Just go mono, problem solved lol
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