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"Home Theater" Speakers

jhaider

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Maybe I need to explain in crystal clear detail, in case the analogy wasn't obvious enough: If Preference(2x really good speakers) > Preference(3x really bad speakers), then it's not at all far-fetched to suppose that in some cases we will find Preference(2x really good speakers) > Preference(2x really good speakers & 1 really bad center channel speaker).
While likely true, that is inconsistent with and completely out of the scope of your logical leap above concerning relative vertical placement. Never mind my original point was get the speaker placement right and adapt screen placement to that.

Regardless, it’s clear that this has devolved into a discussion between experience and idle spitballing. Experience doesn’t have any more time for it.
 
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echopraxia

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While likely true, that is inconsistent with and completely out of the scope of your logical leap above concerning relative vertical placement. Never mind my original point was get the speaker placement right and adapt screen placement to that.
Whatever your 'original point', I am merely disputing this specific statement of yours:
omitting the center channel is in my view a very stupid idea
It is not always a "very stupid idea" to omit the center channel. In many (but not all) cases, it may make more sense to omit the center channel than all viable alternates (e.g. when they all have serious disadvantages). Of course, you are welcome to disagree, and discuss your argument civilly, but on that note...
Regardless, it’s clear that this has devolved into a discussion between experience and idle spitballing. Experience doesn’t have any more time for it.
The only thing that has devolved so far is the unnecessarily hostile tone I'm seeing from you here. The rest of us, as far as I can tell, are enjoying (the civil parts of) the discussion and are learning from each other in a friendly and productive way.

You are of course welcome to participate and debate here, as long as it's civil / professional.
 
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echopraxia

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Ah sorry, I misread your post. I don't know how the SRX measurements were found for that matter, but perhaps @Speaker-Inquisitor would know how to find similar ones for the PRX if they exist.
No probs. I did try searching by same publication (and by going to model specific docs on https://www.audiopro.de/ but it takes to bonedo.de review which no measurements) but didn't find any...
The SRX835 and PRX835 comparison would also be interesting, latter being wider dispersion
 
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Tom C

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@flyzipper answered this: it’s because it would cause comb filtering, if the distances from the speakers to LP are even slightly off. Very easy to hear—have someone move one of the speakers.

Generally, pointing a copy of the same channel from 2 different speakers to the same location is avoided, unless a decorrelation algorithm is applied. This, plus other processing are what upmixers like Auro 3D Auromatic does to extract ”height” channels from existing channels. These aren’t just copies of the source.

When copy arrays are used, they are typically to fill sound over a larger area and the dispersion overlap is minimized (to avoid comb filtering), such as targeting a lower deck vs upper deck.
I’m no kind of expert in any sense. But, as you point out, there’s more than one way to do it. If I listen to mono music, either digital file or vinyl LP on my two-channel stereo, it sounds just fine. Maybe I’m just not that picky, or not that discerning. I think you’re saying one reason is that the speakers are far enough apart. Everything’s a compromise some way. What you end up choosing depends on what you want to prioritize. I’m also considering a center mounted on an adjustable height stand that could be raised to match L/R height for music listening, and lowered or raised for TV/movies.
 

Dj7675

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Is there something I'm missing, or would it be OK to angle up the center if you put it below the TV to aim it roughly at/slighty above* MLP? How to aim would depend on vertical directivity sweet spot. This is essentially what I plan on doing. I may even go with some in/on walls and do this; like Revel S16s all of the way around.

Of course this wouldn't work well with 2 row home theater, not much direct sound would get to the 2nd row. But this situation is probably pretty rare. At that point, maybe put it above and aim it down between the 2 rows for a compromise or just at the 1st row if prioritizing that row. But this seems like a strange setup to me. At that point just do it 'correctly' and use an acoustically transparent screen and put it behind it. Most home theater setups like this are probably using a projector.

Edit: With a previous system/apartment we had a TV hung on the wall. I had a shelf level with the top of the TV, put the center on it and propped the back up to angle it down. It was only a 40" TV centered about eye level so it wasn't too high. I also hid all of the network stuff and a power strip on the underside of that shelf. The TV was on a full motion mount to aim it where we wanted, move it out easily to get behind it. I put floating shelves to the right of the TV for AVR and other HT/gaming equipment.
In a home theater, LCR placement is full of compromises.. really no free lunch. I have a 122” wide 2:35 aspect ratio screen (not acoustically transparent). Room is a bit over 14 feet wide with 2 rows of seating and the second row on a 10 inch platform.
-Acoustically transparent screens aren’t necessarily transparent and will probably require some DSP to offset their affect. In addition, the gain is typically lower and will reduce brightness. Also, visibility of the holes could impact the picture depending on seating distance. I still may go this route at some point even with the trade offs because of the benefits.
-Put L/R on the edge of the 2:35 screen and center under. In my case the L/R were in the corners of the room causing them to not measure well. And because I have a 2:35 aspect ratio screen when I watched other aspect ratios such as 16:9/1:85/4:3 the L/R content was distracting as it didn’t match the action on the screen.
-Solution for me is 3 M106 on angled stands which tilt up at 6 degrees below the screen. Action on screen matches much better with all aspect ratios, sound does not appear to come from below the screen at all, and dialogue is even quite good on the second row.
It’s all about a bit of trial and error and picking the compromises you can live with. Happy with this setup, but doesn’t mean I won’t choose another set of compromises later, such as going with an acoustically transparent screen.
 
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I’m no kind of expert in any sense. But, as you point out, there’s more than one way to do it. If I listen to mono music, either digital file or vinyl LP on my two-channel stereo, it sounds just fine. Maybe I’m just not that picky, or not that discerning. I think you’re saying one reason is that the speakers are far enough apart. Everything’s a compromise some way. What you end up choosing depends on what you want to prioritize. I’m also considering a center mounted on an adjustable height stand that could be raised to match L/R height for music listening, and lowered or raised for TV/movies.
We hear it all the time when a singer is mixed to both left and right speakers so they appear in the center. How is that any different?
Yup, you're both right. Dual mono or center panned voices (same level and phase) sound fine. Our brain can filter out a lot of comb filtering issues.

An improvement is to use a center channel and mix, which eliminates comb filtering because the center sounds are coming from one source. Most perceive the improvement as enhanced clarity and speech intelligibility with the comb filtering removed.

Splitting the center channel would re-introduce the comb filtering issue.

I've personally not had a center channel because I have a 133" screen between my towers and it sounds good to me.

But with my upgrade to add height speakers (7.2.6), I'm going to add a center channel above the screen, between the left and right height speakers.
 

richard12511

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@echopraxia , given that you're going centerless and with narrow dispersion speakers, I would definitely recommend extreme toe in of the left/right speakers. Biggest downside to having no center(ime) is that the phantom center only really works well for the 1 person that's in the sweet spot. Anyone sitting to the right of the sweet spot will hear dialogue coming from the in between the screen and right speaker. Extreme toe in should help mitigate this problem somewhat.
 
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echopraxia

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@echopraxia , given that you're going centerless and with narrow dispersion speakers, I would definitely recommend extreme toe in of the left/right speakers. Biggest downside to having no center(ime) is that the phantom center only really works well for the 1 person that's in the sweet spot. Anyone sitting to the right of the sweet spot will hear dialogue coming from the in between the screen and right speaker. Extreme toe in should help mitigate this problem somewhat.
Thanks, I’ll try that. I’m not really concerned though, since they sounded surprisingly good when I tried them in just stereo, but also because my long term plan is to get a matching center once I’m ready to go with a projector screen.
 

Kvalsvoll

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Like the horizontal plane, our ability to pinpoint a sound in 3D is aided not just our processing of the sound from a fixed head position, but processing of how what we hear varies as our head moves. Once we add head rotation to the HRTF picture, perhaps you can see how we can locate a sound source vertically, even if it's frequency response is modified to 'emulate' a sound coming from lower/higher than it actually it: our ability to locate a sound by subconsciously correlating the HRTF's relative changes in frequency response as our head's pitch angle changes is an algorithm that works for any sound (of sufficient audible bandwidth), independent of that sound's frequency response. As to how obvious or subtle this is, I can't say (other than give personal anecdotes), but this clearly can't be ruled out entirely.

It's also possible that different people are attuned to horizontal and/or vertical imaging differently than others. For example, I've heard a good number of speakers over time, and not once have I ever heard a convincing ability to separate sounds in space vertically -- only horizontally, and even then, barely more than one dimension. I'm not saying speakers can't project an overall soundstage that is wide and tall; rather, I am saying that this spaciousness is usually achieved uniformly, not in a way that allows one instrument to be placed really 'high altitude' while another is simultaneously really 'low altitude'.
Exactly, thank you for pointing out.

When we move the head, we "remember" the location, it is kind of revealed, and stick with us even when we stop moving. But sensitivity is not very good, so a center right above or below the screen, may pass.

I believe sense of height placement in the soundstage is learned, which implies the perception will be different from person to person.
 
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Never mind my original point was get the speaker placement right and adapt screen placement to that.
I understand your preference for audio, as a music-first person, but you've come into a thread titled "Home Theater" Speakers, so telling people to move their screens is like walking into a Country Music bar and telling everyone to remove their funny hats and pointy boots.
...get the center placed aligned with the left and right speakers...
I also agree 100% that the ideal LCR speaker placement is with each channel aligned.
To the extent that your alleged “vertical imaging shift” is actually a thing, it is driven by a visual cue of seeing the low loudspeaker as discussed earlier.
This is where the rub is.

It's simply not true that visual cues are the only reason for sound differences when the centre channel is placed below alignment with the L & R speakers.

The room matters, and speaker placement in the room matters.

That's why speakers are tested in anechoic chambers, or using consistent measurement practices (Amir spent $100K on his speaker test rig to counter this reality). Otherwise, the same speaker can measure and sound very differently depending on the environment and its placement within.

Anecdotally, I've set up two home theatre systems (5.1 and 7.1) using identical speakers for all channels. My experience in those cases, when using the tone generator to set levels... each speaker sounds slightly different. Same speaker, same room, same tone... different placements, and different listener orientation to the placements.

In my room, the 1st reflection point of the LCR channels is the floor, so placing the centre channel closer to the floor to accommodate a TV screen reinforces that boundary effect, even with high quality 3 timbre matched speakers. The direct sound is only shifted slightly with the lower placement, but consider how the reflections are changed.

And for the record I called nobody dumb, but omitting the center channel is in my view a very stupid idea.
Regardless, it’s clear that this has devolved into a discussion between experience and idle spitballing. Experience doesn’t have any more time for it.
Here's the other rub... I'm sure you didn't intend ill with these statements, but they're still ad hominems.

This dummy wishes you well.
 
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