[SayersWeb]

Someone just posted in the Front Projector forum that they are installing a front projection system where the screen will be close to the ceiling with just enough room above it for the center channel. I questioned why they were placing the center channel above the screen since this would mean their left and right channel speakers will also need to be placed this high so that the tweeters will be at the same height. The reply was that it is general concensus on the HT Builder forum that if you cannot place the center behind the screen that it should be above.


This would make sense to me for an RPTV, but for a projection screen mounted near the ceiling? I've heard systems like this and the sound placement seems too high. Especially if the left and right channels are also placed at the same level.


I've recently finished a rather non-intrusive HT install in my home. As you can see from the picture the center is close to level with the tweeters on the main speakers. They are below the screen and the resulting sound is fantastic.
http://www.sayersweb.com/home_theate...3-02-16_01.jpg


So, I'm just curious.... I understand that my speakers are not in-wall and I don't have multi-row seating. Does this make a difference? I get questions from friends/co-workers about this kind of thing occassionally and want to make sure I share the correct information.


More info on my setup can be found here .


Thanks!

 

[robertmee]

For your setup, I would have placed the center speaker below too. However, not to be rude, but your screen seems too high. From a seated position, most recommend that a parallel (to the floor) sightline is around the bottom 1/3 of the screen. Judging from your picture, your sightline from seating would be below the screen.


The reason many recommend putting the center speaker above the screen is because of the human's ability to localize sounds. We as hunters and gatherers were atuned to finding our prey on the ground, not up in the air. Our predators largely were earthbound as well, so through years of evolution, our ears became astute at localizing sound below the horizon of our eyes, while we have difficulty above. With the center channel below, dialogue will sound like it is coming from the speaker, whereas with the speaker above, dialog will sound like it comes from the screen, because we aren't so apt to pinpoint it.

 

[SayersWeb]

Quote:

Originally posted by robertmee For your setup, I would have placed the center speaker below too. However, not to be rude, but your screen seems too high. From a seated position, most recommend that a parallel (to the floor) sightline is around the bottom 1/3 of the screen. Judging from your picture, your sightline from seating would be below the screen.

I struggled with screen height when planning my system. The tradeoff was to raise it above the speaker tops, move the speakers out very wide, or shrink the screen. In the end after many test trials I went with the higher and larger screen.


The bottom of the screen is at about eye level. I was worried this would be bothersome, but it is quite comfortable and natural. We've had about 20 people view full movies on the screen since installing and no one has found it to be an issue. I typically let people watch a movie and then afterwards ask them questions about the sound, video, screen, comfort, etc. Not one found an issue with the screen height when asked. Several of them are quite discerning when it comes to this kind of thing and I was a bit surprised. I'm not saying it is perfect, but it was not worth the tradeoffs to lower the screen 12".

Quote:

Originally posted by robertmee The reason many recommend putting the center speaker above the screen is because of the human's ability to localize sounds. We as hunters and gatherers were atuned to finding our prey on the ground, not up in the air. Our predators largely were earthbound as well, so through years of evolution, our ears became astute at localizing sound below the horizon of our eyes, while we have difficulty above. With the center channel below, dialogue will sound like it is coming from the speaker, whereas with the speaker above, dialog will sound like it comes from the screen, because we aren't so apt to pinpoint it.

Those are some interesting ideas. Of course, I want my front and center channels to be somewhat directional. That's what makes up a good soundstage. Maybe it's because I have a music studio and focus more attention on the sound aspect. To me, a center channel near the ceiling still sounds like it is near the ceiling, but it does sound more diffuse and less clear. This seems to make the dialogue harder to understand. The center channel will always be directional since it contains a tweeter which produces high frequencies. IMHO it really should be as close to ear level as possible so that it doesn't sound like the actors are talking from the ceiling. Again, maybe it's because I work with music that I find it bothersome.


I hope that people who do put the center channel above the screen also place their left and right channels at the same height. Otherwise, when you have a movie sound effect like a car driving by from left to right the sound jumps to the ceiling while in the center channel. This can be distracting to the point of taking attention away from the movie. This is especially true with high frequencies. Your tweeters between the front three speakers should always be as close to the same height as possible. I always find it amusing when I go into the HT shops and see this triangular front channel configuration.

 

[mbrandt]

SayersWeb -


Sorry to hijack the thread from its original topic, but I noticed that you have an ATI 2505 powering your speakers. I currently have a 1505 and have been thinking of upgrading to the 2505. Can I ask you two questions?


- Are you feeding that beast on a 20 amp electrical line?

- What do you think of it?


To chime in on the original topic - tweeter height is best when their level across the front (preferably with the same exact type of speaker). It's the only way to have sound pan across convincingly. Sayer - you actually have space there for an identical center. Did you have trouble finding a single Kappa 8?


Thanks -


Mark

 

[SayersWeb]

Quote:

Originally posted by mbrandt SayersWeb - Sorry to hijack the thread from its original topic, but I noticed that you have an ATI 2505 powering your speakers. I currently have a 1505 and have been thinking of upgrading to the 2505. Can I ask you two questions? - Are you feeding that beast on a 20 amp electrical line? - What do you think of it?

Hi Mark,


I have a 20 amp outlet, but on a 15 amp circuit. I had an electrician in and he didn't think it was necassary to upgrade the circuit. At first I was still going to upgrade, but at this point it sounds so good that I may not bother.


The amp is absolutely fantastic. It really excels in unstrained dynamic range. The loud passages in a movie are very big sounding but at the same time very smooth. No harshness and it never feels that the sound has hit the dynamic range ceiling where everything starts to sound muddy and forced. The quiet passages in a movie are clear and full sounding. Dialogue is clear and natural.


I was very close to replacing all 5 Infinity Kappas in my HT until I got the ATI 2505 amp and the Rotel RSP-1066 pre/pro. This combination opened up the sound of the Kappas and gave them new life. I went from underwhelmed to overjoyed with the sound. I'm quite pleased with both music and movie soundtracks.

Quote:

Originally posted by mbrandt To chime in on the original topic - tweeter height is best when their level across the front (preferably with the same exact type of speaker). It's the only way to have sound pan across convincingly. Sayer - you actually have space there for an identical center. Did you have trouble finding a single Kappa 8?

Arghh! Now you're being a bad influence!!


I looked around a bit for another Kappa 8... but it never would have passed the WAF (Wife Acceptance Factor) test. I had already pushed my luck by going with a front projector instead of an RPTV (It took weeks to convince her... she now loves the front projector and is so happy we went that route). My concession was to let her get a small oak bookcase to put the center channel on to give the room a more finished look. So, another tower speaker was out of the question.


The Kappa center is perfectly matched except for the low frequencies which roll off higher than the mains. It requires the subwoofer crossover on the RSP-1066 to be set a bit higher, but sounds quite good. I would love to have an indentical center though.....

 

[mbrandt]

Sayer -


The only reason I mentioned going with Kappa's all across the front is because I've recently seen a few 8's for sale by their owners over at audiogon. Don't know if they're still there.


Thanks for your opinion on the 2505. I've just heard stellar things about it and would be hooking it up to its own 20 amp line. The only thing holding me back is my wife as well. Ahhh, the concessions we make...


Front projection makes sense, especially in regards to WAF. Screens don't look like huge black boxes that stick almost three feet out into the room, dominating the space. Plus, there's no comparison when it comes to picture quality.


- Mark

 

[robertmee]

Quote:

Originally posted by SayersWeb IMHO it really should be as close to ear level as possible so that it doesn't sound like the actors are talking from the ceiling. Again, maybe it's because I work with music that I find it bothersome. I hope that people who do put the center channel above the screen also place their left and right channels at the same height. Otherwise, when you have a movie sound effect like a car driving by from left to right the sound jumps to the ceiling while in the center channel. This can be distracting to the point of taking attention away from the movie. This is especially true with high frequencies. Your tweeters between the front three speakers should always be as close to the same height as possible. I always find it amusing when I go into the HT shops and see this triangular front channel configuration.

I absolutely agree. In a perfect setup, we would all have perforated screens such that our speaker's F/C/R tweeters were all aligned, and the center channel would be behind the screen. However, most of us don't have $$$ to spend on perforated screens, so we begin to make compromises. If you are unable to align your speaker's tweeters, then the second best option is placing the speaker above the screen, and elevating the L/R tweeters a bit to get them close. I'm not advocating sticking your L/R on the ceiling as that would cause many more problems. If you put your center on the bottom, then you could turn your L/R upside down, but again that would just make all the sound effects seem like they are coming from the floor. That's why, based on your screen position, acoustically you did the right thing in that all your tweeters are aligned. If the video experience is not compromised by having the screen a bit high, then your setup is the perfect compromise.

 

[Dennis Erskine]

DO NOT turn your L/R speakers upside down!

 

[SayersWeb]

Quote:

Originally posted by Dennis Erskine DO NOT turn your L/R speakers upside down!

I agreee.... If you must put your center channel above the screen then your right and left mains should probably be an identical speaker as the center. Then you can orient them properly....


Although all of the sound will be coming from the ceiling!

 

[robertmee]

Quote:

Originally posted by Dennis Erskine DO NOT turn your L/R speakers upside down!

That was my point in not putting the center channel below....Maybe next time I should include some rolleyes

 

[damon]

I hate the idea of a high-end display having to make do with the

limitations of a perforated screen. Why have I never seen a cost no object setup with a center channel speakers above & below the screen on axis to meet at a predescribed point in the room?


just wondering, damon

 

[Dennis Erskine]

What do think the limitations of a properly perforated screen is on the display?


If you have the same signal coming from two speakers (as in your 'why haven't I" question), the result will be significant intermodulation distortion, tremendous phase coherence issues and an long list of other nasties.

 

[Glimmie]

Quote:

Originally posted by Dennis Erskine What do think the limitations of a properly perforated screen is on the display?

Well the two most known are potential morie and light loss, the latter being very minor. The morie issue can be predicted mathmatically if anyone cares to sit down and do the math and know all you dimensions and focal legnths. Both Stewart and Dalite caution buyers of perforated screens about the morie issue.


Most will agree there are very little acoustical problems with the center behind the screen.


I thought long and hard as where to put my center. I do have clearance behind the screen and could have gone that way. In the end I am placing it under the screen but firing at an angle to the viewers ears. This speaker cradle behind the grill fabric is adjustable. I have five 19in VGA monitors in a bridge above the screen so it was either behind or below.


FWEIW, professional screening rooms and general theaters all have speakers behind the screen. It is the accepted proper way to go at least for film projection.

 

[Dennis Erskine]

With a digital projector, losing 10% (such as going from 19 ft lamberts down to 17.1) is a blessing and reduces the need to watch movies with your sunglasses on. If you're at 8 ft lamberts, going down to 7.2 is a non-starter and you've too big a screen to begin with.


As was stated, morie can be predicted, can be resolved and affects only pixel based projectors.


Aiming a low speaker up at the seating position exacerbates the localization problem but resolves the off axis issue.


None-the-less, even in a "cost no object" project, there will be compromises along the way.

 

[Glimmie]

Quote:

Originally posted by Dennis Erskine Aiming a low speaker up at the seating position exacerbates the localization problem but resolves the off axis issue.

So bad idea? Is there a good angle to position the center at?

 

[SayersWeb]

Hmmm... After all of these comments, I think I may have gotten lucky and ended up with the best compromise between audio and video performance.


My screen is a little bit high, but seems quite acceptable to everyone that has viewed it. I actually forgot about the whole screen being to high worries that I had during setup until it was mentioned above... It's just doesn't seem to be an issue with where it is placed.


The audio is also positioned well for both movies and stereo music. It sounds incredible.


I guess each of us has to to choose the tradeoffs depending on their own preferences of sound versus video. But, please don't discount the importance of sound placement too much. It plays a big part in how immersive the experience is.


Oh, and speaking of immersive.... I have a bass shaker attached to the frame of my HT couch. When adjusted properly (not to high) it really adds to the experience. I bought a set off Ebay for a very good price. they came with their own amps.