Speaker placement with a 120" screen

**zacjones** · 02 April 2011, 14:56 Saturday

The CLD dynamic series in an in-wall version would be another option. that would effectively push the speakers back another 30" and probably allow the mains to be placed just outside the screen. Probably. I'd hate to build them into the walls and find they don't image well from there.

**madmac** · 03 April 2011, 09:55 Sunday

I think speaker placement under a screen of that size is the only option really. I have concerns as to how close you are planning on sitting in front of the screen. The closer you are, the more defects you will see in the picture. Being a projector tv, you will have to be in a completely dark room. Using all center channel speakers is an interesting option. I use center channel speakers for each of my surrounds as well as my center and they work well. Are the speakers going to be used only for TV and home theatre?.

**Chris D** · 03 April 2011, 13:48 Sunday

Yes, a problem to some degree or another when you get a large screen. Personal preference, in part. I would prefer (and use in my current theater) putting the mains on the side, even if they're wide, and the center above or below, whichever is better. HOWEVER, I believe the ultimately ideal answer is to get an acoustically transparent screen, and place all three front speakers BEHIND the screen, at the appropriate point in space. I used this in my previous theater.

**zacjones** · 03 April 2011, 16:08 Sunday

Thanks for the replies.

MadMac - I'm in the market for a 1080p projector. I might see a little pixelization at 12' with a 120" screen, but I'm thinking it won't be too bad, as that's right on the cusp of pixelization according to the charts I've looked at. I understand that using the three center channels or any lineup of speakers under the screen will be seriously detrimental to listening to two channel music. I'm not to happy about that part of it, but it's something I could live with if the theater sound came together very nicely. I could always build some towers with the MTM at standing eye level and use them outside the screen area for the Denon front height surround and two channel listening!

Chris - I think a good place to start would be to move my surrounds to below the screen and hook them up as mains. I could also A/B the surrounds placed under the screen vs the towers placed outside the screen. I'm also going to do some research to see how the Statements and Dynamic series perform off-axis, in both the vertical and horizontal domains, considering both the mains and the center channels for L/C/R's. I'm also with you on having the speakers outside the screen area -- I like the big soundstage that can provide. I'm just not getting the imaging I want because the speakers are too far forward. I'm really starting to think the ideal setup would be the Dynamic 4T series in-wall version placed outside the screen, and the center channel below the screen. This would put the front speaker baffles about 10' apart, and at about 12.5' forward of the listener. That's a significantly better ratio than I'm currently running, and I think it would be enough.

I'm going to have to email Jed again over at Clearwave to see what he thinks. There are other boundary issues that are more easily explained with pictures, so I'll post some photos of the room and setup tomorrow.

Thanks again for your thoughts.

**George Bellefontaine** · 05 April 2011, 10:11 Tuesday

I have a 105" screen and my left, right and center speakers are all mounted under the screen frame, slightly angled upward. It works just fine in my room.

**wettou** · 06 April 2011, 00:39 Wednesday

I have a 10 foot wide screen and have right underneath the B&W 800Diamonds and 802D works great.

I sit about ten feet away from the screen and speakers :T

**madmac** · 06 April 2011, 09:20 Wednesday

Originally posted by wettou

I have a 10 foot wide screen and have right underneath the B&W 800Diamonds and 802D works great.

I sit about ten feet away from the screen and speakers :T

How is the picture at a 10ft sitting distance in your case?. Are you seeing any artifacts?. Dvd quality on a screen of that size must be a problem no??.

I am a big fan and big believer in putting the center channel below rather than above screens where possible. The sound thins out too much if placed above.

**zacjones** · 07 April 2011, 03:21 Thursday

Everyone's asleep and I had to sneak around, so the photos didn't turn out well. At least you can get an idea. The photos were taken from outside the room through the openings on the back wall. The google sketchup shots give you a better idea of the layout...

This is the best room layout I could come up with. Next time we watch a movie it'll be with the bookshelf speakers propped up to just below the screen level, and the mains as surrounds.

You see the 50" plasma front and center. We're still holding out for a projector -- my dad's got an old 720p BenQ we will soon be borrowing until next year's models come out. PTAE5000u maybe? So I can't comment on 1080p picture quality and pixelization from the 12' viewing distance. I think it's going to be OK though.

So you see there is sufficient space for the speakers on the sides of the screen, 2' on the L side and 3' on the R side before the recess pops out. The problem is really the relatively short distance to the listening plane of the sofa from the baffle plane of the speakers.

Any ideas as to what might be the ideal L/C/R setup for under the screen performance:

(A) three horizontal center channels
(B) two bookshelf speakers and a center channel
(C) three bookshelf speakers

Then there's the possibility of a Line Array speaker like those at Rick Craig's site Selah Audio. Those are supposed to have very good horizontal dispersion, and might work very well as mains outside the screen.

I repeat. Fixed screen is out. New AT screen NOT approved.

:

Thanks. Zac.

**madmac** · 07 April 2011, 08:58 Thursday

Originally posted by zacjones

Everyone's asleep and I had to sneak around, so the photos didn't turn out well. At least you can get an idea. The photos were taken from outside the room through the openings on the back wall. The google sketchup shots give you a better idea of the layout...

This is the best room layout I could come up with. Next time we watch a movie it'll be with the bookshelf speakers propped up to just below the screen level, and the mains as surrounds.

You see the 50" plasma front and center. We're still holding out for a projector -- my dad's got an old 720p BenQ we will soon be borrowing until next year's models come out. PTAE5000u maybe? So I can't comment on 1080p picture quality and pixelization from the 12' viewing distance. I think it's going to be OK though.

So you see there is sufficient space for the speakers on the sides of the screen, 2' on the L side and 3' on the R side before the recess pops out. The problem is really the relatively short distance to the listening plane of the sofa from the baffle plane of the speakers.

Any ideas as to what might be the ideal L/C/R setup for under the screen performance:

(A) three horizontal center channels
(B) two bookshelf speakers and a center channel
(C) three bookshelf speakers

Then there's the possibility of a Line Array speaker like those at Rick Craig's site Selah Audio. Those are supposed to have very good horizontal dispersion, and might work very well as mains outside the screen.

I repeat. Fixed screen is out. New AT screen NOT approved.

:

Thanks. Zac.

The single most important thing in speaker selection for HT is that they be all the same. Meaning, they all are by the same mfr and model series and use the same driver composition. This is really important for the sound to come together as a whole both for music and Home theatre.

What in heaven's name is that HUGE box with the mega driver?. Is that thing your sub??!!! Jezzus !!! 8O

**zacjones** · 07 April 2011, 14:57 Thursday

Yep those are two subs I built with Mach5 IXL 18.4 drivers. I have yet to test them with a WT3 or any measurement software, but one is designed to be 9.5cf tuned to 20.5hz and the other 12cf tuned to 16.5hz. I'm currently running just the one 20.5hz sub because it's easy to protect that speaker with the DCX2496 at it's lowest SSF setting of 20hz. I've already blown one driver in the other box because I didn't have a SSF on it. Fitting that the sub croaked during Live Free and Die Hard ! :E Oh well a recone kit is $100 from Mach5Audio. Could have been worse that's for sure.

**madmac** · 08 April 2011, 09:12 Friday

As far as I can see with the drop down projection screen, you should have no problem putting for main speakers on the sides of it. It's big, but not that big. Your speaker separation would not be excessive. I'm not sure placing your center channel speaker on top of the sub is such a great idea however. But at the end of the day, so long as your happy with the sound that is all that matters!!.

**zacjones** · 09 April 2011, 13:13 Saturday

It might not look like it from the pictures, but the speakers seem pretty far apart in person. I'd have to measure again, but I think they are roughly 9.5' apart. I've been told the ideal ratio is 1 to 1.5 so instead of the listener being the recommended 14.25' feet back from the baffles, the listener is at approximately 9.5'. Depending on how close we can tolerate sitting to the 120" screen I'd also like to consider moving the sofa one or two feet off the back wall, up to a 10' or 11' viewing distance, and 7.5' to 8.5' baffle distance. That would make the ratio even worse with the mains outside the screen. There is a projector demo room not too far away. I need to go down there and do some sampling of screen sizes and viewing distances with a 1080p projector, determine where I'm going to put the sofa, and go from there. I also need to pick up some owens corning fiberglass panels and prop them up on the side walls, behind the speakers, and behind the listeners between the windows to aid in determining speaker placement. I'm also considering raising the sofa onto a platform so that the back of the sofa is above the bottom ledge of the window, minimizing rear wall reflections.

Thanks for your help, it helps to talk these things out.

I agree the sub there is far from ideal, but it's only temporary, as I sold the TV stand, and it looks a lot better than the alternatives I have in the garage. I've got to figure out where in the floor the two IB manifolds are going to go. More importantly, I've got to figure out where I'm putting the mains and center channel. Whatever floor space is left I can consider for IB placements. Next up is removing the plasma tv and the sub/tv stand/center channel stand, and placing the sofa, mains and center channel where they are going to reside, and building two simple sealed enclosures for those 18's for testing and measuring for the IB manifold locations.

**madmac** · 10 April 2011, 10:13 Sunday

I don't really buy into the 1 to 1.5 rule on the whole. With some speakers, more separation sounds better. Use your ears as a guide rather than 'rules' .For HT applications, the issue is moot since you have a center channel speaker in the middle.

**zacjones** · 10 April 2011, 23:08 Sunday

Yes I'm seeing that on the Seymour AV site as well. According to them, the recommended speaker angle is 22 to 30 degrees from center. That would mean that if the speakers are 9.5' apart then I should be sitting back somewhere between 8.25' to 9.5'. I guess I must be thinking of a 2-channel ratio of 1 to 1.5.

OK so I guess I'll play with screen height and center channel height to try and get the center channel better integrated with the mains. If I raised the screen housing to the ceiling I could move the center up another six inches. That'd get the tweeter a lot closer to being on plane with the mains. I could then build the sofa onto a riser to get me closer to ear level on the tweeters and eye level on the screen.

I think I'd better push the TV against the back wall and hand truck those subs out of there for a while too while I try and sort out placement. They've got to be causing some significant boundary issues. I've got a couple speaker stands I can use for the center channel that are much more acoustically insignificant than that sub there.

The primary IB positions I'm thinking of would be between the center and the mains.

And eventually an AT screen would then drop down in front of the speakers, at the appropriate viewing height.

Thanks. Zac.

**zacjones** · 10 April 2011, 23:47 Sunday

Maybe before I start messing with screen height and risers I'll just try angling the center up a little. I haven't tried that yet. Also I'll need to pick up some acoustic panels and play around with them. It's possible that these changes alone may improve things to where I'm happy with the setup.

**madmac** · 11 April 2011, 08:44 Monday

Originally posted by zacjones

Maybe before I start messing with screen height and risers I'll just try angling the center up a little. I haven't tried that yet. Also I'll need to pick up some acoustic panels and play around with them. It's possible that these changes alone may improve things to where I'm happy with the setup.

My center channel is identical to my mains in model# series and driver composition. I have my center lower than my mains (It's hard not to with a TV in the way!!) and I have it angled slightly up to fire towards the listeners. The center is free standing on a stand away from the back wall however with no borders beside it. All three fronts are set to small with a 80hz cutoff to the sub. The sound is 'seamless' to my ears.......even with music played in 5ch Stereo :T

**zacjones** · 14 April 2011, 16:30 Thursday

Well, never say never. We found a good deal on an AT screen and are going to go ahead with it. As always, Jed at Clearwave delivers with a shallower version of a sealed Dynamic 4T with a compensated crossover design that will allow placement of the sealed L/C/R towers all the way against the fully acoustically treated recess wall and sides (2" OC703), allowing placement of the AT screen as far back as possible, providing the greatest viewing and listening distance at the seated positions. Problem solved!

**Chris D** · 15 April 2011, 11:44 Friday

Outstanding! Another HT success story! That definitely deserves a banana. :banana:

**zacjones** · 15 April 2011, 19:06 Friday

Thanks again Chris for pushing us towards the light. I feel very good that we made a sound decision going with an AT screen. I'm still kind of stunned that my wife went for it. There was no "maybe" about it when I asked about getting a new screen before!

It's a 2.40:1 Seymour AV Center Stage XD in the retractable, motorized, tensioned 141" version, and we only had to drive half an hour to pick it up! It might be a little on the big side for our 9-10.5 foot viewing distance, but we've always enjoyed our screens on the big side.

While we considered selling the 120" Da-Lite Hi-Power screen, we've decided that for the $300 we could probably get for it we'll just hang it in the garage and lug it out to the backyard for the occasional "drive-in" experience.

Thanks again MadMac and Chris!

Speaker placement with a 120" screen

Speaker placement with a 120" screen

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