# Sound Decision - please help



## jmtenthusiast (Jan 23, 2016)

Do I place my LR speakers at the extreme ends of the projector screen (120 inch)? I suppose that will be good for effects, left to right and vise versa? If I do that, they will be aprox., one foot away from the corner wall. I have read that it is important to keep the LR away from the corners, at least two feet, maybe three? So what should I do? Leave them at the corners or bring them in?

Thanks


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## NBPk402 (Feb 21, 2012)

Mine are angled toward the MLP with the rears almost touching the side walls. One difference is I have 3'x3'x3' horns so the rears are only about 10" wide...this allows me to go this wide and still have them aimed at the MLP. If they are aimed at the MLP they should be fine (I would still make or buy first reflection panels though). In my setup which is with a 15' wide screen there isn't much room for me to move them away from the walls, but it sounds great the way we did it. If your speakers are narrow enough you could try moving them around... I would try it first with the speakers evenly spaced from the side walls and each other, and then aim them toward the MLP. Then i would try them farther apart and see what you like best.


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## theJman (Mar 3, 2012)

jmtenthusiast said:


> Do I place my LR speakers at the extreme ends of the projector screen (120 inch)? I suppose that will be good for effects, left to right and vise versa?


Unless your screen is acoustically transparent there really isn't another viable option. Be sure to angle them towards the MLP though.




jmtenthusiast said:


> I have read that it is important to keep the LR away from the corners, at least two feet, maybe three? So what should I do? Leave them at the corners or bring them in?


Should speakers be away from side walls? Yes. How far? That depends upon several factors, so there's really no set answer.

What are the walls constructed from, sheetrock, plaster, something else perhaps? Are there any acoustic treatments or things like heavy drapes in close proximity? Does the tweeter have a waveguide? More comes into play then just that, but the bottom line is it varies with circumstances. One foot may not prove to be ideal, but it could certainly be worse.


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## witchdoctor (Feb 21, 2016)

jmtenthusiast said:


> Do I place my LR speakers at the extreme ends of the projector screen (120 inch)? I suppose that will be good for effects, left to right and vise versa? If I do that, they will be aprox., one foot away from the corner wall. I have read that it is important to keep the LR away from the corners, at least two feet, maybe three? So what should I do? Leave them at the corners or bring them in?
> 
> Thanks


The rule of thumb according to Dolby is that they are at angles of roughly 30 degrees to the main listening position. I printed out a paper protractor, placed it at my main listening position and ran a string to my speakers to help get the angle. I also used a tape measure to try and and get them both the same distance from the listening position. 

http://www.dolby.com/us/en/guide/surround-sound-speaker-setup/5-1-setup.html

Hope that helps and yes, being at least two feet away from the wall is ideal.


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## jmtenthusiast (Jan 23, 2016)

Here are some pictures to help clarify.

The speakers will be behind the screen. The screen will be a Silver Ticket AT, 120", it should arrive tomorrow via UPS. Although the speakers are shown, right side up, in reality I mount them upside down. I am doing that to keep the tweeters as much in line with the seating position as possible. The towers will be angled down towards the MLP. I have drapes that will line both sides, all the way, front to back. They are thick velvety blackout drapes.

1. Are you recommending diffraction on the front left wall, or absorption?

2. Should I build a wall on the right front, that would define the space, maybe 2 1/2 out, ceiling to floor?

3. What would you do with the garage door? I have extra mineral wool, I can fill the garage door with it. Or, should I make a diffraction wall out of the garage door? I don't know what I would use to make a diffraction wall, it would have to be a very light material, the door needs to go up and down.

4. Any additional thoughts?

5. btw - there's a shot of the tweeter. 

Thanks for you help! I'd like to get this sorted out before the screen arrives.


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## theJman (Mar 3, 2012)

Given that you're installing an AT screen you have flexibility with regards to the placement of your mains, but from the pictures it seems you've already decided on their location. One observation... your center appears to be a bit small for the volume of space so you might find it struggles to provide sufficient output. Only time will tell though, so perhaps that won't be the case.

1. I tend to favor absorption over diffraction, but that's more a personal preference than anything else I suppose. While absorption can 'deaden' the sound I prefer to eliminate (or at least diminish) objectionable sounds.

2. I'm not certain I understand what you're asking. Are you referring to a wall on either side of the screen to accommodate the L/R speakers?

3. This may seem like a dumb question, but is this space going to be a workshop, garage _and_ HT. Not sure if the pictures represent it accurately at this point, given you're still doing construction, but visually it seems to extend the term "multi-use space" to a level heretofore unknown. :smile:

4. Yes, have you decided on the first movie you're going to watch? :wink2:

5. The tweeter has a waveguide of sorts, so placement within close proximity of a wall shouldn't be as much of an issue as it would be for most other speakers.


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## jmtenthusiast (Jan 23, 2016)

#2 To clarify, the front wall on the left hand side, (corner) will have some sort of acoustical panel. On the front wall, right hand side (to make a corner), maybe I would have to build a wall to make it symmetrical and then put an acoustical panel on it also.

#3 I plan on a 4 x 8 ft, H.O. slot car track recessed into the ceiling. It will lower automatically with a spare garage door opener motor. On the left hand side behind the curtains will be an entire wall of movie memorabilia. Hans, frozen in Carbonite... Indiana Jones skeletons pierced with those spikes coming out of the wall... Some kind of Star Trek thing too... Before entering the theater side, you will be treated to Laser Discs on the walls. And then of course, I have ramps for my jeep, and Drive-In Theater Speakers to hang on the car window. Nothing like going to the Drive-In! You can see the speaker pole and speakers in the near the corner in the back of the room. Projects and dust will be arranged outside!

#4 I love your sense of humor! Probably Avatar since my wife never got a chance to see it in the theater. It should be fun.

#5 Additionally I would like to make the ceiling appear as if the stars were out at night.

#6 When the neices and nephews come over, I'll send them to the Drive-In theater. I'll put the windshield down and let the kids "have at it." The only thing I'll warn them not to do is, "When I'm gone, don't open that curtain!"


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## theJman (Mar 3, 2012)

It sounds like you're creating a fun and irreverent space, one where good memories will be made. In the end that's what it's all about, yet sadly too many forget about that part in their seemingly endless quest for perfection (which is an unachievable goal). I hope the funhouse gives you and yours a lot to talk about for years to come!

BTW... Avatar is an excellent choice. On a properly tuned and configured setup that movie is an audio and video treat for the sense. I've used it numerous times in my reviews for that very reason.


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