AVS Forum banner
Status
Not open for further replies.
1 - 15 of 15 Posts

·
Registered
Joined
·
45 Posts
Discussion Starter · #1 ·
I have a room that is 12'10"L x 11'W x 8'H. I'm looking for help on speaker placement for a 7.1 system in this room. Fronts are BP3000Tls, center CLR3000, and sides BPVX/Ps by Definitive Technology. The only speakers that aren't bipolar are my rear surrounds, which are a pair of JBL L5s. My seating is about 3' from the back wall and center of room. I would like to know how high and forward or back on the side walls the surrounds should be? I could actually use exact placement for all of these speakers in this room. I was told several different things from installers and am very lost. One guy told me to mount them about 4' forward on the side walls and 6' from the floor to the tweeter in the null position. I was also told the height of the tweeter on the surrounds should be at the same height my mains and other speakers are at. Another guy told me the height didn't matter as long as I was in the null position and that it was more important to keep them out of heads way. And another guy told me to put them forward of the null 3' above ear level. Now, I thought you where to never put these speakers ahead of the listening position. As you can probably tell I'm very confused and would great appreciate any advice.


Thanks in advance,

Michael
 

·
Registered
Joined
·
3,947 Posts
Mike, all of the generalizations are adequate for starters. If you can, move your seating ahead a couple of feet, and the sides directly to the sides, maybe 1 to 1-1/2 feet down from the ceiling, and the rears at the same height. This will allow your rears more room to propogate (spread), and give you less localization.


A greater concern is that you keep the front towers away from the side walls, as well as away from the rear wall (front of the room), and toed in a little. Mine are about 18" out from the wall, and about 2' from the side walls, and toed so each points at it's end of the sofa. To me, cross-firing hurts separation, plus I have seating to the sides of the sofa.
 

·
Registered
Joined
·
45 Posts
Discussion Starter · #3 ·
Larry, thanks for the great advice. If I understand you correctly in regards to my seating. I should move it forward putting it 4' from the back wall and 3' from the front of my rear surrounds? And my side surrounds should be directly to the sides of my seating (center of seating) at 5'1/2" with the top of the side surround 1 to 1'1/2" from the ceiling? As for my fronts, should I have them firing at each other or toward the side walls with regards to the side firing subs built into them? I can do the 2' from the side walls and toe them at the ends of my seating which is a 6'6" sofa centered in the 11'W room. Now if I place them 18" from the back of the front wall that puts the front edge of my sofa 3' 9-1/2" from the speakers. I guess my question becomes should I sacrifice inches or feet from my seating to the fronts or from my seating to my rear surrounds? I have 36" Sony Wega HDTV between the front speakers that my center will sit on 4 to 5" above the tweeters in the fronts. I also have an M&K sub I was planning to put next to one of my fronts. Also, I have a rack next to my other front speaker. Should I move any of these? I have dedicated 20AMP circuits for my sub and fronts so i couldn't move the sub far. Not sure if i could move my rack too far either since all my speaker cables are custom lengths. The cables feeding the fronts are only 10feet cables. Does it matter if the tweeters in the surrounds are at different heights than the fronts and center? Would I be correct in assuming that the tweeters in the side and rear surrounds need to be at the same height and the tweeters in the center and front speakers should be at the same height?


P.S. I loved your theater pics. I noticed your a master electrician, I'm an electrical engineer. I noticed you put in a sub-panel for your theater. I should have did that, but instead I ran two 20AMP circuit to my rack, one 20AMP to my sub and center, one 20AMP circuit to each front, and 1 20 AMP to another sub and my surrounds. It never dawned on me it might have been easier to put in a sub panel. I'll probably do that when I build a bigger theater in the basement.


Thanks again for your advice.


Mike
 

·
Registered
Joined
·
3,947 Posts
Mike, to answer your first hundred or so questions, yes, you have the idea; I didn't realize that my suggestion would place you so close to the fronts. However, it sounds like the results would place your ears midway between the front and rear speaker faces, or just a hair back. This actually sounds okay. Experiment with the sides off if it helps isolate the subtleties.


I have my subs facing each other, which I believes aids in bass via 'compression' of the space between them. As for the second sub (third, actually), I'd love to suggest you place it behind your sofa. You have surround-speaker receptacles; believe me, the surrounds don't need the entire circuit to themselves. Even if it takes use of a temporary extension cord, try it. You have enough bass from the front. Be sure to set the phase adjustment carefully, in any location.


Your tweeter-height assumptions sound okay, but to me, they're not that critical, especially in the surrounds; what matters is that heads don't block other listeners' ears. My center happens to be below my picture, but it still sounds like the audio comes from the screen; I'd like to move the image down and place the center above as an experiment, when I find a suitable bracket.


You have plenty of electrical capacity; don't sweat not having a sub-panel. I only did it for convenience of running the wires, and to have local control; it's not a necessity. Your rack should probably be a couple of feet from the speakers. What is your amplification, by the way?
 

·
Registered
Joined
·
45 Posts
Discussion Starter · #5 ·
Larry, thanks again. Thanks for being so helpful and answering my hundred or so questions :) It must be that engineering mentality :) I'm a little worried I'll be too close to my fronts, but I want to get the side surrounds right since I want to mount them and add outlets below them. I don't plan to just have the surrounds on that one circuit, but rather pull from an existing circuit to them. My whole reason for adding the surround outlets is because of a doorway at the back right side of the room. The only things that have there own circuit are each main BP3000TL. As for amplification, I'm running two amps. The side surrounds and center are powered by a B&K Reference 3220 and the high/mids on the mains are powered by a Proceed HPA2 amp. The back surrounds are powered by the my Denon AVR5803 receiver. As for being close to my fronts, I'm not too sure about being that close. My TV will sit I think 18 or so inches back from the front of the mains, which I hope isn't too close for a viewing distance. The other thing I worry about is the stand for my tv is a wide one with 8 or 9 inches to the sides of my tv. What would be optimal for distance from the fronts? Should I change the distance for the surrounds and seating to add a little more up front and about how much? Is it okay to having seating end up middle of the room or is it better to be more back, which ends up sacrificing the surround field? A double edged sword it seems. As for my sub i hate to move it where I can't see it. Are you saying to put it on the back wall centered behind my sofa or right behind my sofa? I also have room in the corners of the room for it as well. I have my 3rd sub in one of those back corners already. As for the tweeters on my surrounds are you saying the important thing is to have the tweeter at least above ear level to avoid blocking it with someones head? As for the sub-panel, ya I know I'm good on powered to the room, but man i wish i would have thought of putting in a sub-panel before i pulled all those cables. It's like you said it would have been nice for convenience of running the wires, and to have local control.


Thanks again you have been a great help. I wish I would have signed up at the forum sooner.
 

·
Registered
Joined
·
841 Posts
Shishio,


I am using a 7 speaker Definitive Technology setup in a room slightly larger than yours.

I am currently using 4 BPVX surrounds. I used 4 BPVX/P models for about 8 months but found highpassed BPVX's worked better for me.


In a room your size I would suggest mounting your side surrounds directly across from the listening position with tweeters up about 5 1/2' feet from the floor.

Definitive Tech actually recommends mounting their bipolar side surrounds abount 2' behind the listener. A null is produced from a dipolar speaker.

Mount your rear surround tweeters at the same height as the sides.


Also as Larry points out. If possible keep your Mains out from the front and side walls.


John
 

·
Registered
Joined
·
45 Posts
Discussion Starter · #7 ·
Thanks guys for responding to my post.


Where should I place my listening position. I have my tv screen 3' 2" from the front wall. I have about 1' 2" I could move the tv back. I'm thinking, based off advice from you guys on the forum, I'll put it about 1' back from the center point between my fronts and rear surrounds. I think this would put my listening position at 5' 1/2". I think that puts me 4' from the screen. I think i might have to move seating back another foot, but then again if it sounds better I'll live with being closer to the screen. Do you guys think I'll be too close to my 36" tv screen?


Mike
 

·
Registered
Joined
·
45 Posts
Discussion Starter · #8 ·
I moved my fronts out 18" from the front wall and 1' 6" from the side wall on the left. I can maybe get a few inches on the right main from the equipment rack, but not much. This put me about flush with my 36" tv screen. My tv stand is a wide one,as I mentioned, which puts 8-to9" of space between my tv and front speakers. Should I move the speakers as close as I can to my stand, which would put the mains 5' apart or leave them at 6' apart. The latter leaves 6" of space between my tv stand and the front speakers. Like I mentioned, I could move the tv back 1' 2" leaving it recessed from the front speakers by that distance to place the viewer at little more away from the tv screen. Currently, the distance between my front speakers and my rear surrounds ends up being 8' 8". So what would be the optimal placement for the listening position (3',4',5' from the rear surrounds)? I'm not sure bur I imagine it is not a god idea to have seating end up in the middle or closer. I want to give my surrounds as much space as I can without ending up too close to the front speakers and tv screen. Should I move the fronts back more towards the front wall? Also, I was going to place my M&K MX-5000THX MKII sub in the front of the room next to my left main, but I'm not sure now if this best. Is this a good idea and what kind of space should have it from the front speaker? I could also place the sub in one of the rear corners of the room if this is better.


Somebody please help me?


Michael
 

·
Registered
Joined
·
3,947 Posts
The distances you are asking about are small enough that you can tell more by experimenting than we can tell you.
 

·
Registered
Joined
·
45 Posts
Discussion Starter · #11 ·
I was hoping to get the surrounds mounted, since everything is disconnected right now. How are my current assumptions. With my rear surrounds 8'8" from the fronts, where in that distance would be ideal for the seating? Is it better to be in the center of that distance or farther back or forward? This will affect where my side surrounds end up. And how about some tips on my M&K sub?


Thanks again everyone.
 

·
Registered
Joined
·
3,947 Posts
Shish, that's what I was addressing: there's no one answer to "Is it better to be in the center of that distance or farther back or forward?" You have to try it, but I'd choose right in the middle (with all delays zeroed), and then try a foot or so in each direction.


The sides could be left out, or find a way to place them temporarily. (Got any thirsty friends and some beer?) If it were me, I wouldn't let needing to patching a couple of screw holes stop me from moving them around after a week or so in each position.


As for the sub, if I had a separate one, I'd place it directly behind the sofa (if not in the way) for close physical coupling to the seating, for that "seat-of-the-pants") feeling. However, try a corner, too. Subs require more trial-and-error than any other speakers.


P.S., be a little more patient; many of us can't get here more than once per day.
 

·
Registered
Joined
·
45 Posts
Discussion Starter · #13 ·
I thought maybe it was a bad idea to be in the center for your listening position, but I'll try it the three ways and see. As for the side surrounds, I guess I could mount them temporarily. I was hoping to avoid moving them several times, since I want to put outlets centered directly under each. I don't want the draping power cord because my walkway is so narrow. I want the power cords up and out of the way so nobody can accidentally kick or trip over them. This leads me to another question I just posted a couple days ago. How do I run power to these speakers? The speaker wire has to come up the wall to the speaker and travel along or near the outlet. So how do I prevent noise or 60Hz hum from entering my speakers? I know it is a big 'no-no' to run power and other cables next to or in parallel. It's hard to avoid this since both the power and speaker cable are going to the same spot almost. I could run power down to the speaker from the unfinished attic, but they still will meet up at the speaker. I suppose I could come down the wall a stud or two over. Is there any good way to insulate the power line from the speaker wire or is distance the the only good way? I'm thinking 18" to 24" should be plenty.


P.S. Sorry if I seemed impatient, I guess I'm eager to get my system up and running. It really sucks watching even TV with just the TV speakers for sound.
 

·
Registered
Joined
·
3,947 Posts
For temporary use, you don't need to worry about the cords. However, when you're ready to finalize the mounting, speaker lines are of a high-enough current that 60Hz noise won't be audibly generated, and the speakers themselves are not sensitive enough to produce any induced signal.
 

·
Registered
Joined
·
45 Posts
Discussion Starter · #15 ·
Thanks again Larry. How does 60Hz hum become audible then? I've read several posts about 60Hz hum and how important it is to properly route cables. Was it all bs? And what about cross-talk? Cross-talk is certainly going to occur with two or more conductors ran in parallel to one another. In any case, I hope your right, since I plan to wire my surrounds today. Any tips on the electrical? I plan to run it in the unfinished attic between some 2 x 2s to avoid drilling through all the joists. If I ran conduit up there, would it be alright to lay it across the joists or do I need to protect that too?


Thanks again Larry you have been so vary helpful.
 
1 - 15 of 15 Posts
Status
Not open for further replies.
Top