Axiom Home Page Forums General Discussion Home Theater Large great room. 7.1 speaker placement & dipole v

Dean Big thanks! I wrote that down. :o) My wife told me to just Google an HTML cheat sheet. Seems all those use < > around commands. Is the [ ] a special command type that creates the box around the text being quoted? I will need to learn some basic HTML... Like... "Help, please tell me where the baños is!"

It's not HTML. It's UBBCode. You can find more information in this board's FAQ.

This code used above is actually UBB Code which is a variation of HTML Code. Since you’ve used some of them already you have noticed that above the text window on the “Reply” screen many of the codes are selectable with icons. Even the Quotes are there. So you can just type or cut and paste your text into the window then highlight the text you want to quote and hit the “quote” icon.

P.S. Darn, he beat me again.

Maybe, but I think your response was more helpful.

I never would have considered this. I love the brainstorming. I do not think I want to move it, but then that is not cast in stone


How far is far enough? Front of speaker 3' out so it is out equally as far as the end of the bookcase? More? In this case, how far would I need to move the lft frt spkr out to not be affected by the bookcase?

From your an Zimm's comments, I am confused. (nothing new there ;o) What directions are you speaking of sound waves coming from say the front left spkr?
1) from front of spkr 180º? (more or less than 180º?)
2) sound waves emenating from the side of the speaker towards bookcase (or wall on other side)?
3) from back of speaker to front wall behind speaker, then bounce in all directions including towards bookshelf (or wall side)?

Is it #3? If so do I get a prize?



[is L/H 'left hand'?]




Dean, now we're getting a bit too far outside the box.

Cheers,
Dean [/quote][u][/u]

Well an M2 on top was nixed by the boss (and I agree) for how it looks. the only option I'd have for M2's is 1 or 2 under screen, upside down, tilted up. I guess which is better w/M80's, two M2's vs. a VP150 would be an Alan question. I'd guess he'd come down on the VP150 side, since they designed them for that application.



Dean, what did you have as a center before the M80? Can you describe how it did not do the job well enough?

When I saw you d THREE M80's, I was afraid to ask where #3 was! Considering the M80's overpowering a center, I'd guess the twin M2's (4 ohm) with 91dB would be more overpowered
than the 6 ohm VP150 w/ 95dB sensitivity.


Sir, the thought never occurred to me.

If I did use QS8's for backs and mounted them on the ceiling, I'd be looking for location/distance that kept them far enough forward as to not blast people (my wife ;o) that may hang out in the kitchen or dining room so much. But also, try place them far enough behind the imaginary line crossing the room through the primary listening position as would give the best sound.

If you were to draw a line from one side of the room to the other between the side speakers, you would pass through the primar list. pos. (just off center to rt.). These distances are taken from that line.
I) Due to a skylight (kitch. side), the closest behind the primary listening position line would be 4'. I'd guess this would be closer than optimum.
II) 5', 6' or 7' behind listening position would work too.
III) the distance between the backs could be about 13' - 15'.
IV) Would it be better to have the backs be the same distance from: a) the wall on the SBR side and the kitchen cabinets on the SBL side? OR b) equal distance spacing on each side of the sound field, leaving the SBL a lot closer to the cabinets say 24", while the SBL was say 52" from the rt. wall?

3 to 4 feet is perfect. The main thing was to eliminate the first reflection from your L/H main hitting the bookshelf or near wall. It should sound better if the first reflection travels to the far wall just like on the other side. As long as the front of the speaker is even with the bookshelf that should be fine. That only other issue would then be the speaker getting in the way of the bookshelf if depending on how far out you move the mains from the TV.

Actually you win the prize because it’s all 3.

First let me digress. Ideally you want your speakers symmetrical with your room and listening position. In the real world that’s not likely to happen unless it’s a purpose built HT/Music room. So the goal here is to come up with a balance between the most symmetrical setup and the one that’s most ascetically pleasing. Luckily symmetrical is also often ascetically pleasing.

To maintain symmetry between your listening position and the room I would leave the TV and seating just the way it is. Also the surround side location you plan is perfect. If you go 6.1, the rear speaker should sit along the center line of the room forming a triangle with the surround sides. If you go 7.1 the surround backs should be located on either side of the peak of the room to form an arc with your surround side speakers. How far apart and how far back should depend on where they blend the best with the surround side speakers. Obviously your center speaker is centered on and above or below your TV. Which leaves the Mains.

That bookshelf and wall break up what is otherwise a very symmetrical area. Since speakers radiate sound in all directions you can’t eliminate reflections from it completely so if it causes problems with your front soundstage (and it may not cause anything you notice) the goal would be to minimize the reflections off it while trying to maintain reflections that are symmetrical with the other, R/H, wall. As long as the front of the speaker is even with the bookshelf you will solve most of this. Another issue is the reflections off the front wall behind the speakers.

I’ve read that it’s best to have the front of the speakers about 3.5 feet from any vertical surface to prevent the reflected sounds from interfering with the timing cues your ears are receiving directly from the speakers. Mixed timing cues can blur the imaging of what you’re hearing. Some people who find this annoying but can’t move there speakers will use diffusers on the reflection points to break up the sound so it’s not reflected directly at the listener. Actually having the bookshelf there is better than having a bare wall since the odd shapes and soft texture of the books will act like a diffuser.

The main reason I suggested moving your front speakers out further is that I couldn’t tell from the picture that they are probably already far enough out. The reason I suggested moving the bookshelf is I was afraid it might end up that the best sounding speaker position is so close to it that it blocks access to the bookshelf. The reason I suggested moving your main speakers farther to the side of the TV was to try and widen the front soundstage to cover more of your seating area rather than be narrowly focused around the TV. Also sound reflects off the TV screen which can cause the problems discussed above as well as colour the sound. This often happen to center speakers who’s fronts are even with the TV screen and is usually remedied by moving them out in front a little bit. As for your main speakers a good starting place might be to move them away from the TV symmetrically on either side of it so that the L/H speaker is about half way between the TV and the bookshelf.


Yes your left hand as facing the TV.



I thought that nothing was of limits when brainstorming. now where’d I put that sledge hammer.


Cheers,
Dean

So what tipping point of price and power makes one consider going separates?
1) If you want or think you may want at some point in the future, more than say 130 wpc (like Denon 3808 AVR)? A higher wpc power #?
Being a newbie to all this stuff, I cannot even conceive of a need for more that 130 wpc.

I'd don't have closet to convert to an AV stack closet. I can't imagine how many bucks you could soak into even a modest separates set up. Like I said, I'm green. ;o)

I had a VP150 at first, still do and even used it as a 6.1 rear speaker for awhile. Because the VP150 and M80s are different designs they are going to be sonically different even though they are “timber matched” designed to sound as similar as possible. Even the M22s I suggested sound a little different than the M80s. In a perfect world it’s recommended to use identical speakers across the front but even identical speakers in different locations will have some sonic differences. Add to that I sat very close to the speakers about 6 feet which does nothing to help the speakers blend together and I just found it annoying. Apparently I’m more sensitive to sonic differences than many people, just easily annoyed, or both. However, the only reason the difference became annoying is that I experimented with using the mains to emulate a center speaker (phantom center) just the same way normal stereo works. This sounded noticeably richer and blended more smoothly across the whole front soundstage.

I did experiment and found that the farther back I sat the better the VP150 blended with the M80s. I also have a temporary setup in another room pending a move and have found that the VP150 blends nearly perfectly with the M22 mains I have in there even though they are even closer that in the other room, and the M22s sound very similar to the M80s. The difference here is that the VP150 and M22s are all out in front of the TV some so reflection off the screen aren’t colouring the sound as much.

At the end of the day I’m just being a perfectionist because I can. The VP150 is IMO as good a dedicated center speaker at blending with the mains it’s designed for as any other I’ve heard. And the vast majority of people would notice any difference especial the farther one sits from the speakers as that allows them to blend together better.



Assuming your picture is fairly to scale I would start by trying the single QS8 at the blue dot and the dual QS8s at the red dots. Here symmetry around the listening position is probably most important. And don’t worry about reflection with the QS8s as they are designed to take advantage of them to enhance the surround effects.





The QS8s are actually very easy speakers to place I only suggest that you experiment with their positioning because it sounds like you want to get the most out of your system and that’s the best way to do it.


Cheers,
Dean