# Need Sound Design Advice



## Sthrndream (Apr 21, 2006)

I posted this in the other forum where nothing fits. Sorry.

Hey guys. I need some advice. I have a 7.1 system. Here’s the equipment

Speakers: Mains: Polk LSI 25s
Center: Polk LSI C
Surrounds: Polk LSI FXs
Surround Backs: Polk LSI 7s
Subwoofer: SVS PB 12 +

Preamp: Sunfire Theater Grand IV

Amp: Sunfire Cinema Grand 7

Other Equipment: Sony DVP CX 777es
Behringer DSP1124 Parametric EQ
Monster Power 3600 MK II 
Sony KSPW51 RP TV

Fantastic system IMHO. Sounds great. But here’s my situation. I want to maximize the sound.

Look at the picture, here is my room layout. It’s in a living room on the east side with an open air kitchen to the west. Gas fireplace is on the south side with five foot windows on either side as well as a window over the fireplace. In the middle north side of the picture, there is an open hallway to the front door. Carpet and wooden blinds dress the area. As you can see, acoustical properties are not optimized for my open room.

My subwoofer is in the SE corner below my right surround speaker. My surround backs are over the fireplace on the mantle. Unfortunately my entertainment center (10 feet) takes up the entire north wall with 24” on either side.

What I need to know from someone in the know is this. 

1. Am I better off moving the entertainment center against the East wall, surround backs mounted on penta (sp) mounts from the ceiling in the kitchen and sub against the north or south wall?
2. Or is this current setup the best? One might say the only way to find out is to move it and determine for yourself. I am hoping someone with acoustical knowledge can comment.

Looking forward to hearing from you!


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## bpape (Sep 14, 2006)

*Re: Need Advice*

Personally, I'd turn it. Symmetry left to right is important for good imaging and surround effects. Right now, you don't have that.

Also, when it's turned, you'll have some space behind the prime seating which will yield smoother bass response instead of sitting right against a wall where you get all the modal problems buiding up.

Bryan


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## Sthrndream (Apr 21, 2006)

*Re: Need Advice*

Bryan, 

Thanks for the reply. I had a buddy also do a room calculation for frequencies. Here are the uploaded images. They start at the walkway and cut at a 45 degree angle from NW to SE. Based on his analysis, would you concur. He is an ameteur, not a pro, so thats why Im asking. And, if that is the case, do I still turn?:hail:


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## Wayne A. Pflughaupt (Apr 13, 2006)

*Re: Need some good advice*

I think I’d go with the east wall arrangement. As it is now, for instance, you have your right speaker in a corner, and the left one isn’t. The left speaker is going to have reduced bass output compared to the right, which may lead to things sounding unbalanced.

Another benefit, I feel, is the uniformity of the area that the front speakers will be firing towards. That tends to help dispersion, from what I’ve seen in similar set-ups in places I’ve lived.

As a side benefit, you might be able to see the TV from the kitchen - always nice when you want to run in to refill your drink during a movie. 

Regards,
Wayne


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## Alan Brown (Jun 7, 2006)

*Re: Need Advice*

Sthrndream,

I concur fully with Brian. The current setup has so many serious compromises, there's no way you have heard how good your equipment or your software can actually sound. I'm also surprised you could tolerate all the reflected light from the three windows opposite the TV. I've never found any wood blinds that block light near well enough. Turning your setup would also allow for viewing of the TV and better sound from the bar area seating during parties, etc. 

Your buddy's room calculations only work for predicting closed rectangular spaces. With all that open area on the West, there is no practical way to predict all the resonant modes.

Your side surrounds should be located opposite your primary seating location, or a little behind. The center back channel speakers should be behind the primary listening spot and away from the corners, if possible. Corners are usually the worst locations for any speaker.

Best regards,
Alan Brown, President
CinemaQuest, Inc.
ISF, THX, SMPTE, CEDIA

"Advancing the art and science of electronic imaging"


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## Sthrndream (Apr 21, 2006)

*Re: Need Advice*

Thanks for the reply. I want to say I agree with you too, hence seeking the advice. The only immediate compromise I would give up at this point is the subwoofer. We (my wife and I) primarily sit in the east corner next to the sub. I enjoy (cant speak for her) FEELING THE BASS.

I dont know id still be able to do that. And thats hard to give up....lol


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## Alan Brown (Jun 7, 2006)

*Re: Need Advice*

If your floor is wood framed, and the sub is spiked to anchor it through the carpet, much of the tactile whallup that occurs with film soundtracks will travel well in the room. I have 15" woofers in the two Altec Lansing Model 19s in my theater at home. They are quite large and are on casters to enable cleaning under and behind them. I get plenty of impact and substance even sitting two thirds of the room away from the speakers. They are inordinately efficient (100.5 dB) and my floor is wood framed.

Elephants use infra-sonic signals to communicate over as much as 15 miles to other herds when they find water or are looking for mates. Low frequencies don't have to originate from right next to you to be effective. It's usually best to move subs out from room boundaries, away from pressure zones, for more even distribution of energy in the room. This helps deliver balanced frequency response to other seating locations in the theater. Peaks and nulls are more moderated without the use of equalization.

In an odd shaped room like yours, experimentation with subwoofer location is usually the only way to optimize its performance for balanced performance. It may even work best in a corner but until you try different options you won't know for sure.


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## MrPorterhouse (Jul 29, 2006)

*Re: Need some good advice*



Wayne A. Pflughaupt said:


> [font=comic sans ms,verdana,arial]I think I’d go with the east wall arrangement.



Absolutely. I agree with the East Wall arrangement. Sonically, its your best option by far.


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## Sonnie (Apr 11, 2006)

*Re: Need Advice*

Actually this should be in Home Theater Design (I think)... so I'm gonna move it there and also merge your replies to the other thread into this one thread.


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## bpape (Sep 14, 2006)

Alan is correct in that the calculations are for optimal, closed, rectangular spaces. In your situation, there are a lot of other issues to concern yourself with.

As for the sub, you're moving toward more accuracy. Sitting right next to a sub sitting in a corner is anything but accurate - sorry. If you want to feel the sub get it set in the appropriate place and get a sub capable of making you feel it. Don't compromise the whole spectral balance by sitting basically in a corner - the worst place possible to sit in a room and generally the worst place to put the sub too.

Bryan


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## Sthrndream (Apr 21, 2006)

ok you guys sold me. Looking for some type of mount here locally for my lsi 7s.


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