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Discussion Starter · #1 ·
I have a 7.1 speaker system. My question is, for the rear or back surrounds, I have two options; both are 7 feet above the listening position. One placement is only 2-3 feet behind the listening position, the other is about 8-9 feet back. Which would sound better for 70% HT or movies and 30% music? I am about 12 feet from main fronts. The side surrounds are direct radiating and at direct sides of listening position. Any suggestions?
 

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Quote:
Originally Posted by psychdoctor /forum/post/0


I have a 7.1 speaker system. My question is, for the rear or back surrounds, I have two options; both are 7 feet above the listening position. One placement is only 2-3 feet behind the listening position, the other is about 8-9 feet back. Which would sound better for 70% HT or movies and 30% music? I am about 12 feet from main fronts. The side surrounds are direct radiating and at direct sides of listening position. Any suggestions?

I would go with second option (8-9' behind) and spread surround back speakers about 9.5-10.5' apart.
 

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axs


You need an array of surrounds going around the room direct radiating types are better, look for a model that will exhibit a nice low end response for the size of the room and place at least four for each sidewall and four to six for the back wall.


It's doable. That is surrounding you with the least minimal holes in the surround!



To give you an idea what I did here you go it's easy if you know what to do and pictures say more than a few words, its still in the design process and want be completed to around summertime 2007, it started back in the summertime of 2006.








It's got multiple uses this array has an overhead surround, when finished it would be made up of no more than x8 JBL control 1.



So think it though a few more times mate and get checking on the installation.
 

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Quote:
Originally Posted by JBLsound4645 /forum/post/0

axs


You need an array of surrounds going around the room direct radiating types are better, look for a model that will exhibit a nice low end response for the size of the room and place at least four for each sidewall and four to six for the back wall.


It's doable. That is surrounding you with the least minimal holes in the surround!

Thanks for your suggestion, but I am not the one looking for speakers or placement advice at the moment. I was just making a suggestion to the OP.
 

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Well it would depend on how good a surround effect he wants, the Dolby diagram above is a bit misleading, why does everyone think 7.1 must be a single matching speaker for the three-screen and one of each for each sidewall and two for the back, hence 7.


Good god man you'll have gaps in the sound in those positions, and I've already been there and it sucks big time, my way is more exact surrounding.
 

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Quote:
Originally Posted by JBLsound4645 /forum/post/0


Well it would depend on how good a surround effect he wants, the Dolby diagram above is a bit misleading, why does everyone think 7.1 must be a single matching speaker for the three-screen and one of each for each sidewall and two for the back, hence 7.


Good god man you'll have gaps in the sound in those positions, and I've already been there and it sucks big time, my way is more exact surrounding.

Wow !!! You sure seem to be enjoying your more than a dozen speakers (I couldn't get an exact count though), but 7.1 is plenty for me.


I think I saw these pictures somewhere on one of these forums before too.
 

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axs


It's not just about 5.1 6.1 or 7.1 it's more about covering the sides rear and overhead to create a ((sound bubble)) as well frequency response sound pressure level and being able to think, to create something that will place your best mates in the dust.


When completed there should be around x22 I was going to go for a staggering x32, but as it all started to come together a piece at a time I discovered around x22 would be the ticket for home cinema surround.


Go on, let me hear you say it
 

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Discussion Starter · #9 ·

Quote:
Originally Posted by JBLsound4645 /forum/post/0

axs


You need an array of surrounds going around the room direct radiating types are better, look for a model that will exhibit a nice low end response for the size of the room and place at least four for each sidewall and four to six for the back wall.


It's doable. That is surrounding you with the least minimal holes in the surround!



To give you an idea what I did here you go it's easy if you know what to do and pictures say more than a few words, its still in the design process and want be completed to around summertime 2007, it started back in the summertime of 2006.








It's got multiple uses this array has an overhead surround, when finished it would be made up of no more than x8 JBL control 1.



So think it though a few more times mate and get checking on the installation.

Whoa! That is insane! Your whole room is speakers!
 

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Discussion Starter · #10 ·

Quote:
Originally Posted by JBLsound4645 /forum/post/0

axs


It's not just about 5.1 6.1 or 7.1 it's more about covering the sides rear and overhead to create a ((sound bubble)) as well frequency response sound pressure level and being able to think, to create something that will place your best mates in the dust.


When completed there should be around x22 I was going to go for a staggering x32, but as it all started to come together a piece at a time I discovered around x22 would be the ticket for home cinema surround.


Go on, let me hear you say it

I don't understand how you can drive that many speakers. DO you use splinters? or Several Y cables?
 

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Discussion Starter · #11 ·

Quote:
Originally Posted by axs /forum/post/0


I would go with second option (8-9' behind) and spread surround back speakers about 9.5-10.5' apart.

Your suggestion is what I am using now and they are about 7 feet apart. I was watching WOTW and when the lightening scene came on, it seemed to shoot over my head! However, the speakers are relatively inconspicuous in terms of sound. I mean, hard to notice is a better phrase. I guess that is the way the backs are suppose to be? WHen I up the level to about +2db (78 db with SPL) I noticed that my surround sides sort of blended with the backs and were less pronounced. But when I lowered the backs to level (75 db with spl), the sides were much more pronounced but the backs were quiet or at least I could not tell they were on.
 

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Quote:
Originally Posted by psychdoctor /forum/post/0


I don't understand how you can drive that many speakers. DO you use splinters? or Several Y cables?
psychdoctor


It's ran just like any normal commercial cinema that I have worked at in the past, only this time I'm taking it to a newer level of playback in the home.



Well, if you what a piece of the action just look around you're room and judge how many you'll need.



I have played the same scene from War of the Worlds many times over, even with the three-screen and LFE.1 turned off, where only the sub bass extension is used along with the split-surround array.


I haven't ran War of the Worlds with the newer JBL control 1 that are placed overhead where it gets it's signal from the matrix back surround output, similar to how the Dolby SA-10 performs. But I doubt it very highly no one has tried to explore the usage of the split-surrounds on this film which do work very well to heighten the dramatic moments when everything and everyone around is vaporized!


I might turn on the home cinema in a short while and just loop the scene with only the four-channels of the surround on, to see what else is within that part of the mix that I can toy with.

 

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Well I've just started the film up the warmness of the strings and strange types of sound effects is nice, when it gradually starts to slowly build up with crashing sound of strings and percussion it's felt on the four-channel surround array. As the main title comes up on the screen SPL and frequency response is down to 25Hz mostly peaking around 40Hz and 63Hz. With SPL @96dbc and 80dba, so it's not too bright sounding on the surrounds yet!


The crane sequence is all around me and overhead!



You need to place the surrounds on your side and rear wall not too high up, mine are only placed at 64 above the floor while the two overhead surrounds are placed at 97 off the floor that is the front of the baffle is.


Each of the sidewall surrounds have there own EQ, while the backs and overhead work off a second EQ. sub bass extension is derived from the Pioneer VSP-200 Dolby pro-logic decoder low pass output.


That storm picked up to103dbc it seemed real enough, but I know the technical limits of the JBL control 1 and while most of the THX spec says there shouldn't be any distortion, there wasn't so I was a shy under 105dbc.


At 15m 06s on the region 2 DVD the strike hits @85dba while @100dbc for all the sub bass mid bass and highs, 88dba at 15m 17s it was louder than normal speech!


I do have options to turn the fader down from (0db) where I would normally set the fader at lower level if the films soundtrack is really over the top, which is the case for War of the Words, with the fader set at -7db and at 15m 17s it came in @80dba which seemed a little more comfortable.



There's nice low level of wind blowing when farther and son play in backyard, but that wind will soon pick up!


Sub bass on the surrounds can at times super evasive!
 

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Discussion Starter · #14 ·

Quote:
Originally Posted by cherry ghost /forum/post/0


How far apart will they be from each other in the two options? If possible, you want to maintain the proper angles.


Judging by the picture, I think the second option of 8-9 feet back has closer specs to the angle required. If I place the back speakers 2-3 feet, the angle is too wide in comparison to side surrounds.
 

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Quote:
Originally Posted by psychdoctor /forum/post/0


Judging by the picture, I think the second option of 8-9 feet back has closer specs to the angle required. If I place the back speakers 2-3 feet, the angle is too wide in comparison to side surrounds.

You are right. Actually you can spread them a little further, if possible place them about 9.5-10.5' apart.
 

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JBLsound4645 said:


It's ran just like any normal commercial cinema that I have worked at in the past, only this time I'm taking it to a newer level of playback in the home.

I have played the same scene from War of the Worlds many times over, even with the three-screen and LFE.1 turned off, where only the sub bass extension is used along with the split-surround array.

Of course you have more surrounds than any dubbing stage I've worked in - perhaps a different type of speaker would allow you to cut down on the number you're using. But with your present setup, you should check out "We Were Soldiers". Although not really advertised as such, it was mixed with an overhead channel matrixed. Be interesting to hear how that sounds in your setup.
 
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