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Discussion Starter · #1 ·

 


 

So, aside from the center channel, I've been wondering if this is a good idea?


The setup doesn't deviate that much from the Dolby recommendation. 



 

Once I finally decide which speakers I am going to purchase, I'll most certainly tinker around with the concept (mainly I'll experiment with the height of the rears/surrounds while maintaining symmetry).  I guess my main questions is:  Has anyone tried this particular arrangement & if so would you be kind enough to share your experiential knowledge on the matter?


Oh, I almost forgot!  I was wondering about aiming the rears/surrounds at where my ears are going to be.  Is this recommended?  I figure that since they are spatially elevated then they should appear to be so.  I don't really think aiming the left & right surrounds directly at each other makes any sense whatsoever.  I'd prefer they be...  toe-down?  would that be ideal?

 

Also, I'm working within a pretty tight space limitation.  There are 7 feet between the front & rear wall.  The left & right walls are 12 feet apart.  In any other situation, this lengthwise setup would probably not be recommended.  However, in this particular space, the resonant bass frequencies are all but completely eliminated by positioning the sub dead center on a side wall & listening from the center of the room, facing a long wall, on the floor.  I'll upload the analysis from REW shortly, though I doubt anyone really cares that much...  ANYWAY!  Considering the space limitations I was contemplating the use of height (regarding surround/rear speaker placement) to compensate.


Should the rears & surrounds be placed on the same plane (horizontal) or can I place the rears (substantially) higher than the surrounds?

 

Thanks!


 
 

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Discussion Starter · #2 ·

When the 7 foot wall was my front wall, this was the best I could get from my sub.

 



 

A couple weeks later, I was surprised to discover this




Anyway, I said I'd post that stuff from REW, so I did.  Isn't really on topic though...
 

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Quote:
Originally Posted by morphemes  /t/1524022/7-1-setup-using-equilateral-triangles#post_24521632


Has anyone tried this particular arrangement & if so would you be kind enough to share your experiential knowledge on the matter?
I've a set-up like that since 1991. Your seating being 3.5 feet from the back wall is cutting it close as far as getting meaningful separation between your side and rear speakers.
Quote:
Originally Posted by morphemes  /t/1524022/7-1-setup-using-equilateral-triangles#post_24521632


However, in this particular space, the resonant bass frequencies are all but completely eliminated by positioning the sub dead center on a side wall & listening from the center of the room, facing a long wall, on the floor.
That placement only eliminates the first height resonace at 71Hz and first length resonance at 81Hz. But, placing a subwoofer against a side wall is going to energize all the room resonances across the width of the room. In your 12-foot wide room, that means a big null at 47Hz and a big peak at 94Hz at the midpoint of room width (where you plan on sitting).
 

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Discussion Starter · #4 ·

Quote:
Originally Posted by sdurani  /t/1524022/7-1-setup-using-equilateral-triangles#post_24521779



I've a set-up like that since 1991. Your seating being 3.5 feet from the back wall is cutting it close as far as getting meaningful separation between your side and rear speakers.

That placement only eliminates the first height resonace at 71Hz and first length resonance at 81Hz. But, placing a subwoofer against a side wall is going to energize all the room resonances across the width of the room. In your 12-foot wide room, that means a big null at 47Hz and a big peak at 94Hz at the midpoint of room width (where you plan on sitting).
Well, the "meaningful separation" is kind of what I was interested in figuring out.  I can't imagine sound engineers actually mastering soundtracks with the intention that these channels are to be positioned off axis, but I don't know.



The simulation has me sitting two feet ten inches from the front wall, just about dead center. Here's a couple charts of how the room actually sounds (using a somewhat crap pair of speakers & a Polk PSW505).




 

a null at 47 isn't really a bad thing in this room.  It rings 47 in pretty much every configuration I've tried (except this one) & the peak around 94 is quite tamable & it helps to have enough space to my left & right to actually trap it.   According to the simulation, 94 is the only problem.   According to the measurements, Audyssey took care of it already.

 

More interested in finding the right speakers for the time being...
 

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Quote:
Originally Posted by morphemes  /t/1524022/7-1-setup-using-equilateral-triangles#post_24521892


I can't imagine sound engineers actually mastering soundtracks with the intention that these channels are to be positioned off axis, but I don't know.
Not sure what you mean by channels "positioned off axis", but the idea is to separate sounds at your sides from sounds behind you. Nothing more complicated than that.
Quote:
Originally Posted by morphemes  /t/1524022/7-1-setup-using-equilateral-triangles#post_24521892


a null at 47 isn't really a bad thing in this room.
Not with those speakers, but it will be different with a subwoofer that energizes the low frequencies more strongly. The null can be cancelled with a second sub placed opposite the first sub.
 
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