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Please help me decide where to place my Di-Pole/Bi-Pole surrounds (1 Viewer)

Sadanorakman

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Just finishing converting my single garage into a home cinema, and need to decide where to fit my L and R surrounds… seemingly a simple question, but of course there are constraints…

I’m cabling for 5.1.4, but initially installing 5.1 until I can afford to replace my current amp and buy four matching in-ceiling speakers.

Because it was a flat roofed garage, the ceiling is now only 7ft high after insulating the floor for building regulations. This means that my L/R surrounds need to go only one foot above ear-height to allow for some vertical separation to the atmos ceiling speakers (2.5ft). The front LCR are just below the projection screen, so there will be much more vertical separation for the atmos there (4ft).

7.1.4 is out of the question, as the couch is (almost) up against the rear wall, and when I’ve tried 6.1 and 7.1 over the years, I’ve never appreciated the back surrounds at all, and always returned to a 5.1 set-up.

In 15 years, and four different houses, I’ve always used direct radiating L/R surrounds, and generally feel that they draw too much attention to themselves (even when set up with audyssey XT32) , so would like to use something more diffuse this time: I can therefore either put Di-Poles to the sides (position A in diagram), or bi-poles behind our heads (position B in diagram). Third choice would be to place a pair of very small satellites (MA Radius 45’s?) on stands behind the couch, but firing at the side walls to reflect their sound back at the listening position.

Surround placement.jpg

I know Di/Bi-poles are becoming less popular these days, and atmos is supposedly meant to be used with direct radiating speakers, but if I have direct radiating L/R Surrounds so very close to the listening position, I just know they are going to stand-out like a sore thumb in the mix.

I’m planning to use Monitor Audio Bronze speakers all round, with their Bronze FX’s as the L/R surrounds switched to either Di-pole or Bi-pole as discussed above, unless someone can think of a better idea?


Many Thanks
 
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Sadanorakman

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Was hoping someone had tried bi-polars just behind listening position as L/R surrounds, and could offer some advice. Anyone please?
 

Sadanorakman

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Thanks Stephen_J_H, much appreciated. I've been off and read the audioholics article with great interest. They clearly do not like di-poles at all, thinking that they are simply too diffuse in their nature.

I posted this exact thread on avforums too, and Ironically, a guy there who has a very similar narrow single-garage conversion is using di-poles to the sides with great results! He started with them high, and has since lowered them to 1ft above head-height, as he has implemented atmos.

So I made the mistake of mentioning it to the missus this morning, and she asked me to show her where the speakers would go.... of course, she much preferred them tucked-away on the rear wall symmetrically about the window-frame.

So a bit of back-of-a-fag-packet, psuedo-science:

I've measured up more accurately, and drawn the following to scale. I then (very roughly) projected narrow beams from each tweeter to approximate the dispersion of a high frequency sound (say a bird tweet of 5-8Khz) that would normally be very easy to localize from a direct radiating surround speaker (the higher the frequency, the narrower the radiating pattern of a sound from a driver).

If driven in Bi-pole mode, then this speaker layout seems to give a pretty reasonable surround channel positioning for each of my three listening positions.

If you look at it from the perspective of each individual listener's ear positions, then the outside seats should hear more of the reflected tweeter on their respective side, as the other tweeter fires past their head, yet more direct sound from the tweeter of the opposite surround speaker (mixed with some reflected sound). Hopefully this will go some-way to evening out the listening distances/volumes of effects for each of the three listening positions...

What do you guys think? am I applying bad logic here?:
Surround placement 3.png
 

Stephen_J_H

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I must admit, it's more effort than I would've put in, but the logic seems somewhat sound, pardon the pun.
 

Sadanorakman

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Thanks Stephen_J_H. Unfortunately I was having to install the cables before being able to buy the speakers, which I realise isn't very sensible, but needs-must.

Now I'm agonising over the choice between Monitor Audio Bronze and Silver speakers. I don't want to spend so much for the Silver, yet in comparison to the bronze, they have lovely real wood veneer, and I'm sure would also be a step-up in sound quality! It's adding the four ceiling speakers that changes the pricing dynamic between bronze and Silver, if anything making the Silver package better value for money!
 
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