5.1 rear speaker placement in two row theater? - AVS Forum
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post #1 of 9 Old 12-04-2007, 07:18 PM - Thread Starter
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Hi all,

Been searching, found some similar topics but not quite my scenario.

I am going to have 2 rows of seating in my 15' 6" long room. First row will be about 8 feet from screen, 2nd row seats about 5 feet behind.

I am looking to wire for 7.1, but will initially only have 5.1. I have seen some info that says for dipolar speakers and 2 rows of seating, put the rear surrounds between the 1st and 2nd rows.

I am going to be going with quad polar (axiom QS4) speakers mounted from the ceiling.

1. Should these go in the same spot as dipolars - between the 1st and 2nd rows? Due to the length of my room I really have no choice but to do this - assuming I eventually put the 7.1 speakers on the rear wall.

2. With the rear surrounds in front of the 2nd row, what will the listening experience be like when sitting in the 2nd row? Do you still get the 'surround' effect?

3. Given that my 2nd row will only be a foot or 2 from the rear wall, will a 7.1 setup even work well for me or will the 7.1 speakers on the rear wall be too close to the back row (same axiom qs4 on rear wall)?

Thanks a lot for the input.

Darren
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post #2 of 9 Old 07-15-2013, 02:27 PM
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Regardless of the type of speaker, I've always read that the surrounds (side) should go at 90 - 110 degrees of the listening position - which is to the side or slightly behind but not in front of the listening position. If you put them between the rows, they will be in front of the rear row. I would think you should put them to the sides of the rear row so they are 90 degrees for the back row and slightly more than 90 degrees for the front row as suggested.

I have my back surrounds on the rear wall that is also very close to the listening position - I know it is not ideal but I kept them fairly close together so I didn't get too wide an angle between them and I am happy with how they sound there and blend with the (side) surround speakers (same speakers for all 4 positions). Mine are dipole Def Techs so I get a little better dispersion that the average direct firing speaker. I don't have that much 7.1 content yet, so I don't always get to hear them anyway.

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post #3 of 9 Old 07-15-2013, 04:27 PM
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Originally Posted by pheare View Post

Should these go in the same spot as dipolars - between the 1st and 2nd rows?
That's not where dipolars should go, instead they're intended to be placed directly to the sides of the main listening position, whether that is your 1st row or 2nd row.

Dipoles are unique in that they create a null (quiet zone) directly to the side of the speaker, so that listeners hear very little direct sound and are instead enveloped by reflected sound. Placing them between rows means that none of the listeners are in the null. If you're not going to make use of this unique feature of dipolars, then why use them to begin with?

Do you know whether the Axiom speakers you're considering have a dipole or bipole radiation pattern? If not, can you find out from the manufacturer?
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Originally Posted by pheare View Post

Given that my 2nd row will only be a foot or 2 from the rear wall, will a 7.1 setup even work well for me or will the 7.1 speakers on the rear wall be too close to the back row (same axiom qs4 on rear wall)?
With the 2nd row being a foot or 2 from the rear wall, there will hardly be any rear-vs-side separation in the surround field to make 7.1 worthwhile. However, it is entirely different for the 1st row, which will be several feet away from the back wall and will yield excellent separation.

BTW, when you calibrate levels and distances, will you be doing that from the 1st row or 2nd row or somewhere inbetween?

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post #4 of 9 Old 07-16-2013, 09:19 PM
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Quote:
Originally Posted by sdurani View Post

That's not where dipolars should go, instead they're intended to be placed directly to the sides of the main listening position, whether that is your 1st row or 2nd row.

Dipoles are unique in that they create a null (quiet zone) directly to the side of the speaker, so that listeners hear very little direct sound and are instead enveloped by reflected sound. Placing them between rows means that none of the listeners are in the null. If you're not going to make use of this unique feature of dipolars, then why use them to begin with?

I personally run QS8's and have a similar seating arrangement. I would disagree that you want the speakers mounted directly beside the listening position. Bi polar, di polar, and quad polar speakers all have their individual characteristics. I found the QS8's blended best when mounted slightly behind and above the listening position. I have mine almost dead center between the first and second row, and it creates a nice effect in either, without calling attention to themselves. The soundstage is a hair further forward for the back row, but much better than when I was running a direct radiator.

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With the 2nd row being a foot or 2 from the rear wall, there will hardly be any rear-vs-side separation in the surround field to make 7.1 worthwhile. However, it is entirely different for the 1st row, which will be several feet away from the back wall and will yield excellent separation.

I agree with this to some extent, but not entirely. Due to the fact that the second row has the surround mounted in front of them, you will definitely see some improvement with rear surrounds. When I have the rear surrounds off, the surround stage pulls forward of the rear seats a bit. When I engage the rears, the entire sound field is much more enveloping and seamless.

If you were running only one row of seats, and that row was against a rear wall, I would totally agree the rears are not worth it. This is not the case however and I would move forward with them. I was running QS4's, then 8's in the rear and was fairly happy with them. I just switched them out for M2's recently as I changed out my columns; and I prefer the direct radiators for the rears. YMMV.
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BTW, when you calibrate levels and distances, will you be doing that from the 1st row or 2nd row or somewhere inbetween?

If using Audyssey, it is recommended to calibrate the center of the front seats first. Aud will base all information off of this position and tailor it from there.

Here's a pic of my side and rear placement.




My gosh. I just realized this thread was started back in 07. What possessed you to respond to a 6 year old thread. cool.gif

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post #5 of 9 Old 07-16-2013, 09:39 PM
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Originally Posted by bass addict View Post

I would disagree that you want the speakers mounted directly beside the listening position.
If you're not going to place listeners in the dipole speakers' nulls, then why buy speakers with such a unique feature?
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Due to the fact that the second row has the surround mounted in front of them, you will definitely see some improvement with rear surrounds.
Then why not have this improvement for the primary listening row (1st) rather than the overflow row (2nd)?
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If using Audyssey, it is recommended to calibrate the center of the front seats first.
If you're going to compromise side speaker placement to accomodate both rows, why not do the same when calibrating with Audyssey? You can't simultaneously care and not care about the 2nd row.
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What possessed you to respond to a 6 year old thread. cool.gif
The post 2 hours before my response.

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post #6 of 9 Old 07-16-2013, 10:47 PM
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Originally Posted by sdurani View Post

If you're not going to place listeners in the dipole speakers' nulls, then why buy speakers with such a unique feature?

A few reasons. QS8's are a quad polar design as I'm sure you know. I know from experience that I get better surround effects mounting them slightly behind the listening position. I did not like having them beside the seats (the null was counter productive to their design and intended placement, IMO)

Unless you are running a set of surrounds for each row, you will have to compromise. QS8's are able to hit both rows equally well, providing for a well balanced surround.
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Then why not have this improvement for the primary listening row (1st) rather than the overflow row (2nd)?
If you're going to compromise side speaker placement to accomodate both rows, why not do the same when calibrating with Audyssey? You can't simultaneously care and not care about the 2nd row.

True. But that's effectively what you are doing to an extent. My main calibrations (FR, etc), are for the LP, but I have also taken into account numerous seats. In my room I'd prefer to have a less than perfect MLP and everyone else have an enjoyable experience; than tuning exclusively for the MLP and having everyone else suffer.

My comment about Aud was that speaker distances, reflections, etc;, should all be based off the first row center point in your room. If you put the mic at a seat other than the center, it can cause improper measurements according to Audyssey.
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The post 2 hours before my response

That actually was directed to the poster above you. smile.gif

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post #7 of 9 Old 07-17-2013, 10:36 AM
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QS8's are a quad polar design as I'm sure you know.
Actually I don't know what that means, which is why I asked if they have a bipole or dipole radiation pattern.
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I did not like having them beside the seats (the null was counter productive to their design and intended placement, IMO)
That was my earlier point: considering the incredibly tiny percentage of speakers that have an acoustic null in their design, why deliberately buy speakers with a null if you aren't going to use the null? Something wrong with buying multi-pole speakers that don't have a null?
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But that's effectively what you are doing to an extent. My main calibrations (FR, etc), are for the LP, but I have also taken into account numerous seats. In my room I'd prefer to have a less than perfect MLP and everyone else have an enjoyable experience; than tuning exclusively for the MLP and having everyone else suffer.
Guess this boils down to two choices: optimize one row and compromise the other vs compromise both rows. In both scenarios, one row is going to be compromised anyway. Which means that the difference really boils down to having the main row optimized or compromised. Given that choice, I wouldn't pick the latter when I could have the former.

To that end, I would make my first Audyssey measurement (to set levels & distances) from the main row rather than somewhere between both rows. Following that logic, I would set up my side speakers for that same row rather than both rows. That doesn't mean that the second row will sound bad (listeners will "suffer"), just means that it won't be optimized. But that was going to happen in either scenario.

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post #8 of 9 Old 07-18-2013, 02:39 PM
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Originally Posted by bass addict View Post

My gosh. I just realized this thread was started back in 07. What possessed you to respond to a 6 year old thread.
Was looking for a discussion on this exact topic and thought I would reply to an unanswered question instead of posting my own - seemed like a very relevent topic.

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post #9 of 9 Old 07-18-2013, 06:30 PM
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Originally Posted by mtn-tech View Post

Was looking for a discussion on this exact topic and thought I would reply to an unanswered question instead of posting my own - seemed like a very relevent topic.

I'm confused; were you looking to ask a questions or provide an answer?

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