I have been working from the following spec for my ht design re: speaker placement

http://i147.photobucket.com/albums/r290/LewisCobb/Home%20Cinema/Dolby_7.jpg

Here’s a layout plan of my room at the moment -

http://i147.photobucket.com/albums/r290/LewisCobb/Home%20Cinema/speakerplacement.jpg

I am planning on 2 Rows of Berkline 090 seating, 2 seats in the front, 3 in the rear. Rear is against the wall – bad situation I know - but you work with the room you have and do the best you can so I am optimizing the front 2 seats (the most often used) for acoustical purposes while hopefully not creating a “mess” for the rear row. If I had to choose which rear row seat would be used the most it would be the center one and the ones on each side being used far less.

The surround and rear speakers are almost in ideal places based on the Dolby spec. and I have been considering the Axiom line of speakers for my theater so I am trying to decide between– either the QS8s – which are di(bi?)polar and the inwall/on wall hybrids.
QS8s here – http://www.axiomaudio.com/surroundspeakers.html
In Wall/On Wall Hybrid Here - http://www.axiomaudio.com/wallspeakerw3_main.html

Thoughts from the experts here? I think I can fit the inwalls underneath my fabric frame treatments and thereby hide all the speakers in this room, but the di(bi)polars would have to be exposed. There are “style” arguments to be made for both approaches but I’d like to know what’s the best speaker acoustically for this room layout. The theater is dedicated for movies – it will never be used as a “listening” room.

Thanks very much.
Lewis

Why couldn't you hide the qs8 in columns? Looks like you have the room if you built them slightly behind the first row?

Personally, I'm going to use my qs8's on the side and get direct firing speakers for the rear. The hybrids (or normal bookcase speakers) would fit the bill.

Hi -
I can't really do columns - I have already created column like structures that are hiding a door on the right side and access to pipes on the left of the theater. You can see them ahead of the front row on the left/right. I am planning on either "hinged" columns as shown, or some velvet curtain arrangement like at the back entrance to the theater that will open to reveal the door and pipes behind. In between the columns and the front/back of the theater I will place fabric frames that hide the acoustical treatments for first reflection points as well as the standard "around the room at ear level linacoustic treatment".

Here's a render of my plan that shows the QS8s on the sides and rear and you can see the "hinged column" concept midway between the back wall and the stage. You can see the QS8s are a bit "in your face" for the poor lads sitting on the ends of the rear row :( .

http://i147.photobucket.com/albums/r290/LewisCobb/Home%20Cinema/CinemaRoom-CurtainsInRear.jpg


Your idea on the QS8s on the side and hybrids on the rear is something I had not considered. May I ask what your reasoning is for this? Why not all the same ? Space restrictions or some acoustical reason ?

I have to admit that with all the reading I have been doing my head is spinning on the Dipolar/Monopolar speaker issues and their proper placement.



Why couldn't you hide the qs8 in columns? Looks like you have the room if you built them slightly behind the first row?

Personally, I'm going to use my qs8's on the side and get direct firing speakers for the rear. The hybrids (or normal bookcase speakers) would fit the bill.

Hmmmm.....another 4 hour stretch of reading in here and on the speaker forum and I realize that I am a little off base in describing the QS8s as dipolar - they are it seems quad polar with all speakers firing in phase - from sides and top/bottom. Given this new found knowledge - it would appear that the QS8 will give a more widely dispersed sound field and more forgiving of placement errors than the monopole ..... and in no way creates a "null" zone in the pattern.....

When buying speakers, I always ask the store for an in home audition. If I buy them I ask for an upgrade exchange policy, you'd be surprised how many dealers offer these services.
From your sketch, the back row of seats seems a bit too close to the back wall. Also, I wouldn't put the middle seat directly on the center line.

Hmmmm.....another 4 hour stretch of reading in here and on the speaker forum and I realize that I am a little off base in describing the QS8s as dipolar - they are it seems quad polar with all speakers firing in phase - from sides and top/bottom. Given this new found knowledge - it would appear that the QS8 will give a more widely dispersed sound field and more forgiving of placement errors than the monopole ..... and in no way creates a "null" zone in the pattern.....

Yes, because they create such a dispersed sound field they make great surrounds. As for rears, I think the idea is to have the sound more localized (coming from behind you). This is better done with direct firing speakers. Anywho, I'm hardly the expert, but it's the direction I'm heading in.

Yes, because they create such a dispersed sound field they make great surrounds. As for rears, I think the idea is to have the sound more localized (coming from behind you). This is better done with direct firing speakers. Anywho, I'm hardly the expert, but it's the direction I'm heading in.

Cathan -
I read that as well, but then on the Axiom site they are peddling the QS8s as all four speakers - surround and rear. They have the architectural (inwall/onwall) series as well which are more direct firing so it's not like they are trying to sell the only speaker they have for surround/rear. I am going to flick them an e-mail on this and see what they respond with - they are very responsive based on the limited interaction that I have had with them to date. I'll post up the reply when I get it.

Winkleman -
I hear you on the rear row being close to the back wall. I am pretty much forced into this situation if I want the Berk 090's and 2 rows and still have a reasonable sized screen (96" wide) as the riser has to be 6' minium depth from what I have learned from the seating guys. I might be able to pull them out about 6"more but then people could be kicking the rear of the front row seats (or worse, someone's smelly feet are right by your ears..... :eek: )I'm curious about the center seat issue though - is this a problem due to the room modes being at a peak in the dead center of the room left/right? I am not sure I can shift things that much left/right - maybe only a few inches with this present layout.

Thanks for the advice fellows. I appreciate it.

I'm not an expert either but direct firing in the rear is my plan as well for my 7.1 setup with diploes on the sides. From what I understand it is harder for us human types to localize sound from behind. Direct firing speakers help us localize the right/left coming from the rear.

Andy

harder for us human types to localize sound from behind. Direct firing speakers help us localize the right/left coming from the rear.
You cannot have it both ways. :)

In any case, movies are not mixed with any form of localization in the rear of the theater. (Nor on the sides, for that matter.)

You cannot have it both ways. :)

In any case, movies are not mixed with any form of localization in the rear of the theater. (Nor on the sides, for that matter.)

Well then - sounds to me like QS8s all around then. They certainly seem to be the ticket for better envelopment and perhaps a bit more forgiving as far as placement goes. Placement flexibility will help with the interior design police as well :)

Thanks for the input Dennis.

Lewis

I'm not an expert either but direct firing in the rear is my plan as well for my 7.1 setup with diploes on the sides. From what I understand it is harder for us human types to localize sound from behind. Direct firing speakers help us localize the right/left coming from the rear.

Andy

My other thought for using direct firing speakers in the rear is that I think that the columns will be easier to build. I still haven't noodled through how I'm going to build columns around the fact that the axioms fire up and down as well as side to side.

Anywho, I don't think you can really go wrong with either approach.

In any case, movies are not mixed with any form of localization in the rear of the theater. (Nor on the sides, for that matter.)

Hmmm....I think I understand what you're saying, but I'm not sure I understand how it should drive a speaker selection.

I am also looking at using dipoles or side surround and directs for rear; do you believe this is a good choice, or does it really matter for the rears?

My other thought for using direct firing speakers in the rear is that I think that the columns will be easier to build. I still haven't noodled through how I'm going to build columns around the fact that the axioms fire up and down as well as side to side.

Anywho, I don't think you can really go wrong with either approach.

That's the impression I am getting the more that I think about this issue and the more reading that I have been doing. You're right though on the up/down issues with the QS8s - It looks to me that the use of these in columns might be a bit risky for that reason - unless of course the column is just a U shaped piece of GOM over a skeleton framework and does not have any substance to it like the MDF versions people are building.

Hmmm....I think I understand what you're saying, but I'm not sure I understand how it should drive a speaker selection.
The surround effects channels as mixed for movies (and in reference mix stages) provide a diffuse sound field over a wide area. Monopoles cannot do that with less than about 15' between you and the speaker. If you can localize the speaker, you've missed the mark

The surround effects channels as mixed for movies (and in reference mix stages) provide a diffuse sound field over a wide area. Monopoles cannot do that with less than about 15' between you and the speaker. If you can localize the speaker, you've missed the mark

Ok - that makes sense. Thanks for the response.

The surround effects channels as mixed for movies (and in reference mix stages) provide a diffuse sound field over a wide area. Monopoles cannot do that with less than about 15' between you and the speaker. If you can localize the speaker, you've missed the mark

Any yet another example why it pays to read this forum for at least a year before starting to build. I swear I learn something new every single day I spend surfing this forum.

/mentally redesigns his theater yet again...

My other thought for using direct firing speakers in the rear is that I think that the columns will be easier to build. I still haven't noodled through how I'm going to build columns around the fact that the axioms fire up and down as well as side to side.

Anywho, I don't think you can really go wrong with either approach.

I seem to remember someone here in the forums that did build a column for the QS8's. I just can't remember who.

Hey, you out there? Who are you? :D

This (http://www.thx.com/library/pdf/THX_HT101-011906.pdf) is kinda interesting - very simplified but covers most points (for thx anyway). Speaker diagram on pg 15 looks like what I'm planning on doing except my rears will be apart and all front will be behind a 2.35CH SMX screen. :)

Andy