Axiom Home Page Forums General Discussion Home Theater QS8s as Rear Surrounds?

Saying that "movie sound engineers mix them to be filler sound and atmosphere rather than precise" is not a hard-and-fast rule. For example, movies like Gravity do have precise and discreet audio going into the surround speakers. There are many scenes where the actors are talking (in their spacesuits) while the camera is panning around. The audio of their voices moves around all the speakers so their voices match their position (both on and off camera), and the effect is quite stunning.

The second rule you mentioned I consider a general guideline and is often not feasible in many living rooms, and plus the design of the QS4/8 makes them somewhat forgiving and flexible regarding their placement. The average person's ears are roughly 3' (plus or minus several inches) above the ground while seated comfortably on the couch. Obviously this number varies depending on the height of the person, type of furniture, posture, etc, but let's just use 3' as a nice round number. That 2'-3' rule you mentioned would mean that the surrounds would have to be 5'-6' above the ground. Of course the surrounds also have to be at the proper angle behind the listening position. Unless you just happened to have equidistant walls that allowed you to mount the speakers at both the proper height and angle behind the LP, you would either need very tall speaker stands or the speakers would have to hang down 3'-4' from a 9' ceiling, which in both scenarios would look unacceptable to many people (and all wives ). I've got my QS8's hanging down from the ceiling about half a foot and angled downward toward the LP. When playing a movie at louder volumes (the higher volumes all home theater enthusiasts watch their movies at ), the sound bouncing off the ceiling along with the quadpole effect creates a wide soundstage that you can't tell are coming from speakers 5' above you.

FWIW I'll be removing my rear surrounds and placing my QS8's across the rear corners of my room (idea came from Imax video I watched).
They've sounded good in every position I've ever placed them and have little concern it will not work out for the best.
My front sound stage is competing with my side surrounds in the 7. configuration.

I would echo John's comments here.
If that back wall is truly that far back, a direct radiating speaker will have less of a prominent localization than if they were much closer to the listening seats (try placing two speakers, side by side, 10 or more feet away, switch sound from right to left and see if you can really tell which is right and left...gets harder with increasing distances).

That being said, if you already have QS8s on the sides, sticking with the same for the rears is a safe and good option.

Every mixing studio I've seen pictures of uses direct radiating speakers. I am sure that there are some out there somewhere using di/bi/mono/quad pole speakers though.

Also, Dolby (or was it DTS) DID put out pictures somewhere (it has been some time since I used it for reference since my theater build out and wiring was done a few years ago), but the still said that for 2 row to put the side surrounds 90 degrees from the front row, assuming that the front row is your primary seating. There was never an explanation that I saw or read as to if you normally sit in the second row.

You state that in one post, follow Dolby and DTS, and then in the next just give your opinion....

Just saying....

For my setup, the speaker placement is quite good. I am always just looking for that extra little "tweak" to make it better, and to go back to my original reply, I just said that I would have loved to compare direct radiating vs quadpole when I was setting things up just to see which I lived better instead of just assuming that the QS8s were the way to go.

Also remember that in an "ideal" world, all speakers would be the exact same, fronts, center, and surrounds. That has been the "ideal" for a long time, but just something hard to obtain financially for most, and difficult to do speaker placements as well. Mixing studios use direct radiating and many times the exact same speaker model for all speakers in the room.

Thanks for the good debate. Please understand that I am not attacking you or anything, just offering up some discussion. I only mention that since you are pretty new around here and together we will share ideas and insights that may help someone.

MK Speakers were the most commonly used speakers for Surround Sound Engineers in the Studio.
Here is a link for their Speaker Setup recommendations:

http://mkloudspeakers.com/pdf/MK-Speaker-System-Manual.pdf

Page 7
"HEIGHT
The surround speakers should be located relatively close to the ceiling. Placement above the listeners’ heads is important, preferably with the cabinet’s bottom at least two feet (60 cm) above a seated listener’s head. In fact, it is even better if the speakers are located above standing listeners’ heads, about 6-7 feet (180 – 210 cm) above the floor for times when listeners are standing or walking around the room."

Page 9
"SURROUND CHANNELS
You can achieve good performance with your surround speakers placed in a wide variety of room locations. In general, they should be either to the sides of or behind the main listening position, located higher than the listener’s heads. They can be mounted on either the side walls or on the back wall, flush to the wall, on shelves, on brackets, etc.
The goal is to achieve an enveloping sound. The surround channels should seem to come from all around you, rather than seeming to come from behind you only or directly from a speaker. For non-THX surrounds, we recommend starting with speakers on the side walls of the room,
two to three feet (60 – 90 cm) above the listeners’ heads"


Here's the Reference to Dolby Labs Speaker Placement:

http://www.audioholics.com/home-theater-connection/home-theater-speaker-layout-an-essential-guide

"The main left and right surrounds should be to the respective sides of the listening area, above ear level if possible (ideally 2 feet or more) at an angle of 90 to 110 degrees"


ps: I may be new to this Forum but i've been discussing A/V now for over 20yrs and stay up to date. My earlier posts were from my cell phone as I usually give FACTS with LINKS to back it up. But I was just going from memory earlier.

I knew I would hear a Strawman Argument to say that they knew of a movie which had a scene using Precise Surround Sound Effects. However as we all know 99.9% of All Movies use surrounds as FILLER & ATMOSPHERE. Even Gravity which still uses mostly Atmosphere to engage the viewers except during a couple quick scenes where they try to be precise. What you don't do is set-up a system for an Anomaly that happens very seldom.

Second the reason I said ear height and not 36" is because not everyone is the same size and if your trying to be Optimal in your Set-up you would adjust accordingly to your personal preferences.

Unless that's what the director intended.

I see all of these rules as general guidelines like the default 80 Hz crossover point. The people who can actually adhere to all of them are going to be an anomaly themselves.

some 2 years ago, when it came time for me to get surrounds, i bought 2 QS8s and then tried them for a while when setup as side surrounds.

later on, time came for the rear surrounds and i found an old pair of R.S. Minimus 7 speakers i had.

i mounted them about 8-9 ins. from the back wall, with the drivers facing the back wall at a small outward angle of about 15 Deg.

this makes the back surrounds work partially as direct radiating when the program calls for it, and also partially as diffused surrounds when needed.
The QS8s might be better doing this than my Minimus 7s, but the result is very satisfying for me.

+1

If you can adhere to the strict guidelines of the Dolby or other speaker layout recipies out there that is great.

The Manufacturer is also a great reference when determining where their speakers are appropriate.

For most people without no holds barred dedicated and planned rooms, the best we can do is often more than good enough to enjoy the experience. In the end thats all that matters.

First off most people can easily mount their Surround Speakers properly at 2'-3' Feet above their listening position regardless if their Direct Radiating or a Diffused Speaker. Because just mounting their Surrounds higher will create a more proper diffused sound as intended.

Second what percentage of movies use surround sounds directly vs diffused?
I see that their are some people on here still ignore this FACT.
The huge majority of movies (99%) use surrounds for Atmosphere (diffused), Which is why if your setting up for an Anomaly (direct), then you will be greatly depreciating the Accuracy of the sound stage and misrepresenting what most Sound Engineers are trying to accomplish.

You don't need special speakers or tons of money to properly place your speakers in an ideal location to accomplish having Diffused Sound. That's like saying it doesn't matter if you face your center channel backwards or forward. This is proper speaker placement. I'm sure I could even find a movie scene where a reversed center channel could be beneficial but that's just silly.

As you should know every 6dB is a perceived Doubling in Sound to the human ear. http://www.sengpielaudio.com/calculator-levelchange.htm

So if your using the QS8's you should be using a 95hz Crossover, however most receivers will not let you be that accurate so using either 90hz or 100hz should work fine. I personally prefer the 100hz Crossover because it has a Flatter Tighter Freq Resp of (+/-3dB)
While a 90hz Crossover brings your Freq Resp up to (+/-5dB). Which is not a good thing if your going for a FLAT FREQ RESP.

This is why Paradigm speakers another Canadian Manufacturer uses such a tight Freq Resp on all of their Specs that's (+/-2dB) instead of Axiom which standards are (+/-3dB) which allows Axiom to cheat their loudspeakers specs thus achieving lower ratings for their low frequencies of their speakers.
So next time you look at specs between different companies keep in mind that sometimes the Loudspeaker that says it can play lower can be misleading if you don't understand the fine print.

Don't get me wrong i'm a huge fan of both companies which is why I own Axiom QS8's in the first place.