Axiom Home Page Forums General Discussion Advice from Axiom Owners HT Room - Advice on Speaker Selection and Layout?

That is a great question. Since the room isn't very deep (front to back), it doesn't allow for a lot of separation between surround speakers and the overheads.

One thing to consider is that you have 5 seating positions that are sideways. Those will be compromised in all sorts of ways if used for movie watching. I would cater the sound more to the main 6 person seating in the back. That is where a bulk of the movie watching will happen. In fact, I would be tempted not to worry about the sound for those seats at all. If you end up having a lot of people over to watch a movie, and you turn those other seats towards the screen, they will have to be far off to the sides so that they aren't in the way of the main 6 person seating, so no sound field is going to do well for those areas.

So if you go 5.1.4, then you should move your side surrounds further away from the screen, and bring your in-ceiling speakers closest to the screen back as well.

If you go 7.1.2, then the surround placement is OK. I would rather see the side surrounds closer to the main seating side of the room, especially since it would put the 2 in-ceiling speakers in front of the listening area anyway.

Here are some initial rough ideas about a 5.1.4 and 7.1.2 layout for your space with focus on always playing things back in either Atmos, DTS:X, or one of their upmixers. These layouts will provide room filling sound, good separation for Atmos/DTS:X overhead speakers, and still be closer to regular standards. I tried to keep your limitations/compromises in mind, but may have moved something to a location that would be a placement issue physically for you too. Only you will know that. I also did NOT touch the subwoofer placements.

I apologize for their crude look. I just did copy/paste/erase of things that you had vs. recreating the speakers that you have drawn up.

Thanks, that all makes a lot of sense! Couple more Q on what layout to choose?
- 5.1.4 vs 7.1.2 : Given my collection is almost all Blu-ray (without Atmos/DTS:X) would 5.1.4 make better sense for backward compatibilty.... or am I missing something?
- Also I'm thinking that for the incremental cost of 2 x IC to put in a 7.1.4 anyway as doing it later would be harder...... but would this layout even work given the lack of distance at the back (and if so what would it look like)? At the rear IC just above the Rear Surrounds?

Go 7.1.4 - more is better!
Seriously though, I am far from a tech expert on this, but as an analogy, I have a small HT room and had a few comments when building that 5.1 would be enough for my space. But similar to your thinking, it'd be harder to go back and add 2 channels than just put them in up front. So, since I had the walls open and money set aside anyway, I went ahead with 7.1. and I will say it has helped me with the upgradeitis itch. Never say never though!

Cheers,

Tossing my 2c in, I wonder if there would be enough separation between the ceiling and surround speakers, given the height the surrounds will be at? I use both Auro-3D and Atmos, and I think they would both be effected quite a bit.
Also, angling in (2) M3s from the rear corners for a 5.x.4 setup might work out better for the room shape and seating, and you wouldn't need the extra amp.
I've found I prefer QS8s over M3s for surround, even though counter to specs.

Edit: Final thought, if you used on-wall M3s you might be able to mount them flush in the rear corners, closer to head level. Since they have downward facing ports, that wouldn't interfere. Not only would you be following the Atmos angles for surrounds, you would also have good separation between your surround and height layers. 5.x.2 with zone 2 maybe?

Looking forward to seeing how you work it out.

Yeah, I agree with Steve and as I stated before, that separation is important, which is why I placed the speakers in his layout where I did.

That said, putting the surrounds in the rear corners puts them in the same plane as the rear overheads. That just won't work well. Nice idea though from a "where can I stash these speakers" perspective.

Keep in mind that any immersive setup still relies heavily on a solid base 5.1 or 7.1 setup. In a 5.1 setup, the surrounds are on the sides, not the rear, and while the seating area is pretty far to the back, you really don't want the surrounds in a 5.1 setup (which should be the base that you build off of, or a 7.1 if going that route) behind the listening area. Most 5.1 soundtracks are created to just go to the side of the listener, and not behind them. That is where 7.1 comes in. Sound mixers wanted to take the surround experience even further by giving sound behind the listener, without losing the long standing side surround sound.

In my diagram above, the side surrounds are actually in front of the standard Dolby spec as well, but this has been experimented with countless times over at AVS for years now - having side surrounds in front of the listening area when there are either rear surrounds (like in a 7.1 setup) or other speakers further back, like the overhead Atmos speakers, and people have raved about it. It also allows for greater separation between all of those speakers, filling in the audio "gaps" in the room more, and letting the receiver/processor handle the sound placement.

Again, my diagram edits were based off of using only native Atmos/DTS:X content or one of their upmixers.

None of it is ideal, but that is the space that we are working with, and it will still be a great experience.

I still stand by my "monopole only" stance (I went from four QS8s for surround duty to four on-wall M3s when moving to Atmos and love it), but like Steve indicated, he loves it with his QS8s and "to spec or not" you really will have a great sounding room with speakers filling those gaps, and I am certainly not going to fault someone for liking quadpole speakers (about as far away from spec as you can get, LOL) in an Atmos setup if they like it.

Your room isn't as great as a purpose built space for audio, but your room also serves multiple purposes, and will have a cozy feel to it even when not watching movies.

So now you have even more to think about. Steve brings some new thoughts for you to the table.

Lots to think of.

I'll mull all of this over as I wait to get the plans back from the builder/designer as the front three speakers will need to be customized to fit the space.....

I'm leaning towards putting in a 7.1.4 physical layout and then hearing what is "best" in this space with either a 7.1.2 or a 5.1.4 driven (or adding a 2ch amp for full 7.1.4). Also due to the sloping roof, the rear IC will be 2m higher than the Rear Speakers (that will also be angled down to the seated posn) - so I should get some separation???).

Thanks for all the feedback!

My vote 7.1.2

The sloped ceiling with a sharp apex at the rear of your room is going to cause problems if you place ceiling speakers nearby. You are going to get a pronounced "cupped hands" effect on your response in those channels with an after ring. The energy arriving at the listening positions will be almost all reflected energy off the rear wall. Not ideal for a discrete object mix.

Nick's 7.1.2 diagram layout is near ideal. The location of wall mounted M3s for rear surrounds will cause hot spotting near listeners. I recommend widening their positions slightly and aiming them at the main listening position.

Sounds like you are accounting for your ceiling slope when positioning your ceiling height channels.

The 2nd order bass width null will be shifted towards your sliding door wall by a couple of feet. You will have a hole at 39hz in the mlp if you put your subs on the left wall with wildly varying response over the listening area. They should go under each window on the front wall with the left sub output lowered to compensate for boundary gain.

So, predictions for rear height channels: I stole this image from online (sound and vision) and edited it to illustrate what I think the trend on the response will be. This is the best case scenario for ceiling mounted rear height speakers. Likely you can add pitched ring too.



This is all based off some quick napkin math and acoustical theory. In the spaces I have been involved with the math usually follows trends in real (rectangular) rooms though.

What do the "openings" in your room open to? This will affect your room decay times and low frequency behavior to a huge degree. I hope you have a good designer. The rear ceiling corner is an issue. (The issues I brought up are obvious and an HT designer should spot these right off.)

** Note that I too was somewhat reluctant to put the rear surrounds so close to the seating area in his diagram, but that is where they should be for separation (plus horizontal location in an ideal world) and he said that they would be mounted high on the wall, pointing down, adding to the distance and dispersion of sound which *should* mean less hot spotting.

That was my thoughts on it anyway. But yes, generally having a speaker right next to, or behind your head will not be so good.

Why so high back there? Didn't catch that. Ah I see, to match the sliding door speaker height all around. Makes sense now.

Sorry my brain always turns into an audio lawyer now. If\then risk\reward kinda mentality. lol. I admit I got caught up in the nice diagrams and went from there.

No harm, no foul.