Dolby Atmos beyond 7.1.4 - Part 1 (2023) (2023)

A little over a year ago, I began experimenting with ways to expand my Dolby Atmos surround sound system beyond the 7.1.4 limitations of current consumer hardware. My constant search for the best possible Atmos experience in my home recently led me to make a further upgrade. Today my home theater system is so complex that I actually have to run three A/V receivers at the same time to drive all my speakers.

In most home theaters, 7.1.4 channel sound should suffice. While the Atmos format (and its rival DTS:X) can support additional speakers, there hasn't been much demand from consumers and there hasn't been much pressure from manufacturers to do so. There are currently only high-end boutique deals, say for $37,000Trinov height 32Decode more than 11 channels simultaneously.

Still, for some of us, being limited to four vertical channels wasn't enough to fill the top of the room with sound. My own home theater is one long room with plenty of space behind my seats. Combined with the low ceiling and only four speakers (two at the front of the room and two at the back), it was hard to convincingly visualize the sound from above. This problem was compounded by the fact that when I built my home theater system (before I even thought about surround audio), the speaker placement was far from ideal for Atmos. The speakers are now supported by wall and ceiling wiring and I can't move them without rearranging the room. That is not an option at all.

A better solution would be to install an additional loudspeaker halfway between the other longitudinal channels (upper middle position). Unfortunately, the asking price of the Trinnov processor is way beyond my budget. I need to find a way to improvise similar effects at a fraction of the cost.

first attempt

II wrote an article last year.He explains how I put together a complex system (jokingly called "Zatmos") to get extra channels on my ceiling with a second A/V receiver. I recommend reading this article to get a basic idea of ​​how this is possible.

Even then, I wasn't the only one who experimented with it and knew that my Zatmos system wasn't as ideal as I'd hoped.in the AVS forum, a member named Scott Simonian went even further and fully usedThree A/V receiversConsequently, the 7.1.6 setup (affectionately named "Scatmos") was created to better fit the intent of the original Dolby Atmos mixer.

For a while I decided not to go that far. The complexity of installing, wiring and configuring three A/V receivers seems excessive to me. I feel the results I get with Zatmos are good enough for most tasks, and I take a degree of selfish pride in finding a way to do this with just one additional receiver instead of two.

However, in recent months, my attitude has changed and I am increasingly dissatisfied with the Zatmos setup. Ultimately, he knew that if he wanted to do it, he had to do it right.

all go out

The silly nicknames Zatmos and Scatmos could be more formally summarized under the heading "Dolby Atmos Extended". I want to clarify here that I did not develop the Scatmos process. Thanks to Scott Simonian and others at AVSForum for helping you with this issue. With your permission, I just wanted to explain it here.

One of the advantages of these experiments is that they are relatively inexpensive to assemble, although their installation can be quite complex. While your primary A/V receiver should be a Dolby Atmos (or DTS:X) model capable of decoding 7.1.4-channel audio from a Blu-ray or UHD surround audio track, your secondary receiver doesn't need as much I'd like to think Any receiver with at least Dolby ProLogic II processing will do. (If you're using multiple add-on receivers, I recommend making them identical to each other.)

While checking the for-sale ads on my local Craigslist, I was patient and picked up a pair of used Marantz SR4400s for less than $100 each. This is a low-cost basic (or almost basic) Dolby Digital/DTS model from 2003. It's so simple, there isn't even an on-screen menu system. For configuration, I just have to use the front panel display. The receiver does not have HDMI and cannot, but does not have to, process lossless Dolby TrueHD or DTS-HD Master Audio signals. All you need is a pair of stereo analog inputs (all receivers have them) and ProLogic II.

The simple act of finding a place in my system for another A/V receiver turned out to be much more difficult than I would have liked. Because I didn't have enough rack space for my main equipment, I had to remove all the components, take the shelves apart, rearrange the tiers, reattach and connect most of the equipment. I then had to do the same for the second shelf to add a layer. My Blu-ray and HD DVD players used to be on the main shelf and have now been moved to a second shelf so I can keep all my audio equipment and speaker cables together to reach. That alone is a great pain.

Having done that, this is the basic idea of ​​Scatmos: you want to install six ceiling speakers: front, center and rear ceiling. (The following sketches do not represent my personal speaker design, but I did it to show what it would look likeoughtEnd. ) Your main A/V receiver will be set to decode your maximum of 7.1.4 channels configured as Top Front and Top Rear.

All four height channels should be routed to the analog preamp connections on the main AVR. You should not connect speaker wire to these channels on the main AVR. For all height channels, the speaker cables connect to the auxiliary AVR only.

The pre-outs of the Top Front Left and Top Rear Left channels go to the left and right stereo inputs of the AVR 2.

The front outputs for the top right front and top right rear channels go to the left and right stereo inputs (unlike the AVR 2) of the AVR 3.

If that sounds confusing, it can be really intimidating trying to organize the actual routing of wires and cables. I highly recommend drawing a diagram showing where to put it.

To function properly, each downstream sub AVR must receive a stereo signal consisting of a front and rear, and use any mono data common to both to matrix the center channel between them (similar to a ProLogic II). The center channel is pulled for dialogue (usually between the left and right speakers at the front of the room). So you get six channels of elevation information from the original four.

This is the theory reduced to its most basic elements. It's actually a bit more difficult to get it to work once the connection is established, which I'll cover in Part 2.

Read Part 2