Atmos & DTSX without Ceiling Speakers

[Gary Cook]

As per bootman's suggestion;

Nov 12, 2017 19:48:43 GMT -5 bootman said:

Nov 12, 2017 19:22:42 GMT -5 Gary Cook said:

...even in 5.1 Atmos sounded better than the same movies, using the same hardware obviously, via Dolby TrueHD and DTS-HD.
As a result, even if I was not adding the 2 ceiling speakers to my existing 5.1 system, I would still be looking at implementing Atmos/DTSX and Auro.

Interesting observation worthy of a separate thread.

A bit of background, about 12 months ago I helped a long time friend of mine install a pair of ceiling speakers to take his system to 5.1.2 suitable for Atmos and DTSX and more recently Auro. He has an inexpensive Onkyo AVR using external power amplifiers, FWIW none of his gear is Emotiva (I haven't been able to convert him .....yet). He had the Atmos receiver for quite a few months before he got around to organising the ceiling speakers for us to install.

Just for fun, in that period, we tried a few experiments, one of which was to see if Atmos sounded better using just the 5.1 speakers than the other (non object oriented) formats. We had a number of test BD's, the Dolby Atmos demo Rain Storm being one of them. First time we tried it we just used the 5.1 connections and flicked between formats. Whilst the Atmos 5.1.2 tracks sounded better, clearer, cleaner more distinct there was stuff missing that we could hear with Dolby True HD. Of course, obviously no ceiling speakers, so what was supposed to be coming out of the .2 wasn't because they weren't there.

We are both a bit impatient, so the next time we tried it we used a couple of RCA splitters (in reverse) to join the 2 side channel outputs (from the AVR) to the ceiling speakers outputs and feed then into the power amplifier inputs for the side channels (ie; side inputs + ceiling inputs = side outputs). That solved the problem of the missing speakers, with what sounds were supposed to come out of the ceiling speakers now coming out of the side speakers added to what was supposed to come out the side speakers. This actually sounded pretty realistic, like the rain was blowing against the windows of the house instead of falling on the roof. So now not only did it sound better, but there was nothing missing. The big benefit was the ability to turn up the dialogue volume, which has a better effect than simply turning up the centre speaker volume.

While we were playing with the ceiling speaker positioning we did try locating them like rear speakers (in a 7.1 set up), just high up on the wall facing downwards at a 45 degree angle. That sounded more realistic (like rain on the roof) than combining with the side speakers. But in the end we went for the ceiling location, albeit in a front and rear orientation (Dolby suggests side by side) because his room is longer than it is wider.

The moral of the story, just because someone can't or doesn't want to fit ceiling speakers they shouldn't dismiss Atmos/DTSX, there are other worthwhile benefits.


Cheers
Gary

[bootman]

So playing Atmos material on a 5.1 system still causes audio content to be lost?
No down mixing is happening?

[KeithL]

Not exactly.

The full surround mix is NOT simply decoded - then mixed down into the channels you have.
The surround sound mix actually contains specific versions of the mix for different modes.
So, when you play a 5.1 channel TrueHD disc in stereo, the disc is NOT simply decoded to 5.1, then mixed down to stereo.
The decoder extracts the two channel mix from the surround sound mix and plays it.

The same theory is true for Atmos.
If you play an Atmos disc on a 5.1 channel system, the decoder is going to extract and use the 5.1 channel version of the mix contained on the disc.
And, when that happens, nothing is going to be "dumped" or "thrown away".
HOWEVER, what is present in each mix, and in what proportions, is under the control of the producer.
(And so the two may be different - at their option.)
So, for example, they may decide that the rain sounds that are prominent overhead in the Atmos mix should be turned way down in the 5. 1 channel mix, or even deleted altogether.
(It makes perfect sense that the producer may decide that the sound that's presented loud overhead in Atmos may sound odd when coming from a head-level surround speaker at the same level.)

The way this would normally be phrased would be simply to state that an Atmos disc is BACKWARDS COMPATIBLE with Dolby TrueHD in 7.1 channels  or 5.1 channels, or even stereo.
Therefore, it will sound AS INTENDED when played on those systems (the sytem itself will not omit or discard any content).
(We generally assume that the producers intend the experience to be as similar as possible.)

Nov 13, 2017 8:36:10 GMT -5 bootman said:

So playing Atmos material on a 5.1 system still causes audio content to be lost?
No down mixing is happening?

[Gary Cook]

Nov 13, 2017 12:00:47 GMT -5 KeithL said:

Not exactly.

The full surround mix is NOT simply decoded - then mixed down into the channels you have.
The surround sound mix actually contains specific versions of the mix for different modes.
So, when you play a 5.1 channel TrueHD disc in stereo, the disc is NOT simply decoded to 5.1, then mixed down to stereo.
The decoder extracts the two channel mix from the surround sound mix and plays it.

The same theory is true for Atmos.
If you play an Atmos disc on a 5.1 channel system, the decoder is going to extract and use the 5.1 channel version of the mix contained on the disc.
And, when that happens, nothing is going to be "dumped" or "thrown away".
HOWEVER, what is present in each mix, and in what proportions, is under the control of the producer.
(And so the two may be different - at their option.)
So, for example, they may decide that the rain sounds that are prominent overhead in the Atmos mix should be turned way down in the 5. 1 channel mix, or even deleted altogether.
(It makes perfect sense that the producer may decide that the sound that's presented loud overhead in Atmos may sound odd when coming from a head-level surround speaker at the same level.)

The way this would normally be phrased would be simply to state that an Atmos disc is BACKWARDS COMPATIBLE with Dolby TrueHD in 7.1 channels  or 5.1 channels, or even stereo.
Therefore, it will sound AS INTENDED when played on those systems (the sytem itself will not omit or discard any content).
(We generally assume that the producers intend the experience to be as similar as possible.)

Just to clarify what we tried,spread over a few weeks.

First we told the AVR that it was a 5.1 set up so it used the Dolby True HD mix. That gave us a basis for what it sounded like (sans Atmos).

Then we told the AVR that there were ceiling speakers, ie; 5.1.2, even though there weren't any (the ceiling outputs from the AVR were plugged into an amplifier but there were no speakers connected), hence it used the Atmos mix. That gave us some idea of what was sent to the ceiling speakers that we couldn't hear ie; missing.

Then we used the splitters in reverse to combine the ceiling outputs from the AVR with the side outputs as inputs to the power amplifiers. That way the sound that was supposed to come out of the ceiling speakers actually came out of the side speakers (plus what was supposed to come out of the side speakers). We again told the AVR that there were ceiling speakers ie; 5.1.2, so it used the Atmos mix. That gave us an idea of what it sounded like having the "ceiling sounds" come out of the side speakers. Not all that bad actually.

Then we tried the ceiling speakers mounted like we would a pair of rear speakers, told the AVR that they were ceiling speakers hence 5.1.2 and it used the Atmos mix. That gave us an idea of what it sounded like having the "ceiling sounds" come out of rear speakers. Surprisingly good in fact.

Lastly when the ceiling speakers mounting kit finally arrived we mounted them in the ceiling (what a unique idea), told the AVR that it was 5.1.2 and of course it used the Atmos mix. The best sound so far, pretty impressive for a cheap and nasty AVR.

In every case, where the AVR used the Atmos mix, it sounded better, clearer, cleaner, more precise and had the big advantage of being able to adjust the dialogue volume. Whether that was due to the Atmos mixes being better or the AVR processing the Atmos mixes better I can't say. My conclusion was that it was worth upgrading to Atmos with or without ceiling speakers. Whereas there seems to be this universal belief that Atmos is only worthwhile if you want/can have ceiling speakers. Auro sounds good too and I can only assume that DTS-X will as well, a test for another day.


Cheers
Gary

[novisnick]

Nov 13, 2017 22:38:45 GMT -5 Gary Cook said:

Nov 13, 2017 12:00:47 GMT -5 KeithL said:

Not exactly.

The full surround mix is NOT simply decoded - then mixed down into the channels you have.
The surround sound mix actually contains specific versions of the mix for different modes.
So, when you play a 5.1 channel TrueHD disc in stereo, the disc is NOT simply decoded to 5.1, then mixed down to stereo.
The decoder extracts the two channel mix from the surround sound mix and plays it.

The same theory is true for Atmos.
If you play an Atmos disc on a 5.1 channel system, the decoder is going to extract and use the 5.1 channel version of the mix contained on the disc.
And, when that happens, nothing is going to be "dumped" or "thrown away".
HOWEVER, what is present in each mix, and in what proportions, is under the control of the producer.
(And so the two may be different - at their option.)
So, for example, they may decide that the rain sounds that are prominent overhead in the Atmos mix should be turned way down in the 5. 1 channel mix, or even deleted altogether.
(It makes perfect sense that the producer may decide that the sound that's presented loud overhead in Atmos may sound odd when coming from a head-level surround speaker at the same level.)

The way this would normally be phrased would be simply to state that an Atmos disc is BACKWARDS COMPATIBLE with Dolby TrueHD in 7.1 channels  or 5.1 channels, or even stereo.
Therefore, it will sound AS INTENDED when played on those systems (the sytem itself will not omit or discard any content).
(We generally assume that the producers intend the experience to be as similar as possible.)

Just to clarify what we tried,spread over a few weeks.

First we told the AVR that it was a 5.1 set up so it used the Dolby True HD mix. That gave us a basis for what it sounded like (sans Atmos).

Then we told the AVR that there were ceiling speakers, ie; 5.1.2, even though there weren't any (the ceiling outputs from the AVR were plugged into an amplifier but there were no speakers connected), hence it used the Atmos mix. That gave us some idea of what was sent to the ceiling speakers that we couldn't hear ie; missing.

Then we used the splitters in reverse to combine the ceiling outputs from the AVR with the side outputs as inputs to the power amplifiers. That way the sound that was supposed to come out of the ceiling speakers actually came out of the side speakers (plus what was supposed to come out of the side speakers). We again told the AVR that there were ceiling speakers ie; 5.1.2, so it used the Atmos mix. That gave us an idea of what it sounded like having the "ceiling sounds" come out of the side speakers. Not all that bad actually.

Then we tried the ceiling speakers mounted like we would a pair of rear speakers, told the AVR that they were ceiling speakers hence 5.1.2 and it used the Atmos mix. That gave us an idea of what it sounded like having the "ceiling sounds" come out of rear speakers. Surprisingly good in fact.

Lastly when the ceiling speakers mounting kit finally arrived we mounted them in the ceiling (what a unique idea), told the AVR that it was 5.1.2 and of course it used the Atmos mix. The best sound so far, pretty impressive for a cheap and nasty AVR.

In every case, where the AVR used the Atmos mix, it sounded better, clearer, cleaner, more precise and had the big advantage of being able to adjust the dialogue volume. Whether that was due to the Atmos mixes being better or the AVR processing the Atmos mixes better I can't say. My conclusion was that it was worth upgrading to Atmos with or without ceiling speakers. Whereas there seems to be this universal belief that Atmos is only worthwhile if you want/can have ceiling speakers. Auro sounds good too and I can only assume that DTS-X will as well, a test for another day.


Cheers
Gary

Thanks for the input!👍👍👍

[Erwin.BE]

Over on AVS in the hughe Atmos thread, a film sound mixer wrote once that more "aggressive" use of all the surround channels was used in Atmos soundtracks because it is aspected that more capable surround speakers are used in Atmos installs than typical HTIB with inferior surround speakers. Not sure how this translates to 5.1 mixes but the consensus was that the surround channels are used more than before.

[bootman]

Thanks for explaining how you reached your conclusion.
I have now reached mine and I have no further questions.

[405x5]

"Armos"....another competing format?

[Gary Cook]

Nov 15, 2017 21:43:31 GMT -5 405x5 said:

"Armos"....another competing format?

I have no idea what you are talking about ............



Cheers
Gary

[405x5]

Nov 16, 2017 1:06:05 GMT -5 Gary Cook said:

Nov 15, 2017 21:43:31 GMT -5 405x5 said:

"Armos"....another competing format?

I have no idea what you are talking about ............



Cheers
Gary

Hey!
You stole my fun...(that’s ok 👍

Bill