Hopefully we’ll get a definitive answer to what happens when users playback Atmos and TrueHD 7.1 mixes on non Atmos/7.1 surround systems (typically 5.1, maybe some Quad only system users too).
I have a set of Dolby Atmos channel identification test files with encoding for: 5.1.2, 5.1.4, 7.1.2, 7.1.4 and 9.1.4. I also have a TrueHD 7.1 channel identification file.
I have two surround systems. One is 7.1.4 and the other 5.1. Both systems have Denon AVRs with Atmos decoders. I can play all the test files via HDMI Passthrough sending the raw Atmos/TrueHD bitstream to the AVRs for decoding.
The Tests:
Playback each file on my 5.1 system and listen to each channel. Can I hear all the channels in each test file?
Here are the Dolby Atmos Channel Test files from an official Dolby Atmos Demo Disc. Each file contains a 10 sec discrete signal to each channel in turn:
https://drive.google.com/drive/folders/1Dv8rQ00Ur_6tVb1iXc1iZPCYMiT96gRp?usp=sharing
DISCLAIMER: Fair use is claimed on all test files, as their purpose is only for the promotion of Dolby Atmos music, testing and technical evaluation for our members. QuadraphonicQuad is a non-profit, non-sponsored website.
The Results:
TrueHD 7.1: Yes. All channels can be heard. The rear channels are heard in the side surround speakers. Conclusion: If you have a TrueHD decoder all channels are mixed into the 5.1 output, surrounds are blended.
Atmos 7.1.2: Yes. All channels can be heard. The rear channels are heard in the side surround speakers And the ceilings are mixed into my side surround speakers. Conclusion: If you have an Atmos decoder all channels are mixed into the 5.1 output, surrounds are blended along with top/ceilings.
Need test results for a user with an old TrueHD decoder (and no Atmos decoder) to test what happens to the two ceiling channels (I’d think the Atmos ceilings will be ignored but you’ll get the 7.1 bed channels as per TrueHD test above)
Atmos 7.1.4: Yes. All channels can be heard. The rear channels are heard in the side surround speakers, rear ceilings in side speakers and front ceiling channels into front L/R speakers. Conclusion: If you have an Atmos decoder all channels are mixed into the 5.1 output, surrounds are blended along with top/ceilings.
Need test results for a user with an old TrueHD decoder (and no Atmos decoder) to test what happens to the four ceiling channels (I’d think the Atmos ceilings will be ignored but you’ll get the 7.1 bed channels as per TrueHD test above)
NOTE: These results should be consistent with playing back Atmos and TrueHD 7.1 from blu-ray discs since the test decoding was done on an AVR (and would be same on a BD player with bit streaming or if the BD player is used to decode to PCM)
EDIT: This post later in this thread summarises how Atmos mixes get played on nome Atmos systems:
https://www.quadraphonicquad.com/fo...sults-questions-experiences.29057/post-516125
I have a set of Dolby Atmos channel identification test files with encoding for: 5.1.2, 5.1.4, 7.1.2, 7.1.4 and 9.1.4. I also have a TrueHD 7.1 channel identification file.
I have two surround systems. One is 7.1.4 and the other 5.1. Both systems have Denon AVRs with Atmos decoders. I can play all the test files via HDMI Passthrough sending the raw Atmos/TrueHD bitstream to the AVRs for decoding.
The Tests:
Playback each file on my 5.1 system and listen to each channel. Can I hear all the channels in each test file?
Here are the Dolby Atmos Channel Test files from an official Dolby Atmos Demo Disc. Each file contains a 10 sec discrete signal to each channel in turn:
https://drive.google.com/drive/folders/1Dv8rQ00Ur_6tVb1iXc1iZPCYMiT96gRp?usp=sharing
DISCLAIMER: Fair use is claimed on all test files, as their purpose is only for the promotion of Dolby Atmos music, testing and technical evaluation for our members. QuadraphonicQuad is a non-profit, non-sponsored website.
The Results:
TrueHD 7.1: Yes. All channels can be heard. The rear channels are heard in the side surround speakers. Conclusion: If you have a TrueHD decoder all channels are mixed into the 5.1 output, surrounds are blended.
Atmos 7.1.2: Yes. All channels can be heard. The rear channels are heard in the side surround speakers And the ceilings are mixed into my side surround speakers. Conclusion: If you have an Atmos decoder all channels are mixed into the 5.1 output, surrounds are blended along with top/ceilings.
Need test results for a user with an old TrueHD decoder (and no Atmos decoder) to test what happens to the two ceiling channels (I’d think the Atmos ceilings will be ignored but you’ll get the 7.1 bed channels as per TrueHD test above)
Atmos 7.1.4: Yes. All channels can be heard. The rear channels are heard in the side surround speakers, rear ceilings in side speakers and front ceiling channels into front L/R speakers. Conclusion: If you have an Atmos decoder all channels are mixed into the 5.1 output, surrounds are blended along with top/ceilings.
Need test results for a user with an old TrueHD decoder (and no Atmos decoder) to test what happens to the four ceiling channels (I’d think the Atmos ceilings will be ignored but you’ll get the 7.1 bed channels as per TrueHD test above)
NOTE: These results should be consistent with playing back Atmos and TrueHD 7.1 from blu-ray discs since the test decoding was done on an AVR (and would be same on a BD player with bit streaming or if the BD player is used to decode to PCM)
EDIT: This post later in this thread summarises how Atmos mixes get played on nome Atmos systems:
https://www.quadraphonicquad.com/fo...sults-questions-experiences.29057/post-516125
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