understanding lossless 7.1 and their core

[daaceking]

Hello

Dolby and DTS both use lossless audio on blu-ray and regularly use 7.1 channels. They both also use a 5.1 core. My question is, is there any difference in sound, by which i don't mean a lossless to lossy comparison. Nor do i mean difference in sound channels. I mean are there sounds that exist in 7.1 that don't exist in the core. Such as music, sound effects etc

Thanks

[Deleted User 11865]

The extra channels get downmixed into the core, just like the center and surround channels get downmixed into left & right when doing a Stereo downmix. Otherwise, since in most surround tracks, voices are found in the center channel, nobody would hear any voices when listening on any Stereo sound system! A bit inconvenient maybe?

[daaceking]

Ah, i see! So modern hardware must
Upmix to lossless 7.1 then, because legacy equipment can't read the special data right?

[Deleted User 11865]

Don't quite understand what you mean here, sorry.

[daaceking]

well, you said that the core basically has no sounds/music missing from the 7.1 lossless track.

older hardware [which is incapable of playing lossless audio] will play the core because that's why it exists [for compatibility]. so then to create a 7.1 system it uses the core & the "residual?" to create the 7.1 lossless track. so the only way it can do that is by upmixing. right?

[Deleted User 11865]

In the case of DTS-HD, the decoder:

- decodes the DTS core

- decodes the HD extension

- adds up both signals (for more detail, please read the DTS specification)

In the case of TrueHD, the core Dolby Digital track is interleaved with the TrueHD track, but they're otherwise fully independent. The decoder decodes one substream and discards the other, depending on what it supports.

Upmixing, on the other hand, would be taking a signal with fewer channels than the sound system it's going to be played on (for example, playing a 5.1 stream on a 7.1 system, sometimes the surround/side channels will be repeated in the rear channels, or sometimes there may be some additional processing involved).

[daaceking]

so with with the incorrect terminology excused and my layman terms, it's the same thing

basically it's my original question where i'm asking if an old reciever that doesn't support dts-hd or truehd, or even if we're talking about libdca, whether every musical note and everysound effect still exists that would exist in the lossless audio whether it be the dts+hd extension or the parts which is ultimately truehd.

[Deleted User 13735]

Your hardware must be capable of decoding 7.1 in whatever digital flavor you feed it.
Format support in receivers varies greatly. If it's not stated on the front of the receiver, it likely doesn't support it.
It's that simple.