'Dolby surround' V 'Dolby surround 2' downmix differences?

[datauser]

I get a little mystified by these two choices/switches when using Azid. Which is better? I always downmix to Dolby Surround 2 for my mp3 2.0 channel files, but I read prologic signals give awful warbling of the rear channels in reproduction using mp3?

Assuming Dolby surround 2 is prologic down mixing? Azid also gives a straight Dolby surround option too, which is I assume older technology of the above. Any audio guru please explain the benefits of these or deficiencies if any, and greatly appreciated. Finally can you get away with 112kbp/s mp3 downmixed to Dolby surround 2 from a 5.1 source or should final bitrate be much higher to preserve signals? :thanks:

[tebasuna51]

Azid can downmix to:

- mono, to play with mono amplifier
- stereo, to play with stereo amplifier
- dpl, to play with amplifier/receiver with dpl decoder and 4 channels Left, Right, Center and Surround
- dpl II, to play with amplifier/receiver with dpl II decoder and 5 channels Left, Right, Center, Surround Left and Surround Right

Each one is the best for each player.

112 Kb/s mp3 is only good for mono.

[hello_hello]

Finally can you get away with 112kbp/s mp3 downmixed to Dolby surround 2 from a 5.1 source or should final bitrate be much higher to preserve signals? :thanks:

The original poster in this thread seems to think 160kb/s is the minimum for maintaining a reasonable amount of the surround info, but personally if I was mixing down to Dolby surround I'd be running comparison encodes for myself.
http://forum.doom9.org/showthread.php?t=162546

[datauser]

The original poster in this thread seems to think 160kb/s is the minimum for maintaining a reasonable amount of the surround info, but personally if I was mixing down to Dolby surround I'd be running comparison encodes for myself.
http://forum.doom9.org/showthread.php?t=162546

Being the original poster:D I would not be too sure there about 160kbps being the absolute minimum for keeping most of the sound track info intact, but the general consensus is that it sure is a good starting point.

My own tests to ascertain this, this afternoon using a prologic II TV show to me joint stereo is superior than stereo for preserving surround(downmixed to dpl II) replication at 160kb/s and below. Ordinary Stereo(downmix to either dpl or dpl II) produced a washy(can't describe the sound really: ssshh) in some effects coming from the rear channels at lower bitrates. 160 is not the minimum to preserve good surround signals, but it certainly appears to preserve a punchier/crisper sound track a whole lot better than lower bitrates e.g bird songs sounded surprisingly much more naturally encompassing 3D, especially if mixed using joint stereo to dpl II. Regular Stereo not so good and seemed more 2D, a bit flat in playback with 160kbp/s and more so with lower bitrates mixed to dpl or dpl II! Joint stereo never exhibited these artifacts for want of a better word.

[tebasuna51]

- Don't mistake mono, stereo, dpl, dpl II decode downmix with join stereo mp3 encode option. Isn't related.

- Low bitrate affect very much to high frequencies (ssshh, birds) for stereo o dpl II downmix.

- Use stereo mix to play with stereo speakers, or dpl II to play with a receiver with dpl II decoder and 5.1 speakers.

I don't know what answer you can need more than this.

[datauser]

Subjective tests for me show j/s is far superior to stereo(mixed to dpl or dlp II) and is related for quality playback. Thanks for help, we will leave it at that.