Tommy SACD vs. DVD-A

[Xenu]

Hey all,

So someone finally posted a demultiplexed version (albeit downconverted to 16/44.1) of Tommy at Demonoid.

I recall that a while back, Luke posted a "center-channel+LFE" version of "The Acid Queen" ripped from the SACD. Unless I'm misremembering, the vocal track there was completely dry. On this DVD-A rip, however, the center vocal track has a peculiar digital effect applied to it.

Can anybody check to see whether this difference is in fact real? I don't think that the vocal effect is just something added by the bootlegger, as it shows up again on the vocal on "Smash the Mirror."

[lukpac]

http://lukpac.org/mp3/samples/sympathy-acid.mp3

(with some Sympathy for the Devil too)

As I said, I will try ripping the DVD-V portion and seeing what I come up with.

[Xenu]

http://lukpac.org/~handmade/acidforluke.mp3

Meanwhile, that's an MP3 of what purports to be the center (vocals-only) track from the DVD-A. The differences should be pretty evident.

[krabapple]

I have both discs but won't be set up to listen to them again until this weekend.

[lukpac]

I just ripped the DVD-V tracks. Not only does the center track have echo, but the LFE track is *nothing* like on the SACD.

This is shaping up to be quite strange.

Let me re-dub the SACD and I'll post some clips.

[Xenu]

I find this fascinating. So there're endless amounts of people who claim to hear subtle differences in bass and treble response between the SACD and DVD-A, yet nobody ever noticed that the actual audio content differed? Bah.

[krabapple]

LFE on DVD-V should be 10 dB lower than on SACD when comparing 'ripped' DVD-V to analog output SACD; down the line (i.e in the AAVR or in the player if the player is doing the decoding) the DVD-D LFE is 'expecting' a 10 dB boost -- this is Dolby Digital spec, and usually followed by DTS mixes too. It also appears to be the case for DVD-Audio (but not SACD). However, some multi-format SACD players apparently lower the LFE internally by 10dB, then carry on the rest of their processing as normal, meaning that somewhere down the line the LFE has to get a 10dB boost, as with DD and DVD-A. See the first post in this thread for a more thorough discussion of LFE differences:

http://www.avsforum.com/avs-vb/showthre ... 147&page=1

Dolby Digial center channel also gets Dialnorm adjustment in DD-certified players/AVRs, making it likely different at output compared to other formats.

So as you can guess, comparing DD to DTS to DVD-A to SACD, even with the same mix, is not straightforward.

[lukpac]

I'm not talking about a 10 dB difference. The LFE on the SACD (as I posted above) is practically full range. On the other hand, the LFE on the DVD-V could barely be heard through my computer speakers, since it was only comprised of very low frequency information.

My Mac was having issues last night, so I couldn't post clips. I'll try tonight.

[krabapple]

I'm not talking about a 10 dB difference. The LFE on the SACD (as I posted above) is practically full range. On the other hand, the LFE on the DVD-V could barely be heard through my computer speakers, since it was only comprised of very low frequency information.

Yes, that's another difference between Dolby Digital and SACD. DD LFE is restricted to 150 Hz, SACD LFE can be full-range (but really, it shouldn't be -- there's no reason to put high frequencies in LFE, unless that channel is used for some other purpose -- such as as a 'height' channel).

[lukpac]

Yes, that's another difference between Dolby Digital and SACD. DD LFE is restricted to 150 Hz, SACD LFE can be full-range (but really, it shouldn't be -- there's no reason to put high frequencies in LFE, unless that channel is used for some other purpose -- such as as a 'height' channel).

Ah, so you can't put higher frequencies in DD LFE even if you try? I have to wonder what the DVD-A portion sounds like.

Doesn't explain the echo on the vocal, though.

Hopefully I can post some clips later tonight.

[lukpac]

Ok, finally figured out a workaround to boot my Mac.

Rip of the DVD-V/DD track, center (left) and LFE (right):

http://lukpac.org/mp3/who/aq-dd.mp3

Dub of the SACD, same:

http://lukpac.org/mp3/who/aq-sacd.mp3

For anyone interested, the SACD was played in "MCH Direct" mode on my SCD-CE775.

[Xenu]

The LFE channel on the DVD-A seems to include a decent chunk of high-end information.

[Xenu]

So they are definitely different. Fancy that. Luke, does Roger's voice have a similar, if slightly less pronounced, effect on the SACD of "Smash the Mirror?" (center channel, although his voice isn't isolated at all)

[lukpac]

So they are definitely different. Fancy that. Luke, does Roger's voice have a similar, if slightly less pronounced, effect on the SACD of "Smash the Mirror?" (center channel, although his voice isn't isolated at all)

I'll have to check.

And what do you mean about the LFE on the DVD? Do you mean my clip? Or the actual DVD-A content?

[Xenu]

The DVD-A rip I have has a lot of treble info in the LFE channel. I have no idea if variable settings produced this.

http://download.yousendit.com/B9DE29C048464525

The first part is the center channel of "Smash the Mirror;" the second is the LFE channel of "Sensation."