Laserdisc digital audio question

Hi folks. I'm embarking on some laserdisc audio rips for various movies in an attempt to recover some otherwise-unreleased theatrical mixes. The first of these is Star Trek II: The Wrath of Khan, and I've encountered a curious issue - perhaps someone more familiar with laserdisc in general can advise?

The sound captures fine at 44.1/16-bit via optical in on my Creative soundcard (not bit-perfect, but what you gonna do). It's a strong-sounding track, far more impressive than the timid 7.1 on the Blu-ray.

However, the overall level on side B appears to be lower than that of side A. It's not a dramatic difference, but at no point on the capture from the second side does the waveform reach the same peaks as the 'big moments' on side A: Khan's initial attack on the Enterprise, then Kirk's retaliation. I'd really expect the Mutara Nebula battle and the Genesis explosion to hit similar highs, but nope.

So I guess the question is - it it common (or even heard of) for the digital tracks on sides A and B of a laserdisc to be mastered at different levels? Or is this just a strange quirk of this mix, that it gets quieter as the film goes on? Any thoughts would be appreciated...

Thanks for the response. This is the 1991 US NTSC disc - I got a nice sealed copy.

I've done another capture with the same set-up (Back to the Future) and the levels are all a-ok - I suspect it's the disc. No problem, I'll give side B a 1db (or so) boost and that should even things out.

I wish I could offer some help, Jonno.  I'm very interested in this.  I have this LD, but I hadn't noticed that the audio was better than that on the BD, so I'll have another listen.

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You're planning to sync the audio to the BD, are you?

Yes, that's the same disc. I'd be interesting to know if you find side 2 to be a tad quieter than side 1.

The BD syncing is already done - I was just pondering this level issue before setting it in stone. I'm happy to share the result when it's done if you'd like a listen.

Yes, please.  Thanks.  I'll also listen to the disc, but if it's only a matter of 1db or so my ears probably won't be good enough to notice.

I'll have to work out how to capture/rip LD audio one day.  My player has an optical out, but I believe I'm right in thinking that AC-3 is output only through the RF out and that the optical out is for PCM or DTS.

I, too, would be interested in getting this.  I have the same LD version and I usually use the multichannel stereo setting on my receiver when listening to the audio on this movie.

Cheers for the work.

:)

I'm just uploading the mix now - when it's done I'll PM you chaps the links. If anyone else is interested let me know.

I'm finding myself doing a fair few of these at the moment - my tolerance for 5.1 remixes is getting thinner as I get older. I'll start a thread at some point to keep track of the ones I've done - the next will be a capture of the 35mm Alien mix (from the CAV special edition) to go with Msycamore's 70mm mix (from the THX laserdisc).

I am of course limited to digital PCM tracks here - I don't really have the resources nor inclination to go down the 5.1 AC-3 route, since they're often remixes and there are other folks on these boards who are already doing fine work on the important ones.

Jonno said: my tolerance for 5.1 remixes is getting thinner as I get older.

Tell me about it!

I am of course limited to digital PCM tracks here - I don't really have the resources nor inclination to go down the 5.1 AC-3 route, since they're often remixes and there are other folks on these boards who are already doing fine work on the important ones.

But you did decode the AC-3 2.0 track on the Star Trek II disc to get the PCM, didn't you?  As far as I know, there is no PCM on it.

I feel quite the dilettante trying to educate someone on this when I've learnt this stuff so recently myself, but...

Most (all?) laserdiscs have analogue audio (hopefully with CX encoding) - you just use the L/R phono out to capture this.

More recent discs (mid 80s onwards) have digital PCM as well (aka digital SOUND) - with support for up to 2 channels - which you can capture via the optical output with a suitable soundcard. This is my typical method, Star Trek II no exception.

Top-notch discs include a modulated AC-3 stream (which can accommodate, and may always consist of, 5.1 channels). You need an RF decoder just to hear this. I do not own one.

DTS I know less about, though I believe it comes in a packaged bitstream which you can decode direct from the optical (as you would with a DVD).

I'm sure someone far more knowledgeable will correct me on part (or all) of this - it's been a steep learning curve since I've ignored laserdiscs entirely until the last two months. The lure of all these original soundmixes proved impossible to resist...

Ah, okay.  So when it says digital sound (on the Laserdisc Database) with the boxes with a circle in one and and a cross in the other, it means PCM.  I didn't realize that because I thought that icon went with the Dolby icon next to it.  I basically knew everything else, but thanks for clearing that up. :-)

Thank you both.  I'm embarrassed that I didn't recognize the letters CX.

Jonno's PCM track for Star Trek II is excellent. :-)

I'd like to - while I don't hold it in the same esteem as Khan, I do like the Motion Picture a lot. It's had an interesting release pattern, what with all the director's edition business and all, but a strong theatrical release could be made from the current Blu-ray together with the digital stereo from the 1991 laserdisc: http://www.lddb.com/laserdisc/11219/LV8858-2WS/Star-Trek-I:-The-Motion-Picture-%281979%29

While I have the Blu, I don't have that laser. Let me investigate further...

Jonno said:

I'd like to - while I don't hold it in the same esteem as Khan, I do like the Motion Picture a lot. It's had an interesting release pattern, what with all the director's edition business and all, but a strong theatrical release could be made from the current Blu-ray together with the digital stereo from the 1991 laserdisc: http://www.lddb.com/laserdisc/11219/LV8858-2WS/Star-Trek-I:-The-Motion-Picture-%281979%29

While I have the Blu, I don't have that laser. Let me investigate further...

Maybe there is a Star Trek analog audio project that needs to happen.  Outside of the original crew movies I have Generations, First Contact, and Insurrection on LD.  I believe the release you linked to was part of the 25th anniversary set which I have.

http://www.lddb.com/laserdisc/21947/LV12954-7WS/Star-Trek:-The-Movies-25th-Anniversary-Collection

I also have this version of ST IV ...

http://www.lddb.com/laserdisc/19613/LV12883-2WS/Star-Trek-IV:-The-Voyage-Home-%281986%29

I'm very excited about the possibility of having this audio for everyone to enjoy.  I also have DTS theater audio for Generations, First Contact, Insurrection, and Nemesis as well. 

I can't wait to see where this all goes.

These are the other Star Trek LD's I have .....

Generations

http://www.lddb.com/laserdisc/11213/LV-32988-2WS/Star-Trek-VII:-Generations-%281994%29

First Contact

http://www.lddb.com/laserdisc/11212/LV332433-WS/Star-Trek-VIII:-First-Contact-%281996%29

Insurrection

http://www.lddb.com/laserdisc/19611/LV-335883WS/Star-Trek:-Insurrection-%281998%29

Ok folks, I just did The Motion Picture theatrical. It was well worth the effort, actually - it's a really interesting mix, albeit quite rough at times (Robert Wise was quite adamant that it be properly 'finished' when he did his later director's edition).

The Dolby TrueHD 7.1 on the Blu-ray is, in comparison, fairly faithful in content; however it includes a great deal of forced panning to (presumably) 'liven up' the soundfield. This 1991 laserdisc track sounds just as it would have on a 35mm print, rough edges and all... and yes, the music sounds great.

PM me for links.