Well folks, it turns out the rumors of my doings are true: I have indeed produced a new version of the 70mm soundtrack, which can be found on the just-released 4K77 project.

Though the fundamental sound is still quite similar, this latest version represents a significant step forward in several ways. For a long time I put off revisiting this soundtrack as I felt the previous version was good enough that an update was not needed – unless I could make it a really major improvement that would justify the amount of work needed to redo it.

Everything in this third version is brand new, having been done over again essentially from scratch, all the way back to GOUT-synching the laserdisc audio and then building from there.

Improvements over the previous version include:

Increased audibility of midrange detail and reduction of high-end harshness due to global EQ adjustment.
Clipping and occasional clicks in the source laserdisc tracks have been repaired.
More seamless transitions between the 1993 base and the 1985 replacement material.
Elimination of phase issues during downmixing and bass management.
New, fully lossless LFE channel that no longer uses the special edition as a source.
Improved channel separation and sound field stability due to use of a Shure HTS-5300 for the upmix.

All of these are worthwhile improvements on their own, but together they add up to form a very nice update. The 1993 mixes all have a cut in the midrange at 2 kHz and a treble boost around 8 to 10 kHz. By reversing this EQ change, the tone of the mix becomes closer to how it was originally heard, and sounds smoother in the louder passages. Hiss and occasional crackling distortion are also reduced without needing to use noise reduction tools. The edits between sources are now seamless enough that I have a very hard time hearing that anything was even done to them in the first place, which is exactly how it should be. Use of iZotope’s Ozone and Insight plugins allowed for more precise matching of level and EQ than I had previously been able to achieve. Now, even the hiss does not change between edits.

The low end present in the 1993 mix has been removed from the center and surround channels and mixed solely into the left and right. This was done using a Linkwitz-Riley type crossover and preserves phase coherence between the channels. With a delay setting of 24 milliseconds on the surrounds, there is no longer a noticeable phase problem when this version is downmixed back down to stereo. Doing this is certainly listenable, if not stellar. I still recommend using a real stereo mix for 2-channel systems, whether it is the 35mm stereo mix or the non-upmixed version of this one. It just sounds better that way.

The LFE channel has been newly created by sending the front channels of the mix through a subharmonic synthesizer, the levels mixed in real time with a fader. Some manual editing was later done to prevent musical elements like timpani and bass drum from leaking into the LFE. The result is mostly similar to the previous version, but more tightly integrated with the main channels since it now has a closer harmonic relationship and the timing is locked in precisely. The goal was not to stand out, but to sound as if the new bass had been there all along. It is not possible to precisely replicate the boom channels of the real 70mm mix without adequate references, but it should be a close approximation given the material that is available. One bass effect, namely that of the Millennium Falcon struggling to escape the Death Star’s tractor beam, comes directly from the 1993 soundtrack; there are no longer any phase cancellation issues with this sound effect since it is now confined exclusively to the LFE channel.

The real draw here, of course, is the Shure HTS-5300 Acra Vector logic decoder used for the upmix. Having sought unsuccessfully to find one of these gems for some time, I finally located one on eBay earlier this year. Unfortunately, the seller wanted local pickup only, and since I was unable to travel to that area, it seemed I would have to let it pass me by. Thankfully, however, TServo2049 was able to obtain the 5300 locally and then mail it to me, and he has earned my everlasting gratitude for doing so, in addition to being credited in the 4K77 project for that reason. Indeed, I may well not have bothered with making a new version at all if it hadn’t been for this, so everybody give him a huge thanks for this invaluable contribution!

Since the Shure is an analog surround decoder, it necessitated sending the mix out into the analog domain and then recording its output back into digital again. Having been around plenty of audio engineers who routinely use analog gear in a digital environment, I’ve learned to embrace this hybrid method since the benefits more than offset any minor loss incurred by the extra conversion. The edited stereo track was played in Pro Tools through the line outs of a Universal Audio Apollo Twin and into the 5300, with the 5300’s output routed to an Audient ASP800 preamp, which handled the A/D conversion and sent the upmixed channels back into the Apollo through the ADAT connection, recording into the Pro Tools session as it played. Pro Tools’ initial output needed to be reduced in level due to the issue of sending a +4 dBu pro-level signal into -10 dBv consumer equipment, so the finished recording was then measured with Insight and its gain increased to get it back to its original level. Only the most minor of limiting was needed to prevent clipping in the center channel. A modest amount of noise reduction was used at the very beginning and end of the film since the Shure’s noise floor was noticeable there, and some de-crackling was needed on the surrounds; default settings in iZotope RX took care of this and produced no noticeable artifacts.

These changes were done at 32-bit float and then dithered back to 24-bit. The final result is 24-bit, 48 kHz and has been encoded to DTS-HD MA at this resolution. Both the 1080p and UHD versions of 4K77 contain this same file. I saw no need to make a 16-bit version since file size and bitrate were not an issue, but one could potentially be made if a smaller version was needed for another project. A 640 kb/s AC3 has been made, encoded from the 24-bit files.

The benefits of upmixing through the Shure are immediately apparent. When I heard what it sounded like for the first time, I was surprised at how different it was since I was so used to the sound of Prologic II. There is less crosstalk between channels and the sound field is more stable since the Shure detects panning and signal dominance along more vectors than any version of Prologic. Front channel sound effects do not get pulled to the rear as they sometimes are with PL2, nor is there any side wall imaging for the music. It comes across as being a fully front-oriented soundstage, with discrete-sounding surround effects making themselves known from time to time. The surrounds are monaural, as was the standard for Dolby Prologic decoders in the 80’s and 90’s, but Shure did Dolby one better by adding an “Acoustic Space Generator” to its surround output, which widens the mono signal through a custom comb filter designed to sound like it is being played through many speakers at once, as it would in a movie theater. It sounds awesome, much better than I’ve ever heard these mixes sound before, but it does come with the caveat that in order to experience it at its best, you must ensure that your sound system is calibrated correctly, with the rear speakers exactly matching the front in level at the listening position. If they are set to play too loud, as they invariably are in most home setups, then the filtered surrounds will overwhelm the front, and it will be weird and bad. So get out those SPL meters and calibrate your systems again, or else.

Initially I was reluctant to embrace the idea of a mono surround being better than multichannel, but for films of this era it is absolutely more appropriate, since that is how they were actually mixed. It gives a more diffuse and ambient effect and does not have any kind of pinpoint imaging as is the fad now. Additionally, it helps prevent crosstalk from pulling to the side, keeping the viewer’s attention on the screen where it belongs and not out in the room. The 5300 is also able to avoid the center channel pileup of other decoders, where too much of the soundtrack is pulled into the center speaker since they default to decoding in that position; rather, the 5300 preserves panning of signals even if they occur simultaneously in opposite directions. In short, I’ve never heard the positioning of effects in this mix sound so good before, and having experienced it this way, I don’t want to go back. Fortunately, even though the 5300 is rare and long discontinued, you won’t have to own one to experience how good it can sound. Naturally, I plan on recording Empire and Jedi in the same way.

For anybody who has obtained 4K77 and watched it with the 5.1 soundtrack, let me know what you think of this version. I really hope you guys will like this one as much as I do. Hell, even if you don’t like it, let me know what’s wrong so I can fix it, if there’s something I’ve overlooked.