http://www.lddb.com/laserdisc/21671/41086/Jaws-%281975%29
It's the early 90's first letterboxed release. The song replaced is in the background of the beach scene with Brody onlooking the death of Alex Kittner. Seems to be Olivia Newton John according to this thread on the HTF. http://www.hometheaterforum.com/t/322958/jaws-blu-ray-review-very-highly-recommended/360#post_4019185
I have been able to check the audio (and picture) on four laserdisc releases of Jaws, to confirm that the mono audio on the Blu-ray is in fact the original mono from 1975.
The four laserdiscs I checked are:
1. The 1995 Signature Laserdisc
2. The 1991 Letterbox MCA Laserdisc
3. The 1987 Pan & Scan MCA Laserdisc
4. The 1981 Pan & Scan Discovision Laserdisc
The 1995 Laser is the only one at CAV, with the movie spread across 5 sides. The others are CLV, with the movie spread from 2-3 sides.
Listening to Chief Brody's line "Smile you son of a bitch!" on all the mixes, I can hear the "b" just a little bit more clearly on the 1991 & 1987 discs, which matches up with how I hear it on the "Making of Jaws" clip as well. The 1995 and 1981 discs don't have the "b" that clear. (And the Discovision disc is muddy in everything, including both picture and sound) But everything else is identical, down to the subtle bass rumble of the shark closing on Brody just before the blast. Which tells me they are all the same mix. I'm certain my neighbors will be happy after more than 30 repetitions never to hear that surge of music and Chief Brody's shout emanating from my living room again...
I note that the 1991 and 1987 lasers have a disclaimer on them reading "Home Video Version. Some Music Rescored." Which brings to mind one of the big reasons why I didn't keep my lasers or old VHS tapes when I upgraded to DVDs with identical content. One of the nice things with DVD was the relicensing of various songs and musical cues that had been replaced in early video editions. I still remember my shock and delight on hearing Stevie Wonder's "Superstition" on the 1998 DVD for The Thing, where before I had only ever heard a faux disco track on cable or on the pre-Signature laser. I'm not sure what music on Jaws would have been rescored and maybe somebody hear could fill in the blanks on that. Is it the pop music heard on the radio at the beach?
I have to say that the PQ of these laserdiscs, viewed on a 65" screen is pretty bad in comparison to what we have today, not only from the Blu-ray but from the 30th Anniversary DVD. The PQ on the Discovision disc is particularly horrible. Of course, for it's day.... Also, the Discovision disc has a very cloudy physical appearance, which is either from the design of the laserdisc or more likely a sign of its 31 years of age.
Also, the Discovision chaptering is shall we say unique. The whole first side is a single chapter, titled "Hooper arrives at Amity Island." Side Three opens with "Quint shares his experiences aboard the Indiana."
Interesting on the climactic line. I thought it used to be more audible when I was a kid, but put that down to false memories. I recently got the '91 CLV disc and will watch it soon.
Nice that they did the BD mono in DTS, but it would have been better at a higher bitrate. (Not to mention outdo all the pointless work done on a surround remix) Universal has been doing DTS mono tracks.