I was surprised to detect the Elvis - Aloha From Hawaii - Pioneer Artists PA-96-571 only has analogue sound and no digital sound (although this is mentioned on the sleeve)

Also Pioneer did re-release at the end 1996/1997 a lot of old titels (do they have digital sound?)

There were only a few music titles re-issued:

PA-96-571 Elvis Presley: Aloha from Hawaii (1973)
PA-96-572 Elvis Presley: 1968 Comeback Special (1968)
PA-97-575 America: Live in Central Park
PA-97-576 Kenny Loggins: Alive (1981)
PA-97-579 The Tubes: Video (1982)
PA-97-580 Knack: Live at Carnegie Hall (1979)
PA-98-584 John Lennon: Sweet Toronto/Keep on Rockin' (1998)
PA-98-585 B.B. King: Live in Africa (1974)
PA-98-588 Pointer Sisters: Live in Africa (1974)

I have some of these and they did have digital sound. According to LDDB.com some even had AC3.

Pioneer reissued a lot of their music releases with digital sound, like David Bowie Serious Moonlight, Duran Duran Video's, the 8-inch Madonna disc, 8-inch Diana Ross, Dolly Live in London, Queen Greatest Flix, Stevie Nicks, etc... Some, like Duran Duran and Madonna are very hard to find - Pioneer didn't make a big deal of their releases and just put them on the market, usually with the same old catalog numbers and a small digital sound logo somewhere on the jacket.

The ones I mentioned previously have new catalog number as opposed to re-using the old catalog numbers and they also have Dolby AC-3 digital audio sound in place of the analog audio on channel 2.

I can confirm that is the case for the following which was released in 1998 as I have a few copies of that disc - one sealed and one opened:
Pointer Sisters: Live in Africa (1974) [PA-98-588]
It mentions on the back the 5.1 Dolby Digital was created from the original mix at POP Sound by Ted Hall.

So it seems for titles where the audio was enhanced to AC-3 there were very few titles issued but any that were had new catalog numbers.

Cool. There can't be that many 5.1 audio titles out there on LD, it isn't even standard on DVD/BD. I know of Fleetwood Mac The Dance is AC3, the DVD is too though. DTS issue was canceled. I don't see a specific search for 5.1 music titles so hard to say how many.

EDIT: Just went thru, copy/pasted. I think this is all AC3 music titles: (very limited selection)

ID4054WC Alanis Morissette: Jagged Little Pill Live (1997) AC3 1997-07-02 NTSC USA
WPLR-49 Alanis Morissette: Jagged Little Pill Live (1997) AC3 1997-07-25 NTSC Japan
PA-97-575 America: Live in Central Park AC3 1997-05-27 NTSC USA
PA-98-585 B.B. King: Live in Africa (1974) AC3 1998-05-12 NTSC USA
ID4155WO Fleetwood Mac: The Dance (1997) AC3 1997-11-05 NTSC USA
WPLR-62 Fleetwood Mac: The Dance (1997) AC3 1997-10-25 NTSC Japan
ID5516ER Janet Jackson: The Velvet Rope Tour (1998) AC3 1999-03-09 NTSC USA
ID4377WO John Fogerty: Premonition (1998) AC3 1998-09-16 NTSC USA
WPLR-93 John Fogerty: Premonition (1998) AC3 1998-10-15 NTSC Japan
PA-98-584 John Lennon: Sweet Toronto/Keep on Rockin' (1998) AC3 1998-05-12 NTSC USA
ID5513ER Joni Mitchell: Painting With Words and Music (1998) AC3 1999-03-30 NTSC USA
ID4164WO K.D. Lang: Live in Sydney (1997) AC3 1998-04-29 NTSC USA
PA-97-576 Kenny Loggins: Alive (1981) AC3 1997-10-28 NTSC USA
PA-97-580 Knack: Live at Carnegie Hall (1979) AC3 1997-12-16 NTSC USA
PA-96-568 Queen: We Will Rock You: Commemorative Release (1981) AC3 1997-12-16 NTSC USA
ID4165WO R.E.M.: Road Movie (1996) AC3 1997-12-17 NTSC USA
PILW-1248 Spiritual Earth: Mt. Fuji (1997) AC3/CAV 1997-11-21 NTSC Japan
LD 15080 The Beach Boys: An American Band (1985) P&S/AC3 1995-12-26 NTSC USA
ID5472ER The Bee Gees: One Night Only (1997) AC3 1999-02-16 NTSC USA
36440 The Rolling Stones: Bridges to Babylon: Live (1998) AC3 1998-12-01 NTSC USA
ID3646CA The Rolling Stones: Live at the Max: IMAX (1991) AC3/THX 1996-12-18 NTSC USA
POLP-1040 The Rolling Stones: Rock and Roll Circus (1968) AC3 NTSC Japan
38781-1003-1 The Rolling Stones: The Rock and Roll Circus (1968) AC3 1996-10-15 NTSC USA
PA-97-579 The Tubes: Video (1982) AC3/CAV 1998-01-13 NTSC USA
ID4016ER Tina Turner: Live in Amsterdam (1996) AC3 1997-10-15 NTSC USA
LV 32228-A U2: Rattle & Hum (1988) P&S/AC3 1995-10-10 NTSC USA
PILF-2502 U2: Rattle & Hum (Tamashii No Sakebi) (1988) AC3 1997-12-21 NTSC Japan
ID4166WO Van Halen: Video Hits vol.1 (1996) AC3/+CAV 1997-12-24 NTSC USA

The PILW-1248 Spiritual Earth: Mt. Fuji (1997) AC3/CAV 1997-11-21 NTSC Japan

Is actually a documentary scenery disc. I have 2 LD from the Spiritual Earth series. Also one of the Moodtapes scenery LD (which I have) has a AC3 track as well.

Moodtapes: Pacific Surf (1995) [ID3391MT]