Does anyone know what's different between this version (https://www.cdjapan.co.jp/product/NEODAI-109004, which is advertised as a "4-SACD set") and the other Tower Ravel/Martinon SACD set, TOGE-15074 (https://www.cdjapan.co.jp/product/TOGE-15074, which is advertised as a 5-SACD set")?

I found a picture of the back of the 5-disc version. Also 15 works. Maybe Tower changed order of the works and managed to fit everything on 4 discs?

It's all the same pieces, but newly transferred at 24/192 (the Erato/Warner box was done at 24/96). But this has been out of print for quite a while, so good luck finding it at a reasonable price. Before this release sellers were asking around a $1M for the Erato box.

The reduction from 5 discs (EMI Japan set) to 4 is interesting. Unfortunately, CDJapan shows the Tower Definition set as sold out.
The 24/96 download of Martinon's "Daphnis and Chloe" is available from ProStudioMasters (North America) and HiResAudio (EU), but not Presto UK. Why hasn't EMI-Warner released the rest of the collection in 24/96? Martinon's complete Debussy Orchestral recordings can be purchased in 24/96.

Ben Leggett, if you want more information about the EMI Japan DSD set, you can contact me via email in this site’s list of reviewers.

Details on the Tower Records Definition 4-SACD set, with track listings on each disk here:

https://picclick.co.uk/Martinon-Ravel-Orchestral-Music-4SACD-TOWER-SACD-CD-hybrid-293880441959.html

FYI - Tower is doing a reprint run of this set, slated to ship 4/28:

https://tower.jp/article/feature_item/2023/04/21/1110

Ben/Mark; do you know what recording format was used for this set?

Hiredfox, here is the description on the Tower Japan web page Ben cited (Google Chrome translation). For the Tower SACD set, the transfer from tape was done at 24/192, as Tony Reif mentioned earlier in this discussion. In recent listening experiences, 24/192 has not diminished my enjoyment of recordings that originated in the 1950s-1970s.

New and reprinted from the original analog master tape in the home country.
Digitized from master tape at 192kHz/24bit.

*Regular specification without serial number for release on December 25, 2020
*SACD hybrid board.
*Limited quantity board. Luxurious digipak specification
* 2020 mastering sound source used (SACD layer and CD layer are mastered separately). Mastering Engineer: Kosei Fujita
*Original jacket design used (some other original jacket designs are also used in the commentary)
*Commentary: Hiro Aiba, total 20 pages of commentary

Thanks Mark.