There is an article on the BR24 sound decoder installation in the latest Massoth newsletter - only the German version at present, no English translation yet, but as you can copy-and-paste from the pdf it's easy enough to run it through Google Translate; they have this to say about the actual sound files:
"We currently supply in the new sound project for the series 24 of Piko. The sound is based on the principle of the BR 64. The new sound includes two new not previously used an end announcements, as the bursts of steam have been optimized. Of course, this new sound project for the BR 24 also used in the new BR 64."
So really, no difference between the two locos.....
The text of the installation article is this (all copyright Massoth, of course, no infringement intended by copying it here):
"Two weeks ago Piko started the extradition of the new BR 24 of the Deutsche Bahn. For this new model locomotive we have a passive sound project on our proven eMOTION XLS sound decoder in the program. Today we would like to introduce and demonstrate the very easy installation of the decoder.
For digitizing the first Loktender must be opened, here is the installation space for the decoder, as is already a speaker breakdown available.
Once the water tank cover was peeled upward, the use of coal can be pushed out to the front. Thus, to open the tender no screw must be loosened.
The existing electronics on the tender ground is no longer needed. The there the connected cables are gradually connected to the decoder. In the following assignment is to watch out for: GL + (White), GL - (gray), Mot + (red), mot - (blue), + 24V (black), LI-V (yellow), LI-H (yellow) FA1 (green).
Now on the speaker mounting space of the speakers that came with is mounted. After a first functional test of the Tender is completely re-assembled.
Please also note our new MASSOTH TV Episode 23 24 presents the sound of the BR."
So, sounds like a pretty simple job. Hope that may be of some use?
To download the newsletters, go to the Massoth site and select the GERMAN language version (click on the German flag) then go to "newsletters" in the main menu. Because of the slightly weird way their site works, I can't post a direct URL for it. Some newsletters are also available on the English version oif the site, but only the few (seemingly random?) issues that they've done an English translation on so far.
Jon.