Microsoft's forgotten MIDI soundtrack add-in for PowerPoint

One of the more bizarre pieces of software that Microsoft made was the "Custom Soundtracks" add-in for PowerPoint. It let you have dynamically generated soundtracks based on "styles", "personalities", and "bands", and played on a MIDI synth. The music it generates somehow manages to be both simultaneously bland yet surreal; one would wonder what kind of office had a synthesizer in the projector room that could do something like "Mysterious Cave" justice, let alone the content to match it with. Since this is a dynamic music system, one could make an iMUSE-like presentation from a series of slides with their own soundtrack and motif settings.

You can view a demonstration of the add-in on YouTube.

However, Microsoft had quickly forgotten the existence of this add-in. The installer only works for PowerPoint 97, and they had released a small patch to make the add-in work on PowerPoint 2000, had you done an upgrade from 97. If you want to experience it for yourself, but don't have a suitably old machine to dump it onto, it turns out that it actually works on modern PowerPoint, if you do some legwork first.

Instructions

1. Ensure you have a 32-bit copy of Office installed. Office 365 CTR worked for me. Also ensure you have an Office 97 CD. If you're just going to use Office 97, you can skip all of this.
   
2. From your Office 97 CD, copy the \ValuPack\MusicTrk\ folder.
3. Make a registry key called HKLM\Software\Microsoft\Office\8.0\Common\InstallRoot (HKLM\Software\WoW6432Node\Microsoft\Office\8.0\Common\InstallRoot on 64-bit Windows) and set its default value to the install directory of Office. (In my case, C:\Program Files (x86)\Microsoft Office)
4. Run the add-in installer. It'll be tricked into thinking PowerPoint 97 is installed now.
5. Open up the CAB file for the setup and copy the ppmusau.dll file to the Office subdirectory in the folder where Office was installed.
6. (Optionally, make a backup of the ppmusic.ppa file before you do this.) Extract this file's (sourced from Microsoft) compatible-with-newer-PowerPoint version of the add-in to the same subdirectory.
7. Copy the msimusic.dll and msimrt.dll files from the Office 97 CD's \OS\System\ folder to your System32 directory (SysWOW64 on 64-bit Windows.).
8. Start PowerPoint. The add-in should be on the Add-ins tab of the ribbon. Enjoy your new bizarre synth.

Appendix

If you open up the PPMUSIC.PPA file in the VBA editor (Tools->References; make sure to rename your current file's VBA project, since the updated version uses the default name instead of a special one) and poke it in the Object Browser, you can see many of the low-level details of how it works. The PPMUSAU.DLL file abstracts much of it and presents a high-level C ABI way of controlling the soundtrack. Conveniently, the prototypes for the DLL are provided in Visual Basic. Manipulating this outside of the add-in environment could be the topic of more research later.

It seems possible to make your own patches for this, with the DirectMusic SDK, which can be found on a suitably old DirectX SDK. This could be the topic of more research later.

What was Microsoft smoking, anyways?