Neither Jazz nor the Chrome Web MIDI implementation are finding the Microsoft GS Wavetable Synth on my Windows 8.1 laptop.
Using the same web page, there's no problem on my Windows 7 machine.
A Chrome engineer says: "Chrome just uses aka winmm to control MIDI devices under Windows. I guess the GM synth is not exposed to the API any more, and DXi support is needed to use it.".
The author of Jazz says: "It works fine on my Windows 8 machine". (As I said, its not working on my Windows 8.1 machine.)
I'm told (ultimately by a Yamaha engineer) that the MS GS Synth gets locked if it is accessed by another program first.
Windows Media Player is playing MIDI files okay on my W8.1 machine, so the MS GS Synth is there somewhere.
I tried disabling Windows Media Player and restarting without it. But the problem persists.
I've also tried disabling all the startup processes in the Task Manager, and restarting, but that does not help either.
Where do I go from here?
All the best.