GM/XG compability

[ady]

Can someone please explain what GM/XG compatibility is? Are these the various MIDI formats? If so, how many are there and how will this affect me when I purchase a keyboard/synth?

[Steve44]

Here's a fairly thorough explanation. Check the bottom for my main advice.

 

GM, or General Midi, is the basic format for standardizing instrument sounds: it consists of 16 categories of 8 sounds each, for a total of 128 patches. In the years following GM's creation, both Roland and Yamaha wanted to expand the soundset, but they each did it in separate ways, Roland called theirs GS and it was usually around 350 sounds, and Yamaha called theirs XG and it has between 400 and 600 sounds or more. Both of them use a Bank-change of some sort to access variations on the standard category, for instance they might take a single organ sound and put 20 different variations on it, or instead of a flute it might have an alto flute. So basically GM, GS, XG are all different patch change formats, with some other special requirements like number of voices and effects.

 

Hardware Compatibility:

Korg's GM modules in the past few years have been the most flexible: they're able to support both GS and XG formats in addition to GM. Both Yamaha and Roland have tried very hard to make their format the one everyone will use. However they just announced that they're going to stop that and that in the future every one of their modules will support both XG and GS. This is especially good since there's a level 2 version of GM out which confuses the format issue even more. So any new modules that come out in the coming months should support all the different formats.

 

The main compatibility issue is for playback of Standard Midi Files. Let's say you want to get midi files of several Prince tunes. They may require that you have an XG-format module or on the other hand a GS format.

 

If you're just buying a module to play use to compose music at home, and you're not sharing your midi files with other people who have different equipment than you, or trying to record midi files of pop tunes and orchestral works, you don't really need to worry about this issue at all. The word "compatible" in this case isn't nearly as big of a deal as your sound card being compatible with your software. If you play a GS format midi file on an XG system it's not gonna blow up, it's just not going to have all the instruments set up properly. Furthermore, there are free software versions of both formats available for download from Roland or Yamaha, so if you need to hear a track you could always use these.

 

The whole GM debacle was not designed for professional use, but rather for consumer use. The GS/XG formats were created to improve upon the original, but most units that focus on GS or XG are still not serious instruments. Even the upper-end boxes, the Roland SC8850 and the Yamaha MU128, - which are useful and do sound pretty good - don't have quite the same synthesis power that the pro instruments do. On the other hand, if you buy a Roland JV1010 (which is only $500) it has some GM sounds, but that's not the main thing you're gonna use it for. Some of the higher end pro-synths like the Korg Triton are including a GM bank just for the sake of having it there, but it's on the side from the main sounds of the instrument.

 

I hope that wasn't too long.

If you have any other questions, feel free to ask...