Question - What's the difference between using the WADs and the OP2 file with DooM?

[iogamesmaker]

Hi, first off, thanks for making this project. Don't understand why this isn't more known, it's great sound quality for free!
My question is simple: is there any difference between using GENMIDI.OP2, DMXOPL.WAD or DMXOPLV.WAD?

Thanks.

[Wohlstand]

WADs are basically packages with the bank included and they can be linked to the running Doom game as a mod.