So, I finally have a working beta version of my low-pass 2 pole resonant filter DMO. It works in DMP, I can get its interfaces in code and tweak it real-time, my audiopaths can reference it and load it, and it works on other peoples' machines (only tested on XP so far)! Very soon I'll put it up for dload so that I can get some feedback (and free testing) from you lot. But first, a quick question for the DirectX / COM code gurus: I'd like to distribute LPF_DMO.h with the .dll in order to expose the interface to DirectMusic programmers. The DEFINE_GUID macro seems like a bit of a pain for users though, what with all the Initguid.h and "can only be initialized once" shenanigans. Is there any reason why I can't just provide this in my header instead? const GUID IID_ILPF_DMO = { 0xd841b97f, 0x5d83, 0x4d76, { 0x90, 0x13, 0xed, 0x83, 0x4, 0xa, 0xe2, 0xa3 } }; Thanks, Andrew http://www.silvershard.com _________________________________________________________________ The new MSN 8: smart spam protection and 2 months FREE* http://join.msn.com/?page=features/junkmail