Ok, so let's say i'm in the key of C maj. I'm not using ionian, i could be using any of it's modes, but whatever mode it would best fit, then again, I could just be creative. But If I wanted to use the diminished scale in this key, what note would I start on? How would I use it? thanks again, I hope I didn't confuse, thanks.
So I would start on c? because I dk where, but somewhere I think I heard that I should start on B, since it's the beggining of the locrian mode. So if i wanted to used the diminished scale, I would start on c?
If you wanted to play a C diminished scale you would start on C, but your right, start on b.
One thing that you can think of for diminished scales is either 8-note dominant or 8-note diminished

but i dont want to confuse further so just read the thread that bangoodcharolette posted above