You are experiencing what is known as latency. Latency arises from the time it takes your computer to convert the microphone signal to digital, process the signal, and convert back to analog voltage so you can hear it. Latency is unavoidable when working with software, but there are some things you can do to minimize your latency.
What soundcard/interface are you using? If using ASIO drivers, you can reduce your latency by setting your buffer size (Live's Preferences) to the smallest you can get away with without having audio crackles going on.
As for the delay you experiencing....could it be latency + feedback? Like if you hit the mic, and it takes 500 ms for the sound to come out of the speaker, then the mic picks that delayed sound up and feeds it back out the speakers with another 500 ms delay?
EDIT : Ooops, I didn't see all the other replies before posting this...
Voice effects in live
In case you haven't already done this..
Stick your headphones into an unused output on your soundcard then set 'cue out' on the master channel to the said output - stops irritating little cable changes just to get the metronome through yer headphones (and not the speakers, where it is picked up by the mic.)
Stick your headphones into an unused output on your soundcard then set 'cue out' on the master channel to the said output - stops irritating little cable changes just to get the metronome through yer headphones (and not the speakers, where it is picked up by the mic.)
no, YOU should get out more!