Crackle can be caused by a interface problem usually drivers. But it can only affect the track while recording, once the track is recorded the interface can not add more crackle. It is possible if you are using a interface as a output you could hear the noise but it would not be on the track itself.
Make sure all your software, drivers and especially third party plug ins are upt to date. And monitor from the iMac.
many thanks for replying. It dosent affect recording really - there is no crackle on playback atall. Its always when im mixing a copy into i-life preview via Garageband. I know its on the track itself because after converting all my songs to itunes and listen on my ipod I have to endure the dreaded crackle in random places. Ive been lucky with some songs but not with others which is really throwing me....It really does seem like its pot luck on the day whether I can master a song and send it to i-life or itunes for a listen.
This is very strange because once it's recorded it is all digital (ones and zeros) if noise is showing up in post it would have to be digital noise being added, this unlikely. I'm guessing a third party AU plugin may be a problem, this is the only way I can think of in adding something to a track.
Are you sure it's a crackle and maybe not just clipping?
ive spent a week on this one song trying every possible version to eradicate the crackle. Ive dumped excess Fx's and tracks that werent really that important. I even heard and saw the crackle show up on one particular LED track volume bar and so I thought great Ive found which AU plugin is causing the prob, which was a synth called Podolski. So i muted this track and did another mix without it.....crackle still on the song.
Can i emphasise that I dont hear the crackle very often or atall on some songs when playing the song in GB...it always comes after Ive done the i-life preview in GB or comverted to itunes to hear it so its hard to tell if its actaully on the song itself or that the crackle is something that is caused by diffrent buffer systems speeds battling with each other. Since you cant alter GB buffer preferences I am lost as to what to do now.
the song has quite a lot of FX and about 10 tracks in total. Ive tried to minimize the amount of mastering FX in GB on this song aswell. PLease any ideas?