Digital clipping where there weren't before

[naushikaa]

Hi there,

 

I've openned up some old wav files to listen to, and there's clipping where there wasn't before. Random places, scattered throughout the songs. This has happened on many tracks. They are stereo interleaved files bounced from ProTools. I noticed when playing them on windows media player, so I imported them into a sequencer to check, and yep, those nasty rectangular waveforms are here and there.

 

To clarify, I've listened to them in their current state many times in the past (5 years ago) and the clipping wasn't there. However, they've been transfered and copied from computer to computer.

 

Firstly, what could have caused this, and secondly what is the repair solution? I'm using Ableton Live at the moment.

 

Thanks in advance!

[Phil O'Keefe]

To clarify, I've listened to them in their current state many times in the past (5 years ago) and the clipping wasn't there. However, they've been transfered and copied from computer to computer.

 

To be honest, I'm at a loss as to what could have happened. If you were doing straight digital copies, with no gain adjustment or compression or limiting - basically not changing ANYTHING - then there's no reasonable explanation for how clipping "got on to the files".

 

Do you have the original source files - either the DAW session files or the original two track mixes? If so, I'd revert back to those. If these are your only copies, you're in a world of hurt. You can either go in and lower the overall gain by a few dB across the entire file, then draw in the clipped waveforms, or use a program that will "guess" at it for you... but it's always less than ideal, and frankly a great big pain in the posterior if there is a lot of clipping throughout the song.

 

Sorry...

[naushikaa]

Yeh, the problem is exactly that... I'm not in possession of the original session files or the like. These are it.

 

Someone elsewhere told me that weird changes like this occured when transferring audio data onto his/her new Vista machine. Something called "easy file transfer" or the like. I run Vista too, and these files came from somewhere else after I first installed Vista. Perhaps Vista used this same way of transferring... can't remember since I wouldn't have expected something like this!

 

I don't think Ableton Live allows me to draw in the waveform like ProTools can. Can somebody recommend software that does this?

 

Free to use would be good since I HOPE this will be the only time I need to do this.

 

Thanks.

[WRGKMC]

Most likely you have latency crackle and its not the files at all. You can try playing back each track with something like windows media player, if they're clean playing back that way, then try adjusting your latency and/or buffers up and the noise should go away.

 

I get this problem if I have my latency set too low and it drove me crazy till I found the cause. It sounds exactly like an over driven signal when its on the edge.

 

If it truely is over driven wave files, I've had success using Waves X Crackle to remove the noise if its not too bad. The other day I did some studio rearrangements moving equipment. I rewired alut of stuff and ended up having vocal mic gains set way too too hot. The was digital distortion all over the place so I processed the wave down to about -3dm then used the waved plugin and got rid of 99% of the crackle.

 

Be sure to drfrag then move the file over to your current projects folders. It may be the files scattered all over the hard drive and the drive heads having to jump all over the place to play bits an pieces of it too.

[Zooey]

I'm also confused about how it could happen. That would be like copying a Word document 5 or 6 times, opening it up, and finding that a bunch of words were mysteriously misspelled. It just doesn't happen. There must have been some process performed on the wav files (encoded and decoded to some compressed format maybe?)

[WRGKMC]

Exactly.

 

I dont know if you've ever tried playing back a stored project on a partition of the main drive before. I know with Sonar it will ask if you want to copy it to your existing wave file partition first because it knows it wont play back right. If you choose to play it from its existing location, it will have all kinds of studders digital noise etc because the drive heads are trying to play the files from the partition and running the OS and program from the main drive working the heads to death.