Audio pops on export and audio mixdown

[Michael Kammes]

Using FCP?

Perhaps you are monitoring on an analog vs digital scale, in which the digital signal is ‘hotter’ than an analog one, thus your layback may have the same mismatch. In the digital realm, when you eclipse 0dB, you distort, which can lead to pops.

I’m also curious why you’re even hitting max volume? Deliverable specs typically reject tapes at max volume, and prefer max volume to be -10dBfs.

~Michael

.: michael kammes mpse
.: senior applications editor . post workflow consultant
.: audio specialist . act fcp . acsr
.: michaelkammes.com

[Mckee Smith]

Its not a monitoring problem – they pops are really there as you can see them in the waveform. And yes we set output levels to peaks of -10.

When I capture from HDCamSR or digibeta, the captured files are fine. We often get tapes with 10 channels of audio on the HDCamSRs and I go ahead and capture all 10 tracks so our ProTools editors aren’t duplicating my capture efforts.

The pops are at 0 or above and last less than a frame. They only appear when exporting AAFs or AIF or WAV or mixdown files from Final Cut. We have tried exporting to our main SCSI drives and to other internal drives in the Mac with the same problem. The pop are random – if I do an export three times, there will be different numbers of pops in different locations each time.

Almost everything we do has at least 4 channels of final audio – mix plus an M&E track. Things which go to HDCamSR tend to have 10 tracks so they can be re-mixed later if ever needed.

Our ProTools people are spending a lot of time trying to fix the pops in AAF files they get from me. My output tapes are failing QA backs there are these random pops in the sound tracks. The pops on the output are NEVER on the actual timeline but only in the mixdown files. We do a mix down of everything before we go to tape because Aja said to.

Any suggestions for fixing the problem would be greatly appreciated.

McKee Smith

[Chad Tingle]

FCP does not like .WAV files but you can sometimes get away with it. It certainly doesn’t like compressed audio formats like AAF’s or MP3’s. I recently had a project where the temp music was sent as .mp3’and the I had random pops all over the timeline. convert the .wav’s to AIFF’s and stay away from the AAF files.

Chad Tingle
Producer/Editor

[Mckee Smith]

These pops appear in the mix down files that are AIF files that are created by Final Cut. I’m not using any MP3s. Occasionally I have a request for WAV files to be exported from Final Cut and these files have the random pops in them as well. But, I don’t use WAV or MP3s in projects.

I use Automatic Duck to export my projects into AAF format, usually an AAF project linked to AIF files. ProTools likes this format. Since I often have 50 minute programs with 10 audio channels these are too big to use the OMF format to export because OMF has a 2 gig file limit.

McKee Smith

[Michael Kammes]

Although I (still) don’t have an answer for the pops, I do have 2 notes:

WAVs not being FCP friendly? I’ve never encountered that. MP3s – yes, definitely, but WAVs have always been a-OK.

As far as OMF exports, I get around the 2GB issue by exporting single audio tracks or dual audio tracks within an OMF to keep under the 2GB file size limit. This may make for 5-10 different OMF files, but since the TC is embedded, they all line up, and Pro Tools can import multiple OMFs into 1 timeline (albeit one at a time).

I have a nice multipage doc I create don prepping audio for PT, if interested: https://michaelkammes.com/audio/prepping-and-exporting-for-post-audio-in-final-cut-pro/

.: michael kammes mpse
.: senior applications editor . post workflow consultant
.: audio specialist . act fcp . acsr
.: michaelkammes.com