Audio Sync Drifts When Recording Podcast

[jordank93183625]

Hey Everyone!

I'm recording a 4 channel podcast using Adobe Audition and a Behringer interface. We started to film our podcasts and I've noticed that the audio we are recording in Audition falls out of sync with the video when editing in Premiere.  I've also noticed every so often there are very minor pop/clicks in the audio recording that seem coincide with the sync issues.

I've never had these issues when recording on an external audio device such as the h4n, so I'm fairly confident the issue is coming from Audition.  Additionally, I've tried 3 different interfaces (2 Behringer & 1 Presonus) and the issue still occurs.

I've been able to fix this issue by going through my timeline and manually syncing the Audition audio to the camera audio, but I would like to fix this so I don't have to do that.  Has anyone else had this problem and found a solution?  If not, do any of you audio engineers have any possible solutions?

Here's an example of a pop/click that I believe is causing the issue.  It's right before the man says "movements".

Dropbox - Audio Sync Issue Example.mp4

Audition Settings

• Sample Rate: 4800hz
• I/O Buffer Size: 512

Interface

https://www.amazon.com/BEHRINGER-U-PHORIA-UMC1820-Black-8-Channel/dp/B01EXI8Y9S/ref=sr_1_3?ie=UTF8&q...

Any suggestions would be greatly appreciated!

[SteveG_AudioMasters_]

jordank93183625  wrote

I'm recording a 4 channel podcast using Adobe Audition and a Behringer interface. We started to film our podcasts and I've noticed that the audio we are recording in Audition falls out of sync with the video when editing in Premiere.  I've also noticed every so often there are very minor pop/clicks in the audio recording that seem coincide with the sync issues.

How have you synced the bit-clocks between whatever you're recording the video on and the Behringer? Okay, I admit that that was a loaded question, because you haven't - there's no word clock input on the Behringer, so you can't. What you need to understand here is that just because it's 'digital' that doesn't mean it's perfect - there is in fact quite a wide (in sync terms) clock tolerance allowed for audio and indeed video recording. The only way you can guarantee that two separate recording devices with their own clocks will stay in sync is if you designate one as being the master, and lock the other one to it. This is what professional kit allows you to do.

As for the pops - well this could easily be sync-related - it all depends on exactly how you've edited the results. What happens if you run two almost-synchronous sources together is that all the time the clock pulses are less than one pulse apart, it will sort-of work. The moment they get to the whole-pulse point - well that's when you get a pop.

There are no good solutions to this, other than the one I've already mentioned. Quite often, material can get a significant amount out of sync - the drift over an hour can easily get up to a couple of seconds with equipment like Behringer produce - and that's an error of only about 0.01% on the clock speed. The normal 'fix' involves either stretching or shrinking the audio to fit the video (which still doesn't take account of local drift), or simply re-syncing the audio when the drift gets to an unacceptable state.

There's loads of information about this if you do a search using a term like 'audio word clock sync'.

[ryclark]

How are you recording the video for your podcast? Is it going onto a separate video camcorder and importing the video files into Premiere or are you somehow capturing it directly into Premiere? And then you get the playback sync issues when you have imported the Audition audio file into Premiere alongside the video?

Also I presume that you are using the supplied Behringer/Presonus ASIO drivers when recording into Audition?

[SteveG_AudioMasters_]

It's technically possible to capture directly into Premiere, but you still need either a direct stream from a camera into a port, or a capture card. However you do this, the camera provides the sync source to which the capture device locks (the device either being part of the camera or a standalone box). If you use the standalone box method and it's one of the cheap ones, then they won't lock a separate audio feed into the video either; you need at least a Canopus one to do that, otherwise the audio remains unlocked.

There is no way, regardless of what drivers you use, of locking the Behringer to the video capture or vice versa. However you use it, you'll end up with no sync, and the drift problems.

[jordank93183625]

Hey Ryan!

I'm recording the video to multiple cameras and I am then importing the files into Premiere for the multi-cam edit.

The current audio interface I'm using does not require drivers when using a Mac. They advertise it as "plug and play"

[SteveG_AudioMasters_]

jordank93183625  wrote

I'm recording the video to multiple cameras and I am then importing the files into Premiere for the multi-cam edit.

So basically you've got a load of sync sources here, but that doesn't matter, as presumably you are lining up the cuts in Premiere, so they appear to keep time - even though in reality they'll all drift slightly, but you won't notice this, because you have nothing to reference this against.

The most sensible thing you can do in this situation is re-sync the audio every time you change the shot in Premiere. I realise that this is a pain, but unfortunately it's going to be the most successful method by far of keeping the drift minimised.

[jordank93183625]

Hey Steve!

Thanks for the detailed reply!  I'm sort of confused by this concept being that I've been recording audio on external audio devices for quite some time now.  I own an h4n and have used that one numerous long interview style shoots and have not experienced any audio drift issues. Why would using an audio interface introduce this issue?

I understand the concept of using a word clock as a "best practice" to avoid the possibility of audio drift, but I've had this issue with every recording I've done.  This is leading me to believe that something needs to be tweaked within my Audition project.

[SteveG_AudioMasters_]

jordank93183625  wrote

I'm sort of confused by this concept being that I've been recording audio on external audio devices for quite some time now.  I own an h4n and have used that one numerous long interview style shoots and have not experienced any audio drift issues. Why would using an audio interface introduce this issue?

I understand the concept of using a word clock as a "best practice" to avoid the possibility of audio drift, but I've had this issue with every recording I've done.  This is leading me to believe that something needs to be tweaked within my Audition project.

It doesn't have anything to do with either clock source on its own - which is why you haven't had trouble before. It's the fact that you are using two clocks (one video, one audio) and they don't keep time with each other - hence the drift. The only way to make them keep time with each other is to synchronise them, and there is no mechanism for doing that with the Behringer - even assuming you had the camera sync source available.

There is nothing you can tweak to avoid this at all - it's happening whilst you record, and it's uncontrollable.

[the_carmichaels@mac.com]

I have imported multi track recordings into Audition and have noticed that some tracks change their playback rates on their own! Drums were recorded at the same time but the snare and the kick go out of sync. When I look at the track properties, i notice that one is playing at 100% while the other is playing at 98 or 97 %. I did not adjust it, Audition seemed to do this on its own so make sure your playback rates are locked in at 100%