Do you guys have problem's synching in post? it seems no matter how "on" I initially have it. It will slip to about 5 or 6 frames as time progress's. I have a sony recorder as well where this doesn't happen. Am I missing something?

Steve

Do you have PluralEyes?

My Zoom is useless at holding sync, yet my three MiniDisc recorders are spot on over the hour. It may well be an excellent little audio recorder, but it's sync is known to fluctuate pretty wildly.

Tom is absolutely right - the only two things I'd add are "all" zooms at holding sync .... and presumably you're recording at the sampling rate your NLE needs. Zooms default to 44,100 I think whereas Avid asks for 48,000.

No Kelly, Unfortunately I don't have pluraleyes. Although I might breakdown and get it one day.

Thanks guys for the additional info... I guess I'll just have to deal with it for the time being.

Steve

It's an audio drift issue . . . the audio syncs up at the beginning, but progressively goes out of sync. Every device will have a different drift rate (while some have none at all), and there seems to be a lot of factors that can play into why it happens.

I know there's another thread about audio drift somewhere here. You basically stretch the audio track a small amount. It's a lot of trial and error.

This is my solution in Vegas
1. I pull the footage and the audio from my digital voice recorders and place them on the time line

2. I trim the audio file to only what I need, like say if I started it before the camera was rolling I don’t have any use for that so it’s gone.

3. Sync up the audio in the first few frames

4. Then pick a point towards the end of the video, I use the announcement of the bride and groom, and cut the video right on one of the words( you can pull it back out later)

5. Do the exact same thing for the audio file, same word; I use the wave form to help cut… (it doesn’t really matter that you use a word, just that you are ending on the same sound as the video track.)

6. Move the cursor to the end of the video and note how long the video is, like 1:01:09;05

7. Then right click on the audio in the timeline, change the” time stretch/ pitch shift” from none to elastique, check the box that says lock to stretch (Preserves the pitch) and type in the exact length that you got from the video in the new length box.

Takes 2 mins once you have all the steps down, way better than fumbling around for hours like I did the first time

Interesting, David. I do all those steps except for on the last one I check to see if the Zoom clip is shorter or longer. If shorter I right click on the clip and select 'Speed'. Then I try 99.99. If it's still shorter I go 99.98. I just keep tweaking until it matches up.

This is my solution in Vegas
1. I pull the footage and the audio from my digital voice recorders and place them on the time line

2. I trim the audio file to only what I need, like say if I started it before the camera was rolling I don’t have any use for that so it’s gone.

3. Sync up the audio in the first few frames

4. Then pick a point towards the end of the video, I use the announcement of the bride and groom, and cut the video right on one of the words( you can pull it back out later)

5. Do the exact same thing for the audio file, same word; I use the wave form to help cut… (it doesn’t really matter that you use a word, just that you are ending on the same sound as the video track.)

6. Move the cursor to the end of the video and note how long the video is, like 1:01:09;05

7. Then right click on the audio in the timeline, change the” time stretch/ pitch shift” from none to elastique, check the box that says lock to stretch (Preserves the pitch) and type in the exact length that you got from the video in the new length box.

Takes 2 mins once you have all the steps down, way better than fumbling around for hours like I did the first time

That's a great tip, David! I use Tascam recorders, and they have the same drift problem.

I have zoom h4 and zoom h2...make sure you change sampling rate to match up. On mine I have zoom h4 stamina off and wave 48kHz/24 bit...same for zoom h2: menu, rec mode, 48/24.

While the sampling rate shouldn't affect the speed, the default on the H2 is 44 instead of 48, so it's easy to miss that and record at a lower quality.

So, do all the Zooms audio drift?
I was thinking of getting a Zoom to replace my minidisc.

H2 and H4 drift but the H4N doesn't. that's why I upgraded. well worth the extra money to eliminate the drift issue.

H2 and H4 drift but the H4N doesn't. that's why I upgraded. well worth the extra money to eliminate the drift issue.

Thats good to know Pete, thanks.

I've experienced this with every digital recorder I've used: Mini Disc, iRiver H120/320, Zoom H2, Sony PCM-D50, Tascam DR-2d.

Even though you're recording the same thing the internal mechanisms of different devices may move at a slightly different speed. Usually the difference is not drastic. Usually for a 1 to 1 1/2 hour segment the audio source I use might drift about 1/2 second by the end. With digital sources the drift is constant and easy to fix.

In Sony Vegas line the new track up with your camera's audio track and use some reference point at the beginning to sync them. A hand clap or sharp, quick noise works well. Sometimes it might take a little effort to get this part down just right. I usually pan each track to a different channel and use headphones so I can hear each clearly and know they are in sync.

Then go to the end of the tracks and find a noticeable spot at the end. I use a little trick I came up with of finding my reference spot at the end and holding down shift and using the arrow key until I get to the same point in the other audio track. This give me a loop region that is exactly the space of the drift.

Then drag that loop region to the end of your new track, hover your mouse at the end of the track, and hold down the CTRL key. You'll see the ~ symbol appear. Drag the track left or right the stretch or shrink using the loop region as reference and it should be spot on after that.

There are other ways of syncing two audio tracks but using Vegas and the method I described I'm able to sync multiple tracks pretty quickly and without trouble.

There are other programs like Wavelab or Adobe Audition that will change the length of a file for you but it involves calculating the difference and inputting figures to change the length.

Thanks Stan for that information,
I use Edius BTW.

Thanks again.

A clapper slate at both ends of the take makes it easier adjust length. Clap a slate at the start as usual plus clap a tail-slate at the end. Line up the visual clap and the waveform spike at the start of the take, move to the end, and line up the tail-slate spike by dragging it.

A tail slate definitely makes it easier, but my older H4 exhibits variable drift. So even if you've lined up both slates properly, looking closely at different points in the middle of very long takes the audio may be a little ahead or a little behind or right on the money. Some smaller cuts during the program are usually required to keep things as close as possible throughout the whole run.

My newer H4n does much better. It's not off by much and seems to be consistent and easier to adjust for.

A tail slate definitely makes it easier, but my older H4 exhibits variable drift. So even if you've lined up both slates properly, looking closely at different points in the middle of very long takes the audio may be a little ahead or a little behind or right on the money. Some smaller cuts during the program are usually required to keep things as close as possible throughout the whole run.

My newer H4n does much better. It's not off by much and seems to be consistent and easier to adjust for.

Definitely. The right way to do it is to use pro gear such as SD recorders that have a very accurate timebase to begin with or even better, cameras with genlock input and audio recorders with wordclock input plus the necessary outboard gear like Lockit boxes to sync them all together to a common timebase.

A tail slate definitely makes it easier, but my older H4 exhibits variable drift. So even if you've lined up both slates properly, looking closely at different points in the middle of very long takes the audio may be a little ahead or a little behind or right on the money. Some smaller cuts during the program are usually required to keep things as close as possible throughout the whole run.

My newer H4n does much better. It's not off by much and seems to be consistent and easier to adjust for.

Any digital device shouldn't do that. Variable drift is a trait of analog recorders. Something is not right if the drift isn't constant.

In theory, variable drift simply means that the time base isn't perfectly stable. And nothing is *perfectly* stable... although an atomic standard comes reasonably close. ;-)

Whether or not the variable drift is noticeable is another question. Even a crystal timebase is subject to some drift, based on temperature. (Most broadcast transmitters, for example, have their crystal timebase inside a temperature controlled oven, to improve the frequency accuracy and stability.) So if a given recorder has an inexpensive crystal at ambient temperature, or, worse yet, a lower cost ceramic resonator, it can potentially drift around over a long period of time.

Plus we sometimes forget in this discussion we're always talking about TWO timebases, not just the one in the audio recorder but also the one in whatever we're matching it to.

I'm also referring to 90 minute live recordings where there has been minimal warmup time for the equipment before recording begins, and the air conditioner cycling off and on many times during that period, with very noticeable differences in the air temperature during these cycles.

Even two (or more) cameras of the same make and model will drift some over time w/o being 'gen-locked'. For continuous multi-camera A/V recording, it's best to use a tri-sync system... if it's in the budget.
For feature film type work, where there are many short scenes and takes, drift is usually not an issue. Even with the notoriously flaky RED camera and an H2.