well, that's just lovely.

I'm surprised kinda, this is supposed to be good at what it does (granted it was only a few hundred bux, but still, THAT'S A FEW HUNDRED BUX.

I suppose it could be the DVX's that I shot with, but I'm pretty suspicious now.

Thanx for the info Farss, I've gotten it synced up by strategically slicing it at a few dead spots and aligning it again.

Dave

You can also use Vegas to time stretch.

The ONLY way to get everything 100% locked is with cams that'll lock to to external reference and audio gear that runs off the same master clock as the camera(s). Expect all this to cost $1000s, just the SPGs alone aren't cheap.
Better kit that internally runs more accurate clocks doesn't cost as much and gets you to the 99.9% mark.

I realize it's not SMPTE but I've done several multicam recordings using 3 - 4 Sony camcorders (VX2000s, Digital 8, A1U) synching them to audio from a rack mounted CD recorder and they stay in sync for at least 30 minutes.

I suspect it's not your camera.

Listen to Bob. The best way is to sync the head, then sync the tail. Use time stretch to sync the tail. After that, everything should line up, unless you experienced some stepped dropouts or the time clock on one of your devices is variable...which is really a scary thought..

I have a Zoom H4, which I just love, and one of its uses I was looking forward to was this.

I've succesfully synched mini disc audio by time stretching in the past, so I hope that this will be just as easy.

Dave - how much was your synch out, over what duration?

Peter

Hey Peter, across 1 hour of footage (the longest length of footage I've synced with this device) it was probably only off by about 1 second or so, but it's still irritating.

Dave

That's not that bad. One tip, if you know you'll have to do this then turning off any AGC on any audio helps keep the waveforms looking vaguely the same and that makes syncing way easier.
It might not be the audio recorder either. There's no requirement for the cams audio to be exactly 48,000Hz, I've read the Canon Xl1s run at 48,001Hz which makes syncing them to Sony footage a problem in post.

I've read the Canon Xl1s run at 48,001Hz which makes syncing them to Sony footage a problem in post.

Oh wow! That's amazing! Bob, it is these tiny bits of real facts that can skew and twist one around. Amazing, truly amazing!!

The Zoom H4 is so new, it takes a newbie to find these things out. My MiniDisc recordings would drift from time to time. Looks like the Zoom does as well, although 1 second isn't really a big deal. Annoying, yes, but certainly fixable.

On a side note, the iRiver's I've been using for the last couple of years to record dozens of events have never lost their sync. Go figure.

Not something I discovered off my own bat, from memory I first read it in a post by Spot. There's more entertainment from another thread in this forum about Locked Audio, now that's something to really twist the old grey cells.

Bob.

Wow! I just got a Zoom H4 in view of replacing my portable DAT recorder for dual system video and sound. The Sony DAT is 12 years old and has about 1200 hrs on the heads use meter, figured that putting in new heads would cost more than the Zoom, so it was apparently a no-brainer. Plus not having to capture audio into the pc on real time terms. Now there's some serious testing to be done....

Resyncing hasn't been much of a problem. There have been occasions when the in-house audio tech didn't bother to pack the DAT tape before use. Can't tell you how close I've come to committing grievous bodily harm on another person on those rare, but not that rare, occasions.

I have also used CD recorders for 2 channel audio with mulitcam recordings. The cd audio is rock solid every time. I wonder if the Zoom would do a better job at 44.1? Maybe a more accurate clock at that rate?

JAB

I've read the Canon Xl1s run at 48,001Hz which makes syncing them to Sony footage a problem in post.

I know next to nothing about practical audio compared to people in this forum, but I have an EE degree and worked almost five years in two test and measurement divisions at Hewlett-Packard. Bottom line is that unless you have an oven controlled crystal oscillator that has been laser trimmed (which you definitely do not have in any camera at any price), you will not get exactly the same frequency in two different cameras. That is not what crystal control is all about. What the crystal source WILL ensure (as long as temperature stays relatively constant) is that the frequency will not vary over time (remember wow and flutter?).

Thus, Bob's original statement is exactly correct: the only way to have the audio on two cameras start and stop at the same time is to sync them at the shoot. However, since the crystals are likely quite constant, it should only require syncing them at the beginning and then doing a quick Ctrl-drag of the trailing edge of one event, and all the points in between should be quite accurately in sync.

WIth reviews from users like this:

http://www.zzounds.com/item--ZOMH4

I wouldn't touch the zoom..

ken

Really, stretch-syncing is no big deal. I work with Minidisc, and so I'm stretching clips all the time. Takes just a few seconds.

The problem is a bit more complex than even that. In a camera you have two clocks, one for the DV video at around 13.5MHz and one for the video at 48KHz. My understnading is that the DVCAM spec requires them to be locked at an exact mulitple, DV doesn't require this, that's why you can potentially get A/V out of sync from just one camera. The NLE after capture faces a problemo, you might have 60:00;00 of vision and 60:01;15 of audio for example. So it has to do some work to get the A/V into sync.
From what was said by othera in a Locked Audio discussion it's a fairly complex task to get the clocks in a camera at the right frequencies and locked, so the cheaper DV cams cut a few corners. By my understanding in a two camera shoot you can have 4 clocks running, two video clocks and two audio clocks so even keeping vision in sync can be a problem. Even when you do get vision in sync you can still be left with an error of upto 0.5 frames. Not much until you do a dissolve with something moving fast in the frame, then the error can be quite noticeable.

Bob.

Which particular comments put you off, Ken?

There were plenty of good reports. One thing acknowledged widely is that the sound this thing records is fantastic quality.

You may not want to, but I touch my Zoom H4 a lot ......... it's by far the best thing I've bought since the Z1, two and a half years ago.

The main thing I feel with this synch issue is gratitude that Vegas makes correction so easy.
Peter