Questions about sound in Red One

[Nick Shaw]

Surely if you're shooting 120fps, you aren't going to be using sound recorded at 120fps and played back at 24fps (if that's your projection rate)? Probably anytime you shoot "off-speed" you are going to be post-processing sound in some way, rather than using "sync" sound. "Fast" or "Slo-mo" is a visual effect, and rarely if ever will the sound be recorded and used at the same frame rate as the picture. At least I can't think of any examples!

I agree in the main. I did say in a later post in the thread that most overcranked shots are done MOS. But sometimes it can work as an effect. I cut a piece recently with some 100fps boxing shots. The sound recordist had been running the DAT continuously during the takes, with the intention of having a wild-track. I synced up the audio manually, and slowed it to match, and the result was very effective. The director was surprised how effective, and said he would record sync sound on all overcranked shots in future.

Nick

 

[ericyoung]

I agree in the main. I did say in a later post in the thread that most overcranked shots are done MOS. But sometimes it can work as an effect. I cut a piece recently with some 100fps boxing shots. The sound recordist had been running the DAT continuously during the takes, with the intention of having a wild-track. I synced up the audio manually, and slowed it to match, and the result was very effective. The director was surprised how effective, and said he would record sync sound on all overcranked shots in future.

Nick

Yes, is that the same as recording sound at "100fps". The DAT was just running at normal DAT speed. When you slowed the sound to match, were you really slowing it down an exact 24/100th of full speed, or just until it "felt" right. There was no need to have matching timecode on sound and picture for this purpose.

That's not to say that, when shooting offspeed, recording sound at the same time isn't useful. I would always record sound if available for exactly the reason your director found. But I wouldn't call that "sync" sound, just a wild track recorded at the same time. I'm probably just being overly pedantic.

I think the original query was about having recorded sound somehow be recorded at the same speed as picture frame rate so that it would be simple to sync up as they would have the same timecode? (I'm too lazy to go back and check!! )

 

[Nick Shaw]

Continuing the pedantry, I WOULD call what I had 'sync' sound, as I did indeed slow it to 25% speed and sync it with the images. I had no time-code though, and had to do the syncing manually.

If you are interested, you can see the film HERE. Actually I just watched it again, and the off-speed sound (only used on a few shots anyway) is pretty inaudible in the final mix, particularly on the web version.

Anyway I'll stop the pedantry now!

Nick

 

[Stokestack]

Why would you use an outboard A/D when the camera has one in it? It just seams like extras stuff to carry and get tangled.

I can definitely understand digital in, but that's only if it coming from a sound guys high quality digital mixer that has better pre-amps and A/Ds.

Hey David,
doesn't your second statement answer the question in the first?

If you shop around for small flash-based field recorders, you find that many of them are condemned in reviews for having noisy preamps. And these are devices that are devoted entirely to audio. Do we consider the Red camera to be primarily an image-acquisition device, with limited space and resources to devote to audio? I would think so. If so many vendors are having trouble getting decent preamps into dedicated audio recorders, this gives us reason to worry that the ones built into a camera might suffer from similar limitations.

Thus the desire for a digital audio input, which frees us from such limitations while letting us sync audio at the point of acquisition. And a digital audio input requires an outboard A/D converter. So I'm perplexed by your question.

 

[craesmeyer]

After read, and read all the opinions i would vote to Red had an 2 channel analog input and another 2 channel digital input... It seems more interesting and future-proof than the actual solution EXCEPT if the actual preamps and A/D's in camera are really good...

 

[Len M.]

All four audio inputs are mic/level switchable

Are they well matched in gain? How close are they matched?

All inputs support 48V phantom power for mics

How much current can they supply per channel?

Each audio input is sampled at 48KHz at 16 or 24 bit depth

What are the noise and dynamic range specs on the mic inputs?

Are all four inputs truly sync'ed at the sample level?

Thanks!


Len Moskowitz
Core Sound LLC
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