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Feeding TC to Zoom and F5


Lefteris

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Hi guys,

 

I'm new both here in this forum and in the sound mixing profession so please go easy on me.

 

I got a call for a job, no-budget feature, got hired and then they decide to tell me they want TC. Now, I'm using an SQN with a zoom h4n and i've been trying to figure out how to do this as I've never done TC before.

 

I read plenty, and still got more to go, but i keep coming to the same questions that remain unanswered so I'm hoping somebody here can clarify things for me.

 

Here goes:

 

1. How bad, if any, will noise from the TC track bleed to the audio track? And how do I stop it from bleeding? (i read somewhere to keep the volume in the middle but I wasnt convinced)

 

2. Do I set the camera to DF or NDF?

 

3. I assume both the camera and the zoom will be "slaves" to the TC generator. I checked the F5 manual and it doesn't have an option for slave/master. Do I set it as master or will it automatically accept the TC from the generator?

 

4. Any other issues I should be aware?

 

Any answers would be greatly appreciated. 

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Thanks for the advice Chris. I think you missed the part were I said they hired me first and then they told me about TC 1. I wrote my kit 2. I would if they had one 3. I wasn't aware the zoom could be a master (sarcasm in case you didnt get it). If I could have a 744t I wouldnt be asking about sending tc to a zoom.   

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Lose the Zoom (it is an amateur toy and should not be used for this), the camera audio is far superior.  The camera generates its own timecode, just feed your audio to the camera and let the camera department deal with the timecode specs. Without a professional timecode recorder you are asking for a world of hurt.

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What were you going to use to generate TC? If your kit is a mixer and a zoom, there's no TC generator in that equation. If there is no chance to upgrade the kit, i would try to feed primary audio to the camera and maybe run the zoom as "better than nothing" backup. They can always use plural eyes to help sync it.

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There is a decent danger of TC crosstalk on the inputs of the Zoom--you're right to be concerned.  Regarding your approach to sync, I'd try to find out if they have an editor or post supe on yet and work it out with them.  Like you, I don't think I see the need for TC on a production where there is only a 2 track recorder available--a feed to the camera, good notes and a clap slate might work out fine.  If they insist that you work with TC, then you will have to get a TC capable recorder, and explain to the production that they will have to pay for it.  Having done that you will then have to figure out how to keep your recorder in TC sync with the F5--to do this right you'll need some variation on the Lockit/SBT/TC Buddy method.

 

philp

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Besides all the obvious from the above responses - there's this:

 

10 kHz, -0.5 dBFS sine wave on the Zoom H4n (rec-level 40 with 18 dB pad)

zoom-10khz.jpg

 

Quote:

 

Not to the surprise of anyone this distortion is audible in everyday recordings - not just in test setups. It may not be obvious at first but in direct comparison to the original or a good recording from another device the Zoom will sound harsh and unpleasant with overemphasized highs.

 

End Quote

 

From:  http://www.martin-doppelbauer.de/audio/fieldrecorder/part2/

I think this is the last of their worries.... LOL  :-

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Thanks for the input everyone.

 

Johnpaul & Philip, I would probably have been using the Betso sbox with transceivers.

 

Rob & Jim, I am aware the zoom is a toy, i have worked with many other recorders. Unfortunately I can't afford, and don't have the clients willing to pay for, a 7-series sd or a zaxcom just yet.

 

I did consider sending tails to camera, as most of you suggested, my only worry being the restriction to movement. But I guess I can work around that easier than feeding tc to the zoom. 

 

Again, thanks for the input.

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I agree about sending L&R to the F5 out of the SQN, an omitting TC from your part of the equation.

then, get or make a cable to tap the unbalanced output of the SQN as a reference track source for your zoom, if you still feel you need it.

 

If you need more reach, get an extension cable for your tails... or if there is really no budget, 2 xlr cables for L&R.. and *maybe* a 3.5mm extension cable for the return...

 

the dedicated breakawya extension cable should be rentable somewhere in your part of the world.. maybe from Pinknoise?

or ask SQN.

 

basically, you are using a great sounding mixer, and are feeding the lesser quality recorder available to you..

 

Do make sure you confirm the best level settings for the F5... I am finding that is a bit fiddly to set up on my current shoot...

 

I will be doing more testing on that tomorrow.  

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A lot of us spent years cabled to cameras. Unless it's a specific shot that's nuts, they can handle it. Usually a monitor cable is coming off anyway. Heck, there were law enforcement documentary tv shows that had mixers cabled to camera in the heat of the moment while running in bulletproof vests. I worked on one, and that's just how things were done.

Let's be blunt, and no offense intended. If they hired you, and your kit, they were probably unable to get people with more extensive gear for the rate. If post wants TC, let them find the money to rent you something. Not all post workflows can even handle TC on an audio track. Having a 702T instead of the Zoom is not going to make your life any easier. It won't make your mixing any better. It won't get you better range on your wireless mics. Same goes for TC slates and sync boxes. Let them find the money.

and for down the road...... That's how I bought my sync boxes. I once negotiated a deal to mix a film, and days later post insisted on sync boxes I didn't have, so I let them make the case to the line producer. They can say "syncing by hand will cost you this many days of busy work, versus a sync box". Those are numbers I don't know, so I can't argue them. Charge them a hair less than a rental house's posted prices and you'll pretty much own the sync box after one film. Compared to the days of labor in post, that rate is a steal for them. Everyone wins. The only way that might fail is if post took an all inclusive flat rate to go from raw footage on drives to finished product. Then THEY goofed up and will learn a valuable lesson from it.

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To answer your questions:

1. TC crosstalk will be likely in the Zoom. I'd avoid feeding TC to one of the zoom tracks.

2. TC settings should be confirmed with Post before anything. However, that said, for a feature film, I DOUBT you will use DF.

3. On the F5, there's an TC IN/OUT switch. Set it to IN so that the camera receive timecode from the BNC connector. Your TC settings in the camera should be Reset and Free Run. Then you can plug in you TC box through the BNC and the camera should run in sync. For further details look at page 62 of the F5 manual.

4. As many have said above, I would try to find better options for a recorder. If production is unwilling or unable to provide for one, then you must manage their expectations regarding the use of TC. I think feeding scratch track to camera and sync'ing with PluralEyes will probably be a cheaper solution for them in such case.

 

Good luck!

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" no-budget feature, got hired and then they decide to tell me they want TC. Now, I'm using an SQN with a zoom h4n and i've been trying to figure out how to do this as I've never done TC before. "

unreasonable expectations...

the SQN -Zoom combo says a lot...(what Jim Gallup posted!) basically, you are using a great sounding mixer, and are feeding the much lesser quality recorder available to you..
" How bad, if any, will noise from the TC track bleed to the audio track? "

that is very difficult to say,  as there are numerous factors involved.

" Do I set the camera to DF or NDF? "

That is very difficult to say, and is dependent on what the actual workflow is. --do "they" know what they are doing ? I agree: it's utterly pointless to record one track of audio and one of TC on a zoom,

Workflow Test Required!!

" I assume both the camera and the zoom will be "slaves" to the TC generator. "

this is not as difficult, as there is no capability for the Zoom unit to be either a master, or a slave to SMPTE/EBU TC.

" Any other issues I should be aware? "

well,  yeah!

 

" my only worry being the restriction to movement "

no budget = no extras

 

BTW: what Rob Lewis said! ::)

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Christopher - i have Tajimi curly tails and the extension. If you find out what the best level settings are I'd love to hear it.

 

Johnpaul - No offence taken, they get what they pay for, for sure. Hell, for the money they're paying me I'm doing them a favour, i'm basically getting kit hire fee only. I was actually hoping they'd want a pair of radio mics so I could finally buy two g3's (i know they're no lectros but its a start) 

 

John - its the 4S IVe. Is that lead for sending a scratch track to the zoom and record TC on the scratch track?

 

Jose - thanks for the answers. I've told the producer his options (tails to camera, pluraleyes or TC recorder) waiting to hear back from him.

 

Senator - I bought the zoom when i started a couple of years ago and i figure there's no point buying an "in-between" recorder like a Tascam hd-p2, just wait till i can afford an sd/zaxcom. Would you advise otherwise?

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so.. today.. Owner of F5 had updated his firmware..

sent tone out of a Wendt x5 at  line level..

set camera inputs to line, and set "audio level" menu to -20 on both channels

sounded good, no clipping..

 

for free range part of day...

had to set camera to mic in levels for a 416 onboard and a UCR411... Channel with wireless wanted +30, and onboard mic wanted +60

 

I am not convinced these scales are actually db meters...

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I am not convinced these scales are actually db meters...

 

That's probably true. The Senator's comment above to do a Workflow Test is a good one: run three minutes of sound and picture, clap at the head, clap at the tail, then pull the files out and see how well they sync up (and whether they stay in sync) in a laptop editing program like Final Cut. Also, see where the sound levels come up. It would help to lay down a few seconds of tone at some point just so that you can see where the tone comes up on the FCP meters. 

 

It is baffling why camera makers don't have a standardized audio level metering scheme that follows normal pro audio convention, like a normal scale with 0dBfs at the top and a -20dBfs mark somewhere in the middle. And the characteristics of the metering have to follow normal industry convention; I usually like Peak/VU, but it'd be nice to change this for those who don't.

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Maybe you need some real answers..

 

1. How bad, if any, will noise from the TC track bleed to the audio track? And how do I stop it from bleeding? (i read somewhere to keep the volume in the middle but I wasnt convinced)

 

With unbalanced circuits, particuarly ones with 3.5mm jacks and thin cables (and thus moderate resistance ground connections), will have typical crosstalk of the order of -60dB, though the figure can often be much worse. That means that TC signals will need to be very low to prevent audible effects. Remember that crosstalk is audible ~below~ any noise floor. Recommendations often hint at using -30dB below reference as a compromise between the TC being readable and minimising crosstalk.

 

2. Do I set the camera to DF or NDF?

 

You don't mention what camera it is, but for file-based systems you can always change the headers afterwards, so setting of correct TC format is less important than it once was. DF is used for TV transmission, NDF for film use as a general rule. Auropean rates are simple, US rates confuse everyone. It is more important that frame rates for the camera, and TC rates for an audio recorder are the same at recording (and changed together later if needed) simply because it causes less confusion.

 

3. I assume both the camera and the zoom will be "slaves" to the TC generator. I checked the F5 manual and it doesn't have an option for slave/master. Do I set it as master or will it automatically accept the TC from the generator?

 

You do indeed need to understand the basics rather better - no offence meant since you had the wit to at least ask (and a great many users of TC have staggeringly little understanding of the subject). If you "slave" a camera to TC you have to do it in such a way that the picture frames always receive one TC number per frame ~exactly~. There are several ways to acheive this including the use of genlock, but a treatise on that would take too long here. Beware that many professionals are very wobbly about this part of synchronisation. If you slave an audio recorder the same thing applies except that you are labelling a fixed number of audio samples (different for each video format). In every case you need to arrange that sample (and frame) rates are locked (and even phased) with TC numbers.

 

Hope that helps ...

 

Chris Woolf

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@ MarcW

I'm not going to be allowed enough camera and file access to do that test (EPK shoot on something huge with publicist and field producer very present) with this example of this camera, unless I am very lucky.

 

However, I am comfortable with the solution we have for our hardlined feed to camera for sit downs.

I have spoken to our post, and the line level setup  ounds good.  As we are single system (despite all my requests), TC stability is not in play.

 

I was asked if I could use the camera itself as a 4 track ISO recorder over AES/EBU input.. but that firmware has not yet been released for this camera (Sony claimed December of this year as their target date for that feature).

 

I see a zax AES fan out cable in my near future purchases... and an adjustment to the package rental accordingly

 

@Chriswoolf  point #2.. the OP said it was a Sony F5..

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@Chriswoolf  point #2.. the OP said it was a Sony F5..

 

Apologies - I was scanning the first post quickly and missed that.

 

An F5 can accept ext TC and be "slaved". If you feed in continuous TC you need to genlock the camera too. Conventionally a Lockit or Deneke box is used since these provide the sync/TC locking and phasing. Genlocking a camera is not difficult but you need to understand the principles clearly since you can cause a lot of grief if you don't. If you are providing a momentary jam - TC applied to the camera and then removed - then no genlock is required but  periodic rejamming is needed to prevent drift or jumps.

 

Setting the DF/NDF is done within the Timecode sub-menu of the F5.

 

Chris Woolf

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No worries I still don't think the OP should concern himself with TC at all on his budget... just let the camera be the 2 track recorder...

 

I concur.

 

However I got the impression OP wanted to learn about the subject as well. TC and synchronization are fields that cause immense confusion. Discussing the subject and putting what-if and how-can questions is a good way to do that. That way, when you finally get to genlock three cameras, record sound across a pair of linked file recorders, and generally supervise sync and TC, it proves to be less of a scary scenario than it would be otherwise.

 

Chris Woolf

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