Which Cables Do I Need?

[Peter Moretti]

Originally Posted by Steve House

Was that sending TC or WordClock from the recorder to the PC?

I've been trying to find more info on Avid and other NLEs ability to do something with linear code recorded on an audio track. Avid does have a Read Audio Timecode tool that will read LTC recorded on an audio track and generate an auxilliary timeline from it. Wondering now if any other NLEs have similar tool? Haven't found anything that would work like that in Vegas or Premiere Pro, is Avid the only one? Anyone heard of any add-ins for other NLE's?

This apparently works for Final Cut: http://www.videotoolshed.com/?page=products&pID=26

I wasn't able to find anything for Vegas or Premiere. But since Vegas is so scripting friendly, I IMAGINE it's a possibility.

[Peter Moretti]

Originally Posted by Bob Kerner

... After speaking with them on the phone, it seems like having them make a breakaway that has the correct connectors for my camera is the way to go, as opposed to buying a standard one and adding adapters to get down to mini plug size. I'd rather spare myself the aggravation of adapters cables hanging all over the place. Though you might want the adapters and a standard cable if you plan to change cameras in the near future...

Bob, just be sure that the cables going to the HV-20 fits not only its mic input but also delivers a mic level signal, otherwise you'll have to attach an attenuator. I believe most line level to mic level attenuators connect to XLR to mini, not mini to mini. So if you'll be adding an attenuator, then you may actually WANT the cable for the camera to be XLR.

[Peter Moretti]

Is there a certain length that should be avoided because its too long a distance for the signal to cleanly travel, or is this really a moot point (practically speaking) with XLR cables?

[Seth Bloombaum]

Originally Posted by Peter Moretti

Is there a certain length that should be avoided because its too long a distance for the signal to cleanly travel, or is this really a moot point (practically speaking) with XLR cables?

Well, not quite moot for many of us who are doing work in larger rooms. I recently had to go through the math for a 420' run of line level...

There is a formula:
-3 dB Frequency = 1 / (cable length x capacitance per unit length x output Z x 2 x Pi)
for determining the high-frequency cutoff point of a particular cable. Longer cables tend to affect the signal as a low-pass filter (cut off high freqs.) Output Z refers to the output impedance of the source. This effect is known as "line loading", and is all about the total capacitance of the cable. The manufacturer supplies a spec, for example "60pf/foot", pf referring to picofarads of capacitance.

Suffice to say that (using pro low-impedance devices) any pro cable ought to get you at least 100' at mic level and 150' at line level, and usually more.

Radio frequency interference (RFI) is quite another matter, and may occur with any cable length. Here the remedies are: monitor always, balanced cables and circuits, test the cables, shorter cables, longer cables, different cables, move the cables, don't run audio cables parallel to power cables or other metal, etc. which sounds intimidating but in practice only occasionally occurs with pro equipment.

I'd certainly agree with those who've posted above that 25' is a very practical length for audio-for-video in field work.

[Bob Kerner]

Originally Posted by Peter Moretti

Bob, just be sure that the cables going to the HV-20 fits not only its mic input but also delivers a mic level signal, otherwise you'll have to attach an attenuator. I believe most line level to mic level attenuators connect to XLR to mini, not mini to mini. So if you'll be adding an attenuator, then you may actually WANT the cable for the camera to be XLR.

I went to the shop today. It's easier to use a standard breakaway and adapter than to make a cable specific for the HV20. Would also be unreasonably expensive according to the sales guy.

[Peter Moretti]

FWIW, this is the cable configuration I believe I'll need to get the 744T's timecode into one of the HV-20's audio tracks:

LEMO to XLR cable. XLR to XLR attenuator. Mini stereo to two XLR Y-adapter.

[Steve House]

Originally Posted by Peter Moretti

FWIW, this is the cable configuration I believe I'll need to get the 744T's timecode into one of the HV-20's audio tracks:

LEMO to XLR cable. XLR to XLR attenuator. Mini stereo to two XLR Y-adapter.

Looks good to me. Are you going to put a scratch mono audio track on the other channel? Don't forget to slate your takes - I still have my doubts about this workflow doing much for you in terms of streamlining the sync process and it would be good to have slates and a scratch track as a backup. And be sure to experiment with some practice shoots before going out to do it 'for-real' to make sure everything works - really looking forward to reading a report back to us detailing your workflow and experiences in post-production - what you did, what worked and what didn't - when you get the chance.

[Peter Moretti]

Originally Posted by Bob Kerner

I went to the shop today. It's easier to use a standard breakaway and adapter than to make a cable specific for the HV20. Would also be unreasonably expensive according to the sales guy.

Bob,

Possibly MY BAD.

I believe the HV-20 may be able to accept line level in. It has both an attenuator and a way to manually adjust down the input level.

I'm looking into it more. (I'm just so busy trying to put everything together, that I over looked this feature.)

That said I've seen a lot of posts saying the HV-20's attenuation options are not enough. But I've also read others that say they are enough. So I guess we'll find out soon either way.


P.S. Poking around has turned up that the attenuator probably cuts the signal by 24dB.