Recording line level audio

[Mike Burke]

I've just received our camera back from Red with the audio upgrade.
Using release Build 17, upgraded audio board, with new cables.
Audio menu settings are as follows: Line level, 0db.

What I am finding regarding line level audio levels is totally confusing.
With a mixer supplying zero level tone, at line level,
the LED display shows levels well into the orange quadrant of the display.
This is to the right of the solid line.
Having lowered the output of the mixer to the solid line of the
camera LED display, my mixer now displays an output of -10db.
Clearly something is out of cal.

Exactly what levels are these hash marks on the LED display representing?
There is no information in the manual.
What is the proper procedure for establishing a -20db input level
when using a 0db reference tone from a mixer.
Any one from Red?

This camera begins a commercial job Friday, utilizing dual audio recordings.
Thanks much.

[Stuart English]

Process is just this-

Feed the camera - 20dB FS with Line Input gain set to 0dB. The -20dB FS point should line up to the right hand hash mark.

Make a recording and verify in FCP or other software application that you are at -20 dB.

[Mike Burke]

Process is just this-

Feed the camera - 20dB FS with Line Input gain set to 0dB. The -20dB FS point should line up to the right hand hash mark.

Make a recording and verify in FCP or other software application that you are at -20 dB.

Stuart, thanks for the response.

My quandry is this: In order to achieve -20db FS at the camera,
I must set my mixer output to somewhere around -10 VU, with tone as a reference.
Something must be wrong that I'm overlooking.

[Joel Kaye]

Is this any different on build 18?

[Stuart English]

My quandry is this: In order to achieve -20db FS at the camera,
I must set my mixer output to somewhere around -10 VU, with tone as a reference. Something must be wrong that I'm overlooking.

Two questions -

How are you measuring that?

Are you using the mini-XLR to XLR cable or the cable with mini-XLR to mini-XLR plus mini-XLR to XLR adaptor?

As to the Build 18 question: its the same as 17.

[Mike Burke]

Is this any different on build 18?

I can't say as I haven't tested Beta 18 yet. I probably won't get
the opportunity to test 18 by the time this job starts.
What I can say is this has changed as a result of the board upgrade, or
the change to Build 17. I had been on Build 16 up until that point.

I'm really curious as to what others with the new board have experienced.

[Mike Burke]

Two questions -

How are you measuring that? Are you using the mini-XLR to XLR cable or the cable with mini-XLR to mini-XLR plus mini-XLR to XLR adaptor?

1. I'm referring to the VU display on the mixer. Actually, I used a second mixer
to confirm that the mixer wasn't the problem.

2. I've used both: mini-XLR to XLR cable as well as the cable with mini-XLR to mini-XLR plus mini-XLR to XLR adaptor.

[Stuart English]

O.K. The VU on the mixer will tell you the output level of the mixer itself, so lets assume that is fine at 0dB / - 20 dBFS. The reason I ask about the type of XLR input cable you are using is that the mini-XLR to XLR version has a -10dB pad in it to help the older style audio board accept higher input voltage levels than it otherwise could. In the new audio board, those pads are designed into the audio pre-amp so those cables shouldn't be used, else you will over attenuate.

If you were using -20dBFS out of your mixer, and mini-XLR to mini-XLR cable with mini-XLR to XLR adaptor, I'd expect the level being recorded to be fine.

[Mike Burke]

O.K. The VU on the mixer will tell you the output level of the mixer itself, so lets assume that is fine at 0dB / - 20 dBFS. The reason I ask about the type of XLR input cable you are using is that the mini-XLR to XLR version has a -10dB pad in it to help the older style audio board accept higher input voltage levels than it otherwise could. In the new audio board, those pads are designed into the audio pre-amp so those cables shouldn't be used, else you will over attenuate.

If you were using -20dBFS out of your mixer, and mini-XLR to mini-XLR cable with mini-XLR to XLR adaptor, I'd expect the level being recorded to be fine.

I should have specified better.
The mini XLR to XLR cables are custom made at our studio.
They have no pads whatsoever. The input level at the camera is identical
to that of the mini-XLR to mini-XLR cable with mini-XLR to XLR adaptor provided by Red.

It's odd. At this point, I wish I still had one of the padded cables to compare with.
My level seems to be about 10db too hot.

[Stuart English]

re "10 dB too hot .. "

You mean the level you need to send it / the level that gets recorded / or the level the camera sends back?