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mixer’s audio meter and Final Cut’s audio meter are showing different readings
Hello,
The audio meter on my mixer and the audio meter in Final Cut Pro are showing 2 different readings. When a clip is reading in the red (over 0 dB) on my mixer, Final Cut Pro reads the signal at about -12 dB. Does anyone know what could be causing the disparity between these 2 readings.
Thanks. I appreciate any insight and info you are able to share
Jason
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3 Replies
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The meters in FCP are representing digital levels with 0DbFS being the highest reading possible. You mixer is most likely showing analog levels with 0Db being considerably less level than 0Db on the digital scale. -20Db on the digital scale (depending on your reference) is about the same as 0Db on your analog mixer. 0Db on your FCP meters would be about +20Db on your analog mixer, considerably higher than it should be in the analog world.
So basically, athough the units on both scales are the same (Db) the reference points for digital scales and analog scales are very different. The levels you mentioned in your post actually sound about right.
Tom -
0db in FCP meter would only be +20 in analog if you were crazy enough to make your tone -20 (that’s pretty daring) and then peak your levels near zero! Big recipe for disaster.
A better plan is to keep tone at about -14, then peak around -4. Giving you a maximum of +10 for peaks in analog, which good equipment should be able to handle.
The basic bottom line is over 0 is clipped. Not just distored. Clipped. Gone. Nasty sounding! So no matter what you set your tone at in FCPs digital realm, the lower you set it, the more headroom your analog equipment has to handle (if you use all your digital headroom).
Confusing (at first) I know. But it’s been this way for 10 years or so.
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Brett,
The reason that -20dbFS equates to 0VU is ancient, but it is true that 0dbFS is +20VU. You can measure the analog out of my digi beta if you doubt this. Broadcast levels require that tone be at -20dbFS and that peaks not exceed -10dbFS. This forum is littered with constant mistakes about what levels to use but these are the SMPTE broadcast rules. PAL is similar except -18dbFS is ref tone with peaks to -10bdFS.
You can do your own thing in house but please don’t advise that using -20dbFS is crazy as it is mandatory if you wish to deliver to broadcasters world wide.
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