-
Audio: floating meters vs. multitrack meters
I’m new to this site, using FCP Studio, all latest versions on PM G5 2.0. I’ve just completed a 60 min. doc with 14 tracks of audio and have discovered some strange inconsistencies especially concerning levels. Each track is set to stereo mix (0 dB) – 24bit, 48kHz. Monitoring via firewire through stereo speakers.
1) Audio cleaned and normalized to 0 dB in Peak LE are much quieter in FCP (-6 dB in some cases). Why is this?
2) Using the tool bench Audio Mixer, and after compensating for pt. 1 by raising levels, individual track levels appear well above 0 dB, yet remain under 0 dB in the Master level reading. This is the same regardless of whether I’m downmixing or not, or playing the individual clip in the viewer. Regardless, audio does not sound distorted in any way. I thought increased tracks were supposed to result in a louder signal (hence the default downmix of -3 dB) but I’m experiencing the opposite.
MY QUESTION: Should I be monitoring using the meters in the tool bench Audio Mixer and later raising the master; or, monitoring according to the floating meters and raising each individual clip?
3) Lastly, why are so many posters suggesting never going above -3 dB? Wouldn’t one want to get as close to 0 dB as possible without clipping? Especially when the end result is on DVD.
Thanks for any tips or advice in advance!
-
2 Replies
-
[SammyClam] “3) Lastly, why are so many posters suggesting never going above -3 dB? Wouldn’t one want to get as close to 0 dB as possible without clipping? Especially when the end result is on DVD.”
The problem is when you are too close to “0” you will likely MISS some peaks that go above that “absolute” ceiling and cause distortion.
-3dB is still a bit “too close for comfort”.
If you are sure you are not making any amplitude errors, you can go all the way to zero, but that’s your decision.
The difference in LOUDNESS (what the listener actually HEARS) when you mix your PEAKS between 0 dB, -3 dB or even -12 dB can be slight.
-
I assume that we are talking about -3db Full Scale in the digital world and not analog levels.
Levels are a funny thing when going in and out of digital devices. We have a stand alone Pioneer PRV-LX1 DVD deck with SDI input. It absolutely will not handle SDI audio at levels much above -8 without distortion. We try to keep it averaging around -12dbFS.
I just got a DVD from a touring group yesterday with severely clipped audio on the track. Upon contacting the production house, I was informed that it was burned right from the editing computer and that the audio levels never “hit 0dbFS” and there is no way it could be clipped. I told them to actually listen to their own DVD if they didn’t believe me. They called back later and admitted that it was in fact clipped. They couldn’t figure out how that could have happened.
Be careful with those levels.
Tom
Reply to this Discussion! Login or Sign Up