I'm using an external meter to measure the digital audio level coming out of my Finalizer. Although the 0 dBfs LED's on my Finalizer's output meter light up, my external meter reads a level lower than 0 dBfs. Why is this?
The digital outputs of the Finalizer can be prevented from ever hitting 0 dBFS in several ways:
Peaks can be clipped in the Normalizer, the limiter or the output stage, the Digital Ceiling can be lowered, or the Output Fader can be turned down by a small amount.
The softclipper in the LIMITER section can also prevent the audio level reaching 0 dBfs, as you can push the audio into the softclipper to get increased loudness of up to 3 dB, without reaching 0 dBfs. Only with the softclipper set to 0% hard, the softclipper will not affect the audio level.
The most tricky one is the Digital Ceiling, because it can be turned down just a fraction of a dB - and therefore never show overload on a full scale sample counter.
By default the Finalizer 96K's bypass function is set to NORMAL in the MIDI/UTILITY MENU. In this case the DITHER, LOWCUT FILTER and LOOK AHEAD delay remain unchanged, even when bypassing the unit. To achieve TRUE bypass in the digital domain, when using the BYPASS function you can set this PARAMETER to THRU. This will pass all 24bits unaltered.
Lesson number one is that counting samples is a very easily fooled way of determining level. Clipping 0.01 dB before full scale produces just as much distortion as hitting full scale hard, but is hidden from downstream detection.
For more info regarding 0 dBFS+ levels in digital mastering, please refer to this paper 0 dBfs+ in digital mastering.
More accurate metering can be achieved by using intersample peak detection like on our System 6000 or the Brickwall Limiter plug-in for PowerCore and Pro Tools. The Finalizer meter follows normal mastering standards, which are easily fooled.