bouldersoundguy
Well-known member
I see a lot of wave file mixes mastered to 0 dBFS peak. That has the potential for producing peaks above 0 dBFS. In fact, it's virtually guaranteed given modern audio production methods. There are two reasons for this.
First is how digital data is converted to analog. DACs have to process the audio with a low pass filter during conversion to properly reconstruct an analog waveform. As a result, the analog waveform can "overshoot" the peaks represented by the digital samples ("intersample peaking"). This will cause some converters to distort on peaks. The "True Peak" measurement in LUFS meters is designed to predict this level. I find that a digital peak level of -0.3 dBFS gives sufficient room to prevent excess True Peak levels from a wave file in most cases.
But there's a second problem, which is the effect of compressed file formats. I've found that converting to mp3 results in an increase in a file's peak levels. It varies a bit depending on the file, but more than 0.5 dB is typical. In the attached images, you'll see that the True Peak level increased 0.8 dB and the LUFS integrated level decreased by 0.2 dB as a result of converting a file from wave to 128 kbps mp3.
This is why I master files with a full 1.1 dB of True Peak headroom. It's also probably why the meter turns red for anything above -1 dB True Peak (see red marks above the level trace).
First is how digital data is converted to analog. DACs have to process the audio with a low pass filter during conversion to properly reconstruct an analog waveform. As a result, the analog waveform can "overshoot" the peaks represented by the digital samples ("intersample peaking"). This will cause some converters to distort on peaks. The "True Peak" measurement in LUFS meters is designed to predict this level. I find that a digital peak level of -0.3 dBFS gives sufficient room to prevent excess True Peak levels from a wave file in most cases.
But there's a second problem, which is the effect of compressed file formats. I've found that converting to mp3 results in an increase in a file's peak levels. It varies a bit depending on the file, but more than 0.5 dB is typical. In the attached images, you'll see that the True Peak level increased 0.8 dB and the LUFS integrated level decreased by 0.2 dB as a result of converting a file from wave to 128 kbps mp3.
This is why I master files with a full 1.1 dB of True Peak headroom. It's also probably why the meter turns red for anything above -1 dB True Peak (see red marks above the level trace).
