Work out mixing gain staging instantly with clear inputs, formula shown and shareable results.
The trim is simply target minus current level in decibels, and uncorrelated tracks sum at 10 log of the track count, so 24 tracks add about 14 dB on the bus. Ignoring summing gain is why mixes clip the master bus even when every channel looks safe, and staging to -18 dBFS leaves room for that build-up.
Track trim
trim dB = target peak - current peak
Summing gain
gain dB = 10 x log10(number of tracks) for uncorrelated material
trim dB = target peak - current peak. The trim is simply target minus current level in decibels, and uncorrelated tracks sum at 10 log of the track count, so 24 tracks add about 14 dB on the bus.
Ignoring summing gain is why mixes clip the master bus even when every channel looks safe, and staging to -18 dBFS leaves room for that build-up.
Enter current track peak level, target track peak level, number of tracks summing. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.