Additional Decibel Clarifications
As of 1.4, every character's Decibel Gain has been buffed by ~1.285x. On-field characters gain 100% of the attack's Decibels, whereas off-field characters gain 50% of that attack's Decibels.
Compared to the current Decibel Gain:
On-field Decibel Gain: ~128.5%
Off-field Decibel Gain: ~64.25%
Additional Decibel Gain effects such as "Attribute Anomaly", "Interrupt", "Chain Attack" etc also follow this split. The Decibel Gain from these effects has not been buffed.
source: leifa