Hybrid files are the masked track and the ultrasonic track layered on top of one another. This process is additive and causes the overall volume to increase by approximately 1-3 dB where the two forms of audio are present at the same time.
This is not adjusted for.
Ultrasonic only audio is impossible for most people to hear consciously, and therefore it is easy to overvolume or undervolume the program without realizing it and wither deprive yourself of effective programming, or expose yourself to very high volumes that could be detrimental to your hearing if you are using headphones. This is why we say not to use ultrasonics with headphones.
But the standard calibration process uses the masked tracks to set the maximum volume for the ultrasonic track.
Therefore, to set a safe volume for the hybrid track, you would simply play it at a volume at which the audible portion is comfortable to listen to. This automatically calibrates the ultrasonic audio to within 1-3 dB of the maximum you would have otherwise achieved during standard calibration.
If this volume is uncomfortable for you as a result of the ultrasonic portion of the audio, simply lower the volume a click at a time until it is not.
The resulting volume should be safe for use with headphones.
If you notice that you get tinnitus or your existing tinnitus is made worse by using the hybrid track at this volume, it is a good idea to switch to masked for a while until the tinnitus fades and if you decide to use the ultrasonic or hybrid track again, lower the volume further.
Posted in: Using Subliminals