Quote:
Originally Posted by
bossobass 
For example, the RS meter is known to not be accurate for measuring peak dBSPL of a snapshot of a scene, or a single frequency sine wave tone, but it will be very accurate when comparing the reading of one subwoofer vs another in the same room and under the same conditions.
Bosso
If you use the correct RS SPL meter and the correct meter settings, the measured peak SPL levels of a RS SPL meter are right in the ball park of the theoretical calculations!
Quote:
Originally Posted by
bossobass
When fairly accurately configured, SpecLab will show the relative intensity of each frequency in the spread of frequencies in any given encoded effect. Because digital formats have a brick wall ceiling at 0dBFS (decibels below full scale), above which there is clipping and the resultant terribly distorted sound, any single frequency is always encoded at minus 'x' dB below 0dBFS, so that the sum of all of the frequencies in the effect do not exceed 0dBFS.
So, looking at the scene of the giant dragon hitting the ground in HTTYD, the highlighted ULF frequencies are shown to be encoded at approximately -5 to -10dBFS. Ultimately, when played through a properly calibrated system that's flat to 3 Hz, the total dBSPL of any given effect snapshot will be a maximum of around 121dB, but actually closer to 118dB in most cases.
Bosso
Your numbers are way off. When you measure more than one channel (AKA BM in use) with any software then you can easily get close to +10 to +15 dB FS (AKA theoretical FS) total output levels due to signal addition.
The nominal peak output level for any single frequency bin in Spectrum Lab will be in the -20 dB FS area for each channel with typical audio content. The ballpark level of the entire composite signal can be estimated with the amplitude bar graph that most people either do not use or do not calibrate. In any case, the Spectrum Lab FS calibration is only accurate for evaluating one single channel at a time. If your source material is DD, then the DD Dialnorm value that was used also has to be compensated for.
