Figure 702 shows that when a random level alignment is used to route a signal through the audio system (which is any configuration other than matched noise floors or 0dBFS), the system’s dynamic range is the smallest because the dynamic range of individual terminals always overlaps with others. Matching noise floors minimises overlapping - resulting in a higher dynamic range, but it has the risk that the dynamic range of the last two devices in the signal path - the power amplifier and the speaker - are not always optimally used, causing higher costs. The 0dBFS method has the highest dynamic range because the noise floors are kept at the lowest level at each terminal - resulting in the lowest accumulated noise floor. Also, the 0dBFS method offers the lowest risk of clipping because all terminal clipping levels are aligned to the same level. Only the first terminal, which is normally the microphone’s acoustic input, can clip as a result of excessive input SPL - all other terminals can never clip (at unity gain). The conclusion is that the 0dBFS method is the optimal strategy to make the most use of a system’s dynamic range with the lowest risk of clipping and the lowest cost.
Assuming that the digital part of a networked audio system is always referenced to 0dBFS, there are five main parameters to align the system’s acoustical and analogue terminals: the selection of the microphones, power amplifiers and speakers, the setting of the analogue gain of the head amp, and the voltage gain of the power amplifier.