Originally Posted by
RMC
RE An SPL Meter will tell you how loud the loudest sound is not the overall level of the passband in question.
Its more nuanced than that, having two SLMs and one RTA. SLM is certainly not an RTA giving instantly level per frequencies, though you could do it on a number of spot frequencies with SLM, just longer.
In peak mode you get the loudest, user choice, however set in average mode the SLM provides the average sound level readings, which reduces the influence of some peak in response. What i would call the "sustained level". Therefore you get a good idea of the overall level of the passband in question...