The time constant is smaller (0.125 seconds) and can therefore reflect insensitive fluctuations the previous weighting. I have a very small time constant. It is used to judge how influences in the human ear, the intensity of sounds of short duration. Peak allows quantifying levels of extremely short duration (50 microseconds) sound pressure peaks. Enabling the determination of risk of hearing damage to impulses.
Specialized functions: this aspect governed by the design of each model of sound level meter. These functions give possibilities for the most comprehensive study of the soundscape that is parsed. They can be values RMS, peak, filter to correct the effects of screen and sound incidence front or random, calibration history storage, overload, criterion level threshold level, filters for analysis infrasounds and auxiliary outputs ultrasonic detectors: must have current and direct current (DC) output AC (AC). The AC output is essential for potential measurements with tape for digital audio (DAT, acronym in English) the DAT is connected to the AC outlet obtaining a record of the signal that allows you to analyze it later. An acceptable output impedance can be 100 ohm. Not all sound level meters offer auxiliary AC output. Storage capacity: depending on the goals that are set. It is important if DAT recorders are not available.
Since can keep logs for later analysis with appropriate software. For example, the Mediator 2238 of Bruel & Kjar has a memory of 2 Mbytes that can store up to 500 files, with the date, start time, configuration and calibration data. It has the advantage that it allows to retrieve data and display them on the screen, print them or transfer them to computer for a top Studio. The drawback is that analysis softwares are sold as optional items. The cost of the investment is fired! Optional software modules: closely linked to the previous feature. Lets you perform more complex analysis of the signals: analysis statistical and spectral, periodic reports in the case of the analysis of frequencies, on its own initiative, will require sets of filters, 1/1 and 1/3 octave (which in many cases are supplied as optional).