Type of emphasis

This combo box contains the filter(s) used for pre- and de-emphasis. The MLS signal is initially white, which means that it contains an equal amount of all frequencies. For most acoustics measurements it gives a better result to use a signal that gives more power to the lower frequencies. Selecting LowBoost200HzShelvingFirstOrder it will boost the frequencies below 200 Hz with 20 dB using a first order filter. For more information read How to add pre-filtering (emphasis) to the excitation signal (MLS)? in the FAQ.