Specifications

EAW Smaart 6 Operation Manual Analysis Modes and Display Types

Note that because the time dimension of the data window function used by the time win-

dowing routine is actually double the size of the specified window time, the maximum

window is equal to half the time constant of the FFT size/SR selected in the Frequency

Response tab of the Options dialog.

NOTE: When FPPO is selected from the FFT menu, the Time Window controls are

disabled because it is incompatible with this feature.

See Frequency Response on page 95 for a complete list of time window parameters.

One trade-off with time-windowing is that the time constant of the windowed transfer

function is reduced. The window function therefore acts as a high pass filter, thus re-

moving some amount of low-frequency information from the windowed trace.

3.2.6 Averaging and Smoothing

In Smaart, nearly all averaging is based on RMS averaging, aggregated either linearly,

with all frames in the average contributing equally to the averaged result, or exponentially,

giving more weight to the most recent data and less to older data. Linear averaging is

also sometimes referred to as arithmetic. Smaart offers linear averaging options from 1

(no averaging) to 128 frames. There is also a linear infinite averaging option that keeps

a running average while the analyzer runs (or until you flush the averaging buffer). The

Fast and Slow averaging options available for Spectrum and SPL measurements are

exponential averages.

NOTE: As a general rule, select an averaging parameter that allows reasonable mea-

surements without taking too long to collect. Changing the number of averages

clears the buffers so it takes a few seconds for the display to stabilize.

Averaging Data Type

The Average Type for Frequency Response measurements is selected from the Frequency

Response tab of the Options dialog. Smaart 6 offers two Average Types for Frequency

Response measurements that stabilize the display and make it easier to interpret: RMS

(Root Mean Square) and Vector. Vector and RMS refer to the type of data that goes into

the averaging routine.

RMS is more forgiving of wind or movement that can cause slight variations in arrival

times between successive FFT frames. RMS also permits more late arriving reverberant

energy into the Frequency Response measurement so it tends to correlate well to the

subjective human perception of overall system tonality. RMS averaging is done after

the complex vector has been converted to magnitude and phase data.