Specifications

EAW Smaart 6 Operation Manual Analysis Modes and Display Types

Press the Start button in the real-time window to begin all real-time measurement

operations. When the RTA display is active, time-domain audio data from the A/D

converter of your sound hardware is continuously transformed into the frequency domain

using a Fast Fourier Transform (FFT). The FFT data can be plotted on the RTA display

in real time, either in raw narrowband form or processed into octave or fractional-octave

bands. The magnitude for each frequency band (or data point) on each of the two input

channels is updated several times per second, depending on the speed of your computer,

FFT size, and sampling rate.

The (y-axis) magnitude range of the RTA plot can be changed using the RTA dB Range

Max and Min fields in the Spectrum tab of the Options dialog. The magnitude range

can be further restricted by dragging a rectangular region within the plot. There also hot

keys for plot ranging (see Keyboard Shortcuts on page 103). Click on the numbers for

either axis to return the scale to normal (determined by RTA dB Range values).

Using the default Full Scale display calibration, the maximum magnitude value of 0 dB

is equal to the maximum A/D amplitude value obtainable at the current sampling resolution

(i.e., 16/24 bits per sample). That means that a sine wave input signal with amplitude

exactly equal to the maximum input voltage of your sound hardware’s A/D converter

should yield 0 dB at the sine wave’s frequency on the RTA plot. Full Scale calibration

is adequate for applications concerned only with the relative differences between

frequencies. Smaart 6 also includes a calibration function that allows moving the decibel

range of the raw incoming data up or down to correlate to Sound Pressure Level (SPL)

or another external reference.

The RTA’s frequency scale may be displayed in octave, 1/3-, 1/6-, 1/12-, or 1/24-octave

resolution. Set the frequency scale for the Spectrum displays from the Scale control

under the Spectrum button.

The frequency range of the Spectrum and Magnitude plots may be set using hot keys

(page 103) or by recalling one of the four Frequency Zooms (set in Options

>Zoom)

assigned to the 1-4 keyboard keys. The x- and y-axis ranges of most Smaart charts can

be set by clicking and dragging to draw a rectangle around the desired plot area, then

releasing the mouse button. Click the frequency numbers to return the scale to normal.