Behringer DSP8024 user manual AUTO-Qfunction, SINE f, Level

ULTRA-CURVE PRO DSP8024

= sine wave, OFF = signal generator off or INPUT = input signal.

White noise is composed of multitudes of sine waves packed close together, of equal amplitude, whose phases are random compared to each other (statistically different from each other). Their “density” or, spectral intensity is constant at any given frequency. With pink noise, the spectral intensity is inversely proportional to the frequency. In other words, the intensity of White Noise is constant for an absolute bandwidth e. g. 50 to 100 Hz, or 5,000 to 5,050 Hz whereas for pink noise, the intensity is constant over a relative bandwidth e. g. an octave (50 to 100Hz, 5,000 to 10,000 Hz). The difference between white and pink noise can be highlighted by the following example. By taking a situation where the intensity of both pink and white noise found between 20 and 40 Hz is arranged to be the same for both types of noise, it follows that, in the case of pink noise, the same intensity will be found between 10,000 and 20,000 Hz, both bandwidths being one octave. However, as the number of discrete frequencies between 10,000 and 20,000 Hz is five hundred times greater than between 20 and 40 Hz, it follows that the intensity of White Noise present between these two frequencies is correspondingly greater.

SINE f

You use this field to set the frequency of the sine wave. It is adjustable in 1/60 octave steps from 20 Hz to 20 kHz.

LEVEL

The output level can be adjusted in 1 dB steps from 0 dB to -48 dB (with reference to the digital maximum). The internal digital signal generator is routed into the outputs when you switch into RTA mode. As a rule, pink noise is used for system measurement.

+Use the RTA-lock function to prevent accidental signal interruption when using the ULTRA-CURVE PRO for live purposes.

+Before the noise signal reaches the output of the ULTRA-CURVE PRO, it passes the EQ. That’s why the current EQ settings have an effect on the noise signal. As a result, it may be necessary to reduce the level parameter value to i. e. -12 dB, to prevent clipping.

2.3 AUTO-Q function

With the AUTO-Q function it is possible to automatically adjust the equalizer of the UTRA-CURVE PRO. The ULTRA-CURVE PRO measures the total system response including the influence of both the speakers and the room and translates it to the right setting to achieve the desired response.

You can use one of the 100 stored equalizer settings as a target curve for the AUTO-Q function. The curve setting will then correspond to the fader positions of the program selected. (The target curves for each channel may differ from each other). If no program number has been given, “FLAT” will be displayed, meaning that an attempt will be made to achieve a linear response.

It is also possible to use one of the stored EQ curves as a corrective curve for the analyzer measurement, to compensate for any frequency response variations caused by the reference microphone. In the field the chosen program position, and the chosen side (L/R) are displayed. NONE = no corrective curve.

First connect the ULTRA-CURVE PRO as a normal equalizer in the system that will be measured. Connect a reference microphone to the microphone input on the rear panel of the ULTRA-CURVE PRO. Make sure that the RTA setup is correct. The basic settings will be:

Basic settings in the RTA SETUP

SOURCE	MICRO
GAIN MODE	AUTO
MIC CORR	NONE
AUTO-Q CURVE	FLAT
RTA OUTPUT	PINK

Tab. 2.2: AUTO-Q settings

Pressing softkey A in the RTA menu will give access to the RTA toolbox. Pressing the softkey A will open the AUTO-Q menu. In this menu it is possible to choose the left, right or both channels to be measured and

automatically adjusted. left channel, right channel, both channels, first left, then right.

The ULTRA-CURVE PRO automatic measurement procedure has several functions which are designed to prevent unusable settings from being made. For example, it will question whether a band has to be boosted by

2. OPERATION 17