Behringer DSP8024 user manual RTA mode

ULTRA-CURVE PRO DSP8024

At first, the level will be determined before processing. This information is sent to and displayed by the level meter. Apart from this the input signal will be delayed if a delay time is set. Once again, a level will be determined, this time from the delayed signal. This will be used to control the noise gate. At the same time, the overall level (master volume) will be set. This is done prior to processing, so that the processing filters in the signal path will not be overloaded. Next are the graphic and parametric filters. 34 filters will be operated in sequence, starting with the lowest frequency (20 Hz). The last three in the sequence are the parametric filters. They have a special characteristic in that they receive control signals from the feedback destroyer.

After processing by the filters the signal will be controlled for feedback. When the feedback destroyer is switched on, a control signal for one of the parametric filters will be generated. In addition to this the filtered signal will be sent to the digital limiter. When switched on, it ensures that the signal level will be limited to the level set. Finally, we find the level control of the noise gate. Here the input level is continuously compared with the threshold setting. As soon as the level drops below the threshold, the ULTRA-CURVE PRO output will be muted. Following this final processing function, the output level will be measured and sent to the level meter. The processed signal for the left channel will then be sent on to DSP 2. It carries out the same processing as above, but solely for the right channel.

5.3 RTA mode

The integrated RTA in the BEHRINGER ULTRA-CURVE PRO allows audio spectral analysis with a 1/3 octave resolution to an accuracy of 0.5 dB. The associated display may be customized in a number of different ways to suit your preferred way of working. Press the RTA key to access the RTA mode.

The digital signal processing in the ULTRA-CURVE PRO takes place in the two DSPs, each of which has a specific function. In equalizer mode, each channel has a DSP assigned to it. In analyzer mode, the signal processing is divided between the two DSPs, the first dealing with the RTA functions, the second looking after signal generation and equalizing. The procedures which we will describe here are carried out extremely quickly, in some cases simultaneously. The sequence as described does not always reflect the real processing sequence, instead it follows a more logical train of thought.

DSP 1:

First we must choose a signal source for measurement. When mono is selected as signal source, both input channels will be summed. Next the signal level will be adjusted. This adjustment may be fully automatic (gain mode = auto). The signal will be analyzed and the measured levels prepared for the display.

DSP 2:

First of all, the signal to be measured will be generated (a sine wave with variable frequency, or white or pink noise). The signal will be then adjusted to the required level. Finally, the measurement signal will be filtered, just as in equalizer mode. The filter processing corresponds to the equalizer setting of the channel currently active. The measurement signal generated and filtered will be sent simultaneously to both outputs. When the auto-Q function is switched on, the filter parameters for the selected channel(s) and the output selection are automatically set.

Fig. 5.3: Block diagram of the ULTRA-CURVE PRO software in RTA mode

28 5. ULTRA-CURVE PRO STRUCTURE