Frontend setup

The menu item Frontend setup opens a new window, where all relevant settings for the in- and output channels to be used can be made.

File

By Frontend setup / File configurations once set for the in- and output channels can be saved and reloaded.

Default

Under Default convenient basic configurations can be selected for specific hardware setups. Default settings available are Robo3, RME Multiface II, Robo2 + Multiface II, Digital and DBS1.

Input view / Output view

Here the elements present in the signal chain of an individual measuring setup can be switched on and off. Only settings of the selected blocks are being displayed. In the input section there is Frontend inputs, Probes and Preamps available; the output section comprises Frontend outputs, Internal power amplifiers, External power amplifiers and Loads & output calibration.

Probes

Probes contains settings for transducers converting a mechanical quantity (e.g. sound pressure or acceleration) into electric signals.

Sensor

By default the input channels are numbered consecutively. These numbers can be replaced by representative labels, for example "measurement microphone left".

Serial identifier

Input field for serial numbers of sensors. Up to now this information is not being utilised. One possible application for example is the logging of serial numbers in Excel protocols of quality control processes (QC/Process control).

Microphone compensation

Here the compensation file for a microphone used (or any other transducer) can be included. The file must be present in WinMF format and be deposited inside the Exciter directory. Every measurement is being multiplied by this file, hence it needs to contain the inverse frequency response of the microphone. The compensation file can be selected by right-clicking the filename-field and opening the context menu.

Sensortype

Here the type of sensor used is to be selected. For mere electrical measurements, e.g. of equalisers or controllers, voltage is to be chosen, pressure for microphone measurements, velocity for velocity sensors, acceleration for accelerometers, and so on. The results of the measurements are then displayed using the corresponding units.

Sensor characteristic

When using microphone probes, this drop-down menu allows to keep as additional information, whether it is a free-field or a diffuse-field microphone. For the case of accelerometers and velocity sensors the vectorial orientation can be noted down. Up to now this information is not being utilised. Possible applications are for example 3D animations of measured velocity distributions.

Sensitivity

For a correct acquisition of measured data the accurate declaration of the Sensitivity of the transducer is crucial. When using a microphone, the corresponding sensitivity needs to be entered here, for example 15mV/Pa (to be typed in as 0.015 V/Pa). With a calibrator available the sensor can also be calibrated by the menu AD/DA / Mic. calibrate in the time domain window. After a successful calibration the colour of the respective channel switches from red to green; the sensitivity determined has then been adopted automatically.

External preamp

External preamp gain

If an external preamplifier is used for measuring, the respective gain must be entered here.

External preamp max. output

The maximum output voltage of the external preamplifier can be specified here.

Frontend inputs

The input channels are activated by the check boxes next to their labels. With each measurement all the channels checked here are being recorded, no matter if there is a signal present at the respective input or not.

Frontend sensitivity

When using a Robo2 or Robo3, here the input sensitivity of channels 1 and 2 can be changed synchronously. The maximum input voltage is adjustable in steps of 20dB from -40dBu up to +40dBu (Robo2) and from -34dBu up to +46dBu (Robo3). When the input level is too low, a lower voltage range is to be selected; when overdriving the input, the voltage range is to be raised. Levels way out of range, for example from power amplifiers, can damage the Robo! Therefore, in case of unknown signal levels, a low sensitivity should be started with (e.g. +46dBu). With a Robo the maximum input voltage values of channels 3-18 are given by the hardware and are not switchable by the user; for Multiface II without Robo this applies to all channels.

Frontend phantom power

In case phantom power is remote-controllable, here it can be switched on and off.

Frontend outputs

Here the outputs of the frontend are activated by checking the boxes. The output signal is sent to all activated output channels with the same level (in dBFS).

Frontend sensitivity

When using a Robo2 or Robo3, here the maximum output level of channels 1 and 2 can be changed synchronously, between 0dBu and +20dBu with a Robo2, between +6dBu and +26dBu with a Robo3. For all other channels, and with a Multiface II without Robo, the maximum output levels are given by the hardware and are not switchable.

Internal power amplifiers

Robo2 and Robo3 frontends include internal power amplifiers on output channels 1 and 2. The correct values are already set and not changeable.

Internal amp gain

The amplification factor of the power amplifier integrated in the Robo is read here. It is fixed to 20dB in Robo2 and 0dB in Robo3.

Internal amp max. out

The maximum output level at the output stage of the Robo is read here. The maximum level at the banana plugs of Robo2 or the Speakon connector of Robo3 is +26dBu.

External power amplifiers

External amp gain

If an external power amplifier is used for measuring, the amplification factor in dB must be entered here.

External amp max. out

To avoid overdriving an external power amplifier, the maximum output voltage in dBu is to be specified here.

Loads and output calibration

Load impedance

For correct determination of electrical power the nominal impedance of the loudspeaker is to be entered here.

Output calibration

Here for each output channel of the frontend a calibration factor can be entered. When playing back files by ADDA/Play these calibration factors are used to calibrate the playback chain (external power amplifier + loudspeaker or headphone). This allows for example recordings stored in PA to be reproduced with the right sound pressure. No other menus use this calibration factor.