<- tb8:logic_functions|Logic Functions ^ tb8:start|Toolbox8 Software ^ tb8:logic_delays|Logic Delays ->


====== Level Detection ======

With the logic system of the mixing device you can monitor level and correlation of up to 24 audio signals at the same time. To configure these level detects, in the project tree, select ''<Device>/Logic/Level Detects''.

Level detectors are configured accordingly to control logic functions that are activated if the level of the monitored audio signal exceeds a set threshold. These logic functions are available in the ''Logic Sources'' window under ''Level Detect/LV <serial number>: <Name>'' or ''Correlation Detect/LC <serial number>: <Name>''. For each entry in the ''Level Detects'' list, in the ''Logic Sources'' window one entry each is inserted in ''Level Detect'' and ''Correlation Detect'' section.

You can output the state of the logic functions for example via a GPO or have it shown with an LED of an user defined key on the console or on a TFT View. 

[{{ :tb8:ppm_new.png |//Level Detects Page, Configuring a new Peak Programme Metering//}}]

To insert a new level/loudness/correlation detector to the ''Level Detects'' list, click ''Add''. To remove a selected entry from the list, click ''Remove''. Both functions are also available by right-click in the list.

To adjust the potentiometers in the ''Level Detection'' and ''Metering'' Section, click on the desired potentiometer. Hold the mouse button and move the cursor to the left or the right to change the value. Alternatively, click on the desired potentiometer and change the value using the following keys: 

^cursor keys^level potentiometer^correlation potentiometer^hold time potentiometer^attack potentiometer^release potentiometer^ 
^right arrow key or up arrow key|steps of +1 dB|steps of +0.1|steps of +0.1 s|steps of +0.1 ms|steps of +0.01 s|
^left arrow key or down arrow key|steps of -1 dB|steps of -0.1|steps of -0.1 s|steps of -0.1 ms|steps of -0.01 s|
^Pos 1|-40 dBint|-1.0|0.1 ms|0 ms|0.1 s|
^End|+10 dBint|+1.0|100 ms|250 ms|2.5 s|
^Page up|steps of 5% (+2 dB)|steps of 5% (+0.1)|steps of 5% (+4.9 s)|steps of 5% (+12 ms)|steps of 5% (+12 ms)|
^Page down|steps of 5% ( -2 dB)|steps of 5% (-0.1)|steps of 5% (-4.9 s)|steps of 5% (-12 ms)|steps of 5% (-12 ms)|

The level detects can also be used inverted as logic source in logic functions or GPOs to detect undershootings. By an AND concatenation in a logic function with the logic source Pulse 1 (or 2, 3) also flashing functions when exceeding or falling below a certain level can be configured. 

The correlation detects can be used as logic source to recognise whether both parts of a stereo signal are similar (1) or at least relative (0.1-0.9). In the negative range, the logic source shows faulty stereo signals (-1 to 0) that can not be used for mono. 

===== Peak Programme Metering =====

To configure a PPM level detector, follow these steps:

  - In the ''Level Detects'' list, select the level detect which you want to configure.
  - In the Edit Level Detect area, type an appropriate name in the ''Label'' box. This label may be up to 10 digits long. 
  - Select the measuring mode ''Level Detect''
  - To assign an audio source, click select. The ''Audio Sources'' window opens. 
  - In the ''Audio Sources'' window, select the audio signal that you want to monitor and click ''Assign''. Alternatively you can double-click on the desired audio source or drag it to the ''Source'' box. 
  - If ''Stereo'' is selected, additionally, the following channel is also used for monitoring. In most cases, this is the right channel of a stereo signal. 

Settings in the ''Level Detection'' section:

  - At the ''Level'' potentiometer define the desired threshold value. You can select a value between -40 dBint and +10 dBint in steps of 1 dB.
  - Independent from the set threshold value at the ''Level'' potentiometer, you can set a value between -1.0 and 1.0 for the correlation monitoring at the ''Correlation'' potentiometer. If this value is exceeded, the logic function ''Correlation Detect/LC <serial number>: <Name>'' is activated. 
  - At the ''Hold Time'' potentiometer you can define how long the logic functions ''Level Detect/LV <serial number>: <Name>'' and ''Correlation Detect/LC <serial number>: <Name>'' remain active after the threshold is exceeded. You can set the hold time between 0.1 ms and 100 ms.

<WRAP center info 80%>
**Note**\\  The logic function ''Correlation Detect'' is intended for metering. The correlation detection only works for signal levels greater than -30 dBint. That is why DHD does not recommend to use this function as a logic source.
</WRAP>

Settings in the ''Metering'' section:

  - With the ''Attack'' potentiometer you can define how quickly the PPM display in the TFT displays react. You can set this attack time between 0 ms and 250 ms.
  - With the ''Release'' potentiometer you can set the release time of the PPM display in the TFT displays. You can set this time between 0.1 s and 2.5 s.

<WRAP center tip 80%>
**Tip**\\  To emulate an analog level meter with an integration time of 10 ms concerning to IEC 268-10 (PPM, Type I) and DIN 45406 respectively, please use the following values:\\ • Attack = 2 ms\\ • Release = 0.7 s\\ Please use the following values to emulate a digital level meter:\\ • Attack = 0 ms (or 1 ms, if integration time is required)\\ • Release = 0.7 s
</WRAP>

For creating a 5.1 surround peak meter see [[tb8:element_configuration#ppm_51_channels|PPM 5.1 Channels]]

===== True Peak Metering =====

Since TB8 v8.1.8 and Firmware v8.1.9, True Peak metering with 8-times Oversampling is available. This Feature can be used the same way as a usual PPM meter (Level Detect). For the True Peak metering usage, the PPM meter TFT Element has a new scale type: ''Digital True Peak +3..-60dB''.

<WRAP center round info 80%>
**Note**\\  True Peak Metering uses a lot of DSP resources. Use True Peak metering only if this metering type is really required.
</WRAP>

To configure a True Peak level detector, follow these steps:

  - In the ''Level Detects'' list, select the level detect which you want to configure.
  - In the ''Edit Level Detect'' area, type an appropriate name in the ''Label'' box. This label may be up to 10 digits long. 
  - Select the measuring mode ''True Peak Meter''
  - To assign an audio source, click ''Select''. The ''Audio Sources'' window opens. 
  - In the ''Audio Sources'' window, select the audio signal that you want to monitor and click ''Assign''. Alternatively you can double-click on the desired audio source or drag it to the ''Source'' box. 
  - If ''Stereo'' is selected, additionally, the following channel is also used for monitoring. In most cases, this is the right channel of a stereo signal. 

The Settings in the ''Level Detect'' and ''Metering'' Sections are the same as described in [[#Peak_Programme_Metering|PPM Metering]] above.

===== R128 Loudness Metering =====

The loudness metering is available for all 52/XC/XD/XS Cores.

<WRAP center round important 80%>
**Important**\\ 
  * The Hardware needs the license 52-8581 Enhanced DSP Processing (necessary for all 52/XD2, 52/XD, 52/XC2, 52/XC, 52XS2, and 52/XS Cores).
  * 52/XS2 and 52/XS core hardware additionally requires the license 52-1950 XS Core extended feature upgrade to be able to configure the function and the TFT views.
</WRAP>

The loudness metering in DHD consoles follows the EBU R128 standard.

To configure the R128 loudness meter in the TB8 software, select <Device>/Logic/Level Detects. Add a new level detect and in the Edit Level
Detect area select EBU R128 Loudness Meter. Assign for example the PGM Bus as Source for the R128
Loudness Meter.

[{{ :tb8:loudness.png?nolink |//R128 loudness meter configuration//}}]

2. In the project area, select <Device>/TFT Views. Select an existing TFT Master view or add a new one. On the Design tab, drag a ''Loudness Meter'' element from the Available Elements list to the View Presentation area.

  * Loudness Meter element contains only the bar (incl. peak display and short value arrow)
      * short value graphically shown as a small triangle on the left side
      * true peak display on top of the meter bar (oversampled x4, -1dBFS)
  * if required, Momentary, Short, Integrated, Loudnes Range values (M, S, I, LRA) can be added as extra Label Elements - size, label and colour can be customized
  * start, stop and reset are available as key function, gating (triggered by external sources) can be realised via virtual keys.

Since TB8 v8.1.8 and Firmware 8.1.9, the Loudness Meter Element can now be configured further:

  * The Main Bar function can now be configured as ''Momentary'' (standard value) or ''Short''
  * The Triangle function can now be configured as ''Short'' (standard value), ''Momentary'' or ''Off''

3. On the Edit tab, select the Data Source for the Loudness Metering elements.

{{tag>[EnhancedDSP]}}