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Audio Loudness Meter Extended 5.1

Audio Loudness and True Peak Meter VST, AU, AAX plugin
and standalone application, BS1770, EBU R128, ATSC and ARIB compliant

ALM5.1 Audio Loudness Meter Plugin

ALMx 5.1 is more powerful and flexible than ever, with these new options. Try it.

Vectorscope for Stereo and 5.1(with selectable pairs)

The main purpose of the vectorscope is to display a stereo image of the audio signal. The channels can be changed from the dropbox, you can switch between L/R, L/Ls and R/Rs. The history of the Vectorscope will fade out slowly, providing you with the information needed to determine if the stereo separation is according to your needs.

Correlation Meters

The correlation meters indicate the degree of similarity between the channels: L/R, L/C, R/C, Ls/Rs, L/Ls and R/Rs.

If the audio of the channels is similar, the drawn values will be in the +1 zone and if it’s considerably different, the values will be in the 0 zone. When the two channels are out of phase, the meter draws in the -1 zone. ALMx 5.1 uses a color code: green tones for the +1 zone, yellow tones for the 0 zone and red tones for the -1 zone.


An important feature of the ALMX 5.1 is the log option, which allows you to view the loudness graph at all times.

  • Markers for “Start” and “End”, allowing you to see the statistics for a specific portion of the graph
  • Duration for Program Loudness and Loudness Range
  • Max. Momentary Loudness value with time position, calculated from the values selected between the markers
  • Max. Short Term Loudness value with time position, calculated from the values selected between the markers
  • Start and stop time for the material
  • On the graph, you can view either the short term value or the momentary value and the timestamp
  • Files saved in .xml and .csv format
  • The logs are updated in real time
  • Option for high/low resolution
  • Variable short term limit
  • Zoom in/out option for the graph

ALM5.1 Audio Loudness Meter Plugin True Peak

Sound Field Display

The Sound Field can use one of the two types of loudness, to create a real time view of the surround image of the signal:
  • Momentary Loudness
  • Short Term Loudness
The axes are the same as for the Loudness Meter Indicator or for True Peak Meter, depending on your choice. For True Peak Loudness, the representation of LFE channel will be included. The Max. Short Term Loudness threshold will also be used, the bar becomes red if the value is above the limit.



The ALMx 5.1 Downmixing algorithm is in concordance with ITU specifications. This way you can be sure that your program material is compatible with sound systems which are provided with a lower number of channels. Downmixing is used only for metering, the audio material isn’t actually changed.

Loudness Descriptors

  • Integrated Loudness (Program Loudness) – describes the long-term integrated loudness of an audio material from ‘start’ to ‘stop’;
  • Momentary Loudness – calculated with a time window of 400 ms;
  • Short Term Loudness – calculated with a time window of 3 s;
  • Loudness Range – loudness dynamic range from ‘start’ to ‘stop’ that helps you decide if dynamic compression is necessary;
  • Max True Peak Level – indicates the maximum value of the signal waveform in the continuous time domain (this value is calculated using inter-sample peaks that can be missed in quantization).


  • Standalone Loudness and True Peak Metering for Windows and OSX
  • Channel Formats: mono, stereo and 5.1
  • Full compliance with loudness standards : BS-1770 (rev.3), EBU R128, ATSC A/85 and ARIB; presets and color coding are also available
  • Complete loudness measurements using universal descriptors: Integrated Loudness/Program Loudness, Momentary Loudness, Short Term Loudness, Loudness Range
  • Real-time metering for Momentary Loudness, Short Term Loudness and Loudness Range
  • Accurate measurements for all the usual sample rates: 44.1 kHz, 48 kHz and multiples
  • Real-time Vectorscope for True Peak and Momentary Loudness
  • Sound Field Display
  • Correlation meters for L/R, L/C, R/C, Ls/Rs, L/Ls and R/Rs channels
  • Downmixing from 5.1 to stereo
  • True Peak Level Metering with peak hold;
  • Max True Peak Level (calculated using inter-sample peaks that can be missed in quantization);
  • Measurement logging in .csv and .XML files
  • Variable thresholds for True Peak and Short Term Loudness
  • Variable colors for loudness descriptors, according to the comfort zone
  • Lock option and kiosk mode option

ALM5.1 Audio Loudness Meter Plugin True Peak ALM5.1 Audio Loudness Meter Plugin True Peak

ALM5.1 Audio Loudness Meter Plugin True Peak

Presets and color coding

For a better monitoring of the Integrated Loudness, ALM 5.1 uses a color code. This way, you will know how your program loudness fares compared to the accepted tolerance of each standard. The accepted tolerance zone is the range of loudness that is comfortable to the listener. Note that the Integrated Loudness may not be constant through the program. It can vary within a specific zone according to the content requirements.
The color of Integrated Loudness parameter is:
green- if the Integrated Loudness matches the standard’s specifications;
                                   yellow- if it’s around the standard’s specification, but still you must turn the volume up/down;
red- if the material is annoyingly loud/soft.                                                    

If you choose to use the presets, the default threshold for the Short Term Loudness will be the one specified by each standard.
You can select another value according to your own needs.
The color of Short Therm Loudness descriptor is in accordance with the threshold from the Settings window.
If the measured value is above the threshold, the SL is green and if it is beyond the threshold, the SL is red.

ALM5.1 Audio Loudness Meter Plugin True Peak


  • Metering Standards: EBU, ATSC and ARIB specifications ;
  • Loudness Scales : +9 LU and +18 LU;
  • Loudness Units : LUFS,LKFS and LU;
  • True Peak ref. level : -18 dBTP and -20 dBTP
  • Integrated Loudness gating off : the gate isn’t used and the Integrated Loudness and Loudness Range values are calculated for the entire audio material/li>
  • True Peak max. level : from -12 dBTP to 0 dBTP. Sets the maximum value for the signal waveform calculated using inter-sample peaks that can be missed in quantization. Above this value the peak led indicators are red (the level is the same for all the channels)
  • Short Term max. level : from -24 to 0, if the unit is set to LUFS or LKFS and from 0 to 24, if the unit is set to LU. If the threshold is reached, then the value of the short term loudness will become red
  • Peak hold : from 0 s to 10 s. Represents the period of time the Peak holders are on
  • Overload hold : from 0 s to 10 s. Represents the period of time the Peak Led indicators are on

Audio Settings

The flexible and intuitive audio routing interface makes it easy for you to configure the input and outputs according to your needs.
  • Variable Sample Rate
  • Variable Audio buffer size
  • Every possible channel routing combination available
ALM5.1 Audio Loudness Meter Plugin True Peak

Minimum System Requirements

Dual Core CPU with SSE2 support
Dual Core CPU (Intel or AMD) with SSE2 support
Windows 7


You can download a 30-day trial, without feature limitations.