The DEMO version of Dirac 4.1 is contained in a self-extracting executable. This version does not allow you to save files, and only calculates parameters for the 2 kHz octave band. Do not install the DEMO version on a system where a licensed version of Dirac is installed.

Click here to get the DEMO of Dirac 4.1

The Dirac 4.1 update can only be installed over a licensed copy of Dirac 4.0.

Click here to get the Dirac 4.1 update (3MB)

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New in version 4.1:

• Added the Sound Insulation Index (SI) parameter described in the ENV 1793-5 standard.

• Added the option to save WAVE (.wav) files without Dirac specific information. This makes it possible to use WAVE files created by Dirac with software that does not support RIFF INFO chunks, such as MatLab. 

• The Save Project Data function now saves parameter values for both channels where possible.

• The L_eq, L_Aeq and L_Ceq are now only available when the external impulse measurement method is used, or when the measurement stimulus has a white spectrum (e.g. MLS and lin-sweep, without source filter). For nonwhite stimuli, the L_eq is not valid due to the particular implementation in Dirac.

• The BR(L) is now only available when a system calibration has been applied to the measurement. The system calibration compensates for the influence of the measurement chain on this system parameter. 

• Asynchronous measurements now result in higher INR values.

• The criterion for displaying (and colouring) speech intelligibility values has been changed. These values will be displayed in grey when, in one of the relevant frequency bands, the INR is lower than 15 dB or the MTF cannot be calculated.

• The default name for saved tables and graphs now includes the project name.

• Fixed a software problem, making the free field system calibration available again.

• Fixed software failures that could occur while canceling auralisation calculations and while mixing noise.

• Sound devices are no longer erroneously marked asynchronous during the sound device calibration procedure.

• Decimal points and comma's are no longer mixed in saved tables.

New in version 4.0:

• Much improved asynchronous (open loop) measurement results. Asynchronous measurements can now have almost the same quality as synchronous (closed loop) measurements. Asynchronous measurements can be averaged to increase the INR. Measurements where a CD or MP3 player can be used to playback an MLS or sweep stimulus are important for instance when measuring the speech intelligibility of PA systems in train stations, stadiums, airport halls etc.

• Option for manual entry of SNR values for STI calculations. Using asynchronous measurements with pre-averaging, you can now measure the noise-free speech intelligibility. Later you can easily investigate the impact of noise by manually entering different SNR values.

• Auralisation function. The auralisation function will automatically resample the IR to match the sound material. You can correct the results for the frequency response of the sound source that was used to capture the IR to remove the colouring caused by the source.

• New parameters: C₃₀, C_x, D_x, IACC_x, RT, T_x, Hallmass (H), Bass Ratio (BR(RT) and BR(L)), L_Aeq, L_Ceq, Magnitude Pink (3dB/octave compensated magnitude view). You can specify your own integration intervals for Clarity (C_x), Definition (D_x) and Inter-Aural Cross Correlation (IACC_x). You can also define a custom decay range for the reverberation time (T_x). All custom defined parameters are available in table and graph formats and can be saved, copied, printed etc.

• User defined parameter tables. In addition to the pre-defined tables for reverberation, energy ratios, spaciousness etc., you can now define your own tables to contain exactly the parameters you need for the job at hand.

• Project save and load functions. When working with a large number of measurements, this can be a big time-saver. The group setup in the statistics window, and the files contained in these groups can now be saved in a project file. The project file can later be opened again for quick access to all files in the measurement session.

• Calculate and export multiple parameters in a single operation. You can now specify any number of parameters that should be calculated for a particular project. The results for all these parameters for all impulse responses in the project are exported to a file that can be opened in a spreadsheet program.

• Undo function for waveform Edit operations. The number of operations that can be undone is only limited by the size of you disk drive, so for all practical purposes the Undo is unlimited.

• Overlays in time and frequency domain views. You can now compare measurements graphically to the level of individual reflections. The impulse responses can be aligned perfectly based on a cross-correlation, and you can quickly switch the foreground and background curves.

• Optional linear scale in ETC view. By popular request the linear scale for the Energy-Time Curve, or reflectogram, is back.

• Optional grid in time and frequency domain views. You can now also change the graph colours.

• Faster sound device calibration procedure supporting a wider range of devices. Dirac no longer requires that the sound device (driver) supports the mixer API. Only the wave API is required. This enables the use of many sound devices that use their own proprietary mixer software.

• Support for 24- and 32-bit sound devices and .wav files. The maximum sample rate was increased to 192 kHz for high quality 1:10 or 1:20 scale model measurements.

• Option to change the sample size and sample rate of a measurement using a high quality resampler.

• Optional bandlimited sweeps to protect the sound source.

• AutoMeasure can now also be based on a time interval instead of a trigger signal. This is useful for monitoring applications where a measurement must be taken regularly regardless of the presence of any sound.

• There are of course many more smaller improvements in Dirac 4.0, such as the forward integration view and the amplitude zoom in the impulse response view.