Creation of an "equal" linear comparison filter for A / B comparison
If you want to better assess the effectiveness of a filter created in Acourate with an A / B comparison, i.e. with / without filter, an empty filter can be created for this. This allows the music to pass unhindered like electricity through a wire. Since a correction filter results in a level reduction, an equal level reduction is added when the filter is created. (This step can be omitted when using the Acourate Convolver, since a separate level reduction can be specified for each filter bank.)
After calculating the correction filter with Macro4, the approximate level reduction is displayed in dB in the message window. If you have forgotten the value - when you open the Macro4 window again, the value is displayed again as 'Previous Gain Ratio'.
For a better understanding of how an empty filter works, it can be created alongside a correction filter that has been created. To do this, load the existing correction filter in curve 1, activate curve no.2 and then call the test signal generator under Generate> Test signal:
Setting sample 32768 (the middle sample of the filter) to 1 generates a central Dirac pulse. This results in a delay similar to that of the filters that were created with Macro 4. It is also possible here that , for example, sample 0 must be set to 1. Then the filter has no delay.
The result looks like this: A Dirac pulse is generated with a perfectly linear frequency response with a gain of 0 dB.
Now the filter has to have its level reduced, it should be an equally loud comparison filter: Use TD-Functions> Gain and enter the previous gain ratio from Macro4.
The comparison filter now shows the result. The generated filter is valid for all sampling rates and channels, so it can e.g. can be saved as Cor1L44,… Cor1R192.