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--- audio:rephase [2020/11/29 13:25] – oscar
+++ audio:rephase [Unknown date] (current) – removed - external edit (Unknown date) 127.0.0.1
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-====== Rephase ======
-Rephase will be used to do the following:
-  - tweak the EQ filter settings generated by REW and;
-  - create the FIR filters for the BruteFIR software convolution engine that runs on Volumio
-For each individual stereo channel do the following steps:
-==== Load Measurement ====
-From the file menu choose "Import Measurement..." to import the REW measurement.
-{{ :audio:rephase-1.jpg?400 |test}}
-==== Adjust the visual ranges ====
-Sometimes the measurement graph from REW is not directly visible, because it falls outside the default visual range of Rephase window. Choose Ranges and adjust Frequency (20Hz - 20kHz) and Amplitude (-20 dB to 100 dB).
-{{ :audio:rephase-2.jpg?400 |}}
-==== Import the REW filter settings ====
-The EQ filter settings generated by REW can be loaded into Rephase by: Under the "Paragraphic Gain EQ" tab choose "import REW filter settings ... " in the "tools" list.
-After loading, Rephase displays the effects on the EQ settings on the frequenty displayed curve. The parametric EQ filters can be changed and optimized manually.
-{{ :audio:rephase-3.jpg?400 |}}
-==== Configure parameters and generate filter ====
-Configure following rePhase parameters: set taps to 65536, rate to 96000, filename to the name of of the filter and choose directory in which rephase will create filter.
-For simple EQ amplitude corrections use "**Minimum Phase**".
-Hit generate to generate and save FIR filter
-Save your work under File/Save settings
-{{ :audio:rephase-4.jpg?400 |}}
-==== Maximum Response Peak Output ====
-Position the target curve at 100% below 0 dB by adjusting the potentiometer located under the first Rephase tab.
-It is after having clicked on the generate button that you have the maximum gain values obtained. max response: -4.33 dB on the example above.
-If this value is greater than 0 dB, you are not good at all, you are going to have distortion.
-This value must be <0dB, there is a 0dB truncation for all values that exceed 0dB, I'm not explaining the distortion that goes with it.
-A good setting is between -0.5 dB and -1.0 dB, with the same value on channels D and G.
-The example above shows the right channel. The maximum response is at -0.62 dB on the G channel, it is the G channel which has chosen the attenuation to be used.
-{{ :audio:rephase-max-response.jpg?400 |}}
-Why is it absolutely necessary to mitigate?
-Imagine a power surge at both 100, 1000 and 10000 Hz, exactly at the same time when recording.
-With the absence of phasing, the three power peaks arrive shifted in time: We can easily have 300 ° of phase rotation between 100 and 10,000 Hz.
-With phasing, power peaks are added.
-The digital part will be more in demand, hence the absolute need to attenuate.
-The dynamics will be greater since the strong signal will be stronger, the weak signal will be weaker.
-This point is important, the pavilions are not the obligatory passage to increase the dynamics of your installation.
-The example is certainly open to criticism, but it still gives a good indication of the reasons which justify a digital attenuation.
-{{ :audio:rephase-output-setting.jpg?400 |}}