Differences

This shows you the differences between two versions of the page.

--- audio:rephase [2020/11/29 13:35] – [Maximum Response Peak Output] oscar
+++ audio:rephase [Unknown date] (current) – removed - external edit (Unknown date) 127.0.0.1
@@ Line 1: / Line 1: @@
-====== 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 ====
-Make sure that the target curve is completely below 0 dB.
-After clicking on the generate button the maximum gain value is shown. See the "max response: -0.4 dB" in the example below. This value we be above 0dB if there is an EQ settings with positive gain in one of the banks. If this value is greater than 0 dB, you will risk distortion.A good setting is between -0.5 dB and -1.0 dB.
-{{ :audio:rephase-max-response.jpg?200 |}}
-This can be corrected by adjusting the potentiometer located under the first Rephase tab.
-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.
-{{ :audio:rephase-output-setting.jpg?100 |}}