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Table of Contents
Rephase FIR Tuning
For each individual stereo channel do the following steps:
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).
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.
Configure parameters and generate filter
Configure following rePhase parameters, set:
- Taps : 65536
- FFT length : 131072
- Centering : middle, use closest perfect impulse
- Windowing : Hann
- Optimization : extensive to -100dB
- Rate : 96000
- Format : 32/64 bits float lines (.txt)
- Filename :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
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.
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.
