REW Beta Release Import Frequency Response issues

[pinox67]

Testing my signal processing programs, sometimes I produce a csv file containing the Frequency Response of a filter and then I import it REW with "Import frequency response" item.
Below there is a simple low pass Butterworth filter at 1KHz, 2nd order (formatting with tab separator is lost in the cut&past).
Despite the fact that the filter is at 0dB at low frequency, the SLP & Phase graph show it at 3dB level with dBFS or dBr vertical scale.
Moreover, if I request the generation of Min Phase, strange things happen: both magnitude and phase curves are replaced (instead to add new curves).

Are above behaviour normal?

______________________________

1.00 -0.00 -0.08
1.26 +0.00 -0.10
1.59 -0.00 -0.13
2.00 -0.00 -0.16
2.52 -0.00 -0.20
3.17 -0.00 -0.26
4.00 -0.00 -0.32
5.04 -0.00 -0.41
6.35 -0.00 -0.51
8.00 -0.00 -0.65
10.08 -0.00 -0.82
12.70 -0.00 -1.03
16.00 -0.00 -1.30
20.16 -0.00 -1.63
25.40 -0.00 -2.06
32.00 -0.00 -2.59
40.32 -0.00 -3.27
50.80 -0.00 -4.12
64.00 -0.00 -5.19
80.63 -0.00 -6.55
101.59 -0.00 -8.26
128.00 -0.00 -10.43
161.27 -0.00 -13.18
203.19 -0.01 -16.68
256.00 -0.02 -21.18
322.54 -0.05 -26.98
406.37 -0.12 -34.54
512.00 -0.29 -44.46
645.08 -0.69 -57.38
812.75 -1.57 -73.55
1024.00 -3.22 -91.92
1290.16 -5.76 -110.01
1625.50 -9.02 -125.54
2048.00 -12.69 -137.80
2580.32 -16.56 -147.18
3251.00 -20.52 -154.34
4096.00 -24.51 -159.84
5160.64 -28.52 -164.11
6501.99 -32.53 -167.44
8192.00 -36.54 -170.06
10321.27 -40.56 -172.13
13003.99 -44.57 -173.76
16384.00 -48.59 -175.05
20642.55 -52.61 -176.08
26007.98 -56.64 -176.89
32768.00 -60.67 -177.53
41285.09 -64.72 -178.05
52015.96 -68.79 -178.45
65536.00 -72.88 -178.78
82570.19 -77.03 -179.04

 

[John Mulcahy]

It loads correctly for me (with the current 5.40 beta build):

If you use "Generate minimum phase" for a measurement without an impulse response REW will generate one for it. Better may be to use the "Minimum phase version" measurement action from the All SPL graph, that will produce a new measurement. You will need to apply suitable tails and warping, e.g. these settings:

produce this response:

 

[pinox67]

Thank John.
Well, if you use for vertical scale dBFS or dBr, the level is set instead at 3dB:

If I generate the min phase, from SLP & Phase view, with setting like yours:

Add LF tail: Start: 20 Hz, Slope: 0.0
Add HF tail: Start: 80KHz, Slope: -12 dB/octave
Apply freq. warping to HF tail: On

I obtain this:

It seems that these curves replaces the original curves (!).

If I do again the min phase generation, a new curve min phase is generated.

I use REW 5.30.8 on MacBook Pro Intel, macOS Sonoma 14.3.

 

[John Mulcahy]

if you use for vertical scale dBFS or dBr, the level is set instead at 3dB

Your text file has SPL and phase values, it is not meaningful to use dBFS or dBr in that case as there is no reference for them without an impulse response.

If I generate the min phase

Please see my reply above:

If you use "Generate minimum phase" for a measurement without an impulse response REW will generate one for it. Better may be to use the "Minimum phase version" measurement action from the All SPL graph, that will produce a new measurement.

 

[John Mulcahy]

I've made changes for the next build so that using "Generate minimum phase" on a measurement imported from a text file which included phase will generate an IR for the measurement using the original phase data as well as generating the minimum phase IR, making it behave more like a measurement that already had an impulse response.