small inaccuracy of riaa compensation

[morillon]

here I was using sweeps taking tens of minutes in virtins... (the more classic "white" approach that I point out with mt takes much much less time and the riaa "without doubt").... if necessary in virtins I will just use the "playback" file (python is extremely powerful and precise but I do not have the "python" skills to remove the added hs filter) ...


https://forums.melaudia.net/showthread. ... pid=202661

https://www.avnirvana.com/threads/using ... tage.5623/

[VirtinsTech]

Sorry, I am having a bit of trouble understanding your English. As shown previously, the RIAA curve can be obtained with a high resolution (>=32768 points) within 1 second if a "periodic white noise" is used as the test signal.

In fact, in Multi-Instrument, you could use Recording RIAA in the Signal Generator to generate an RIAA pre-emphasized "periodic white noise", and then apply Reproducing RIAA in the Spectrum Analyzer to deemphasize it. Ideally, the result should be a flat horizontal line, as shown below. Again, this can be achieved within 1 second.

SignalGeneratorRecordingRIAA-SpectrumAnalyzerReproducingRIAA.png (117.64 KiB) Viewed 110 times

[morillon]

observe my level of precision of level
(observations rather around 0.05 0.1db etc.)

[morillon]

My point and my observation is just that it seems that there is an little approximation in your 2 riaa files..4k/10k

[VirtinsTech]

Thanks, I'm starting to understand what you meant. Yes, there are some minor discrepancies in the RIAA curve data across different software applications. If you generate an RIAA pre-emphasized "white" test signal from one application and then de-emphasize it with another, the resulting spectrum may display some minor artefacts due to these RIAA discrepancies. This issue can be avoided by using the same software for both pre-emphasis and de-emphasis, see figure below.

SignalGeneratorRecordingRIAA-SpectrumAnalyzerReproducingRIAA1.png (113.25 KiB) Viewed 107 times

Please find attached the updated and more precise RIAA FCF and FRF files to be used in Multi-Instrument.

RIAACurveData.zip

(9.08 KiB) Downloaded 8 times

[morillon]

i try it and seem ok now...! top....

(here just to validate observe the behavior of a means of acquisition of fr above" 1-2k to 20k,or more", to observe the behavior and help to adjust somes parameters (capacitance etc) of mm cartridge etc, seems quite sufficient and rigorous for my use )

[morillon]

new riaa.PNG (45.54 KiB) Viewed 90 times

example

[VirtinsTech]

Thank you for helping to refine the RIAA curve used by Multi-Instrument. The updated RIAA FCF and FRF files will be included in the next software release.

[morillon]

your software deserves a "riaa correction" hdg

[morillon]

perhaps in your various tests you have come across the fact that it is probably comfortable that "the correction remains in place" whatever the manipulations differents types of mesureaments ... as long as we do not decide to explicitly remove it .... (?)