I have QA400 audio analyzer. I can export spectrum data to .csv and read it into Excel. However, the frequency scale of the data is linear. Meaning the values are every 2.9Hz and not a logarithmic scale. And the values are in dB. Is this data suitable for an AVERAGE(signal)/STDEV(noise) type of calculation?

  • $\begingroup$ Before that, you should convert from dB to natural scale by $$\text{signal} = 10^{(\text{signal_dB}/10)}$$ $\endgroup$
    – msm
    May 10, 2017 at 21:02
  • $\begingroup$ Yeah, I got that far but the scale is still an issue. For example, from 100Hz to 200Hz there are around 34 data points. But from 10KHz to 20Khz there are 3420. That's going to screw up the AVERAGE and STDEV calculations no? I need to interpolate a log scale somehow. $\endgroup$
    – squarewav
    May 10, 2017 at 21:11
  • $\begingroup$ Not really. If they are in linear scale, then it should be fine. $\endgroup$
    – msm
    May 10, 2017 at 21:33


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