psd_multitaper output conversion to dB (Welch)

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1

Dear experts,

I would like your expert opinion to convert values from psd_multitaper to dB (from plot_psd).
Currently, I use simple conversion to dB via 10 log10 multiplication. I believe there is also a correction needed for sampling rate (2048 Hz) and from m^2 to cm^2. Still the values don’t make sense to me. The plot_psd (from Welch) results in +30 dB for low frequencies,
but the psd_multitaper returns negative values for all frequency bands.

Is it possible to convert multitaper values in the range of the “Welch-values”. Perhaps anyone has dealt with this trick before, or can enlighten me. (The previous questions on the forum don’t solve this matter fully either).

Many thanks in advance!

Jan-Bernard

MNE version: 0.24.0
Ubuntu 18.04

2

Dear reader,

I solved the question myself: For future reference It was apparently more easy than thought…
The following conversion was needed for EEG:

psds =
psds_scaled = psds * 1e6**2 #V to muV^2
psds_scaled_dB = (10 * np.log10(psds_scaled))

See also : Confusion surrounding Epochs.plot_psd() units · Issue #9868 · mne-tools/mne-python · GitHub